Coccolithophores have unique ability of dual carbon fixation(photosynthesis and biocalcification)and can accumulate bioactive compounds effectively,thereby showing huge potential for CO_(2) bioremediation and simultan...Coccolithophores have unique ability of dual carbon fixation(photosynthesis and biocalcification)and can accumulate bioactive compounds effectively,thereby showing huge potential for CO_(2) bioremediation and simultaneous production of valueadded substances.However,biotechnological exploration of these microalgae is still very limited.In order to develop efficient cultivation strategies of these organisms,we tested the abilities of Chrysotila roscoffensis,a coccolithophore,to grow under mixotrophic and heterotrophic cultivation conditions.It was confirmed that only glycerol stimulated the cell growth of this microalga in the presence of light.To study the physiological significance of mixotrophy,we conducted cell culture experiments both autotrophically and mixotrophically,the only difference of which was optimal amount of glycerol was added under mixotrophic conditions.The results showed that the addition of glycerol substantially enhanced the lipids and monounsaturated fatty acids accumulation of C.roscoffensis,but imposed slight influences on the photosynthetic capacity,pigments content,polyunsaturated fatty acids content,and biocalcification.We concluded that mixotrophy might be an appropriate strategy for exploration of this species for production of high value molecules.展开更多
Cyclotella cryptica,a model diatom known for its robust adaptability to variable salinity and temperature conditions,is a promising candidate for large-scale biotechnological applications.Nutrient availability,particu...Cyclotella cryptica,a model diatom known for its robust adaptability to variable salinity and temperature conditions,is a promising candidate for large-scale biotechnological applications.Nutrient availability,particularly nitrogen and phosphorus,plays a crucial role in the metabolic activities of microalgae,influencing its industrial utility.Exploring the relationship between these essential nutrients and both the yield and biochemical composition of this microalga is crucial for optimizing cultivation strategies.However,research focusing on the effects of nitrogen and phosphorus on C.cryptica remains limited.We investigated the impacts of varying concentrations of nitrate(0.25-3.96 mmol/L)and phosphate(14.4-229.6μmol/L)on C.cryptica culture by analyzing its growth performance,photosynthetic activity,biochemical composition,and biosilica deposition.Results indicate that C.cryptica exhibited enhanced growth,photosynthetic efficiency,and carotenoid production under higher nutrient concentrations.However,the effects of nitrate on macronutrients composition and fatty acids profile differed from those of phosphate.Specifically,increased nitrate levels resulted in higher concentrations of polyunsaturated fatty acids(PUFAs)at the expense of saturated fatty acids(SFAs),while increased phosphate levels were associated with increased PUFAs and reduced monounsaturated fatty acids(MUFAs).Additionally,biosilica deposition was weakened by elevated nitrate but enhanced by increased phosphate levels.This study improved our understanding of nutrient-mediated regulatory mechanisms in diatoms and contributed valuable data to the broader field of algal biotechnology.Moreover,these findings are expected to advance the development of tailored nutrient management strategies,thereby enhancing the industrial potential of C.cryptica.展开更多
The vast osteocytic network is believed to orchestrate bone metabolic activity in response to mechanical stimuli through production of sclerostin, RANKL, and osteoprotegerin(OPG). However, the mechanisms of osteocyte ...The vast osteocytic network is believed to orchestrate bone metabolic activity in response to mechanical stimuli through production of sclerostin, RANKL, and osteoprotegerin(OPG). However, the mechanisms of osteocyte mechanotransduction remain poorly understood. We've previously shown that osteocyte mechanosensitivity is encoded through unique intracellular calcium (Ca^(2+) ) dynamics. Here, by simultaneously monitoring Ca^(2+) and actin dynamics in single cells exposed to fluid shear flow, we detected actin network contractions immediately upon onset of flow-induced Ca^(2+) transients, which were facilitated by smooth muscle myosin and further confirmed in native osteocytes ex vivo. Actomyosin contractions have been linked to the secretion of extracellular vesicles(EVs), and our studies demonstrate that mechanical stimulation upregulates EV production in osteocytes through immunostaining for the secretory vesicle marker Lysosomal-associated membrane protein 1(LAMP1) and quantifying EV release in conditioned medium, both of which are blunted when Ca^(2+) signaling was inhibited by neomycin. Axial tibia compression was used to induce anabolic bone formation responses in mice, revealing upregulated LAMP1 and expected downregulation of sclerostin in vivo. This load-related increase in LAMP1 expression was inhibited in neomycin-injected mice compared to vehicle.Micro-computed tomography revealed significant load-related increases in both trabecular bone volume fraction and cortical thickness after two weeks of loading, which were blunted by neomycin treatment. In summary, we found mechanical stimulation of osteocytes activates Ca^(2+) -dependent contractions and enhances the production and release of EVs containing bone regulatory proteins. Further, blocking Ca^(2+) signaling significantly attenuates adaptation to mechanical loading in vivo, suggesting a critical role for Ca^(2+) -mediated signaling in bone adaptation.展开更多
Osteoporotic hip fracture is associated with significant trabecular bone loss, which is typically characterized as low bone density by dual-energy X-ray absorptiometry （DXA） and altered microstructure by micro-compu...Osteoporotic hip fracture is associated with significant trabecular bone loss, which is typically characterized as low bone density by dual-energy X-ray absorptiometry （DXA） and altered microstructure by micro-computed tomography （pCT）. Emerging morphological analysis techniques, e.g. individual trabecula segmentation （ITS）, can provide additional insights into changes in plate-like and rod-like trabeculae, two major micro- structural types serving different roles in determining bone strength. Using ITS, we evaluated trabecular microstructure of intertrochanteric bone cores obtained from 23 patients undergoing hip replacement surgery for intertrochanteric fracture and 22 cadaveric controls. Micro-finite element （~FE） analyses were performed to further understand how the abnormalities seen by ITS might translate into effects on bone strength. ITS analyses revealed that, near fracture site, plate-like trabeculae were seriously depleted in fracture patients, but trabecular rod volume was maintained. Besides, decreased plate area and rod length were observed in fracture patients. Fracture patients also showed decreased elastic moduli and shear moduli of trabecular bone. These results provided evidence that in intertrochanteric hip fracture, preferential loss of plate-like trabeculae led to more rod-like microstructure and deteriorated mechanical competence adjacent to the fracture site, which increased our understanding of the biomechanical pathogenesis of hip fracture in osteoporosis.展开更多
Type 2 diabetes （T2D） is associated with systemic abnormal bone remodeling and bone loss. Meanwhile, abnormal subchondral bone remodeling induces cartilage degradation, resulting in osteoarthritis （OA）. Accordingl...Type 2 diabetes （T2D） is associated with systemic abnormal bone remodeling and bone loss. Meanwhile, abnormal subchondral bone remodeling induces cartilage degradation, resulting in osteoarthritis （OA）. Accordingly, we investigated alterations in subchondral bone remodeling, microstructure and strength in knees from T2D patients and their association with cartilage degradation. Tibial plateaus were collected from knee OA patients undergoing total knee arthroplasty and divided into non-diabetic （n---70） and diabetes （n = 51） groups. Tibial plateaus were also collected from cadaver donors （n = 20） and used as controls. Subchondral bone microstructure was assessed using micro-computed tomography. Bone strength was evaluated by micro-finite-element analysis. Cartilage degradation was estimated using histology. The expression of tartrate-resistant acidic phosphatase （TRAP）, osterix, and osteocalcin were calculated using immunohistochemistry. Osteoarthritis Research Society International （OARSI） scores of lateral tibial plateau did not differ between non-diabetic and diabetes groups, while higher OARSI scores on medial side were detected in diabetes group. Lower bone volume fraction and trabecular number and higher structure model index were found on both sides in diabetes group. These microstructural alterations translated into lower elastic modulus in diabetes group. Moreover, diabetes group had a larger number of TRAP~ osteoclasts and lower number of Osterix~ osteoprogenitors and Osteocalcin~ osteoblasts. T2D knees are characterized by abnormal subchondral bone remodeling and microstructural and mechanical impairments, which were associated with exacerbated cartilage degradation. In regions with intact cartilage the underlying bone still had abnormal remodeling in diabetes group, suggesting that abnormal bone remodeling may contribute to the early pathogenesis of T2D-associated knee OA.展开更多
Mesenchymal stem/stromal cells(MSCs)are extensively studied as cell-therapy agents for neurological diseases.Recent studies consider exosomes secreted by MSCs as important mediators for MSCs’neuroprotective functions...Mesenchymal stem/stromal cells(MSCs)are extensively studied as cell-therapy agents for neurological diseases.Recent studies consider exosomes secreted by MSCs as important mediators for MSCs’neuroprotective functions.Exosomes transfer functional molecules including proteins,lipids,metabolites,DNAs,and coding and non-coding RNAs from MSCs to their target cells.Emerging evidence shows that exosomal microRNAs(miRNAs)play a key role in the neuroprotective properties of these exosomes by targeting several genes and regulating various biological processes.Multiple exosomal miRNAs have been identified to have neuroprotective effects by promoting neurogenesis,neurite remodeling and survival,and neuroplasticity.Thus,exosomal miRNAs have significant therapeutic potential for neurological disorders such as stroke,traumatic brain injury,and neuroinflammatory or neurodegenerative diseases and disorders.This review discusses the neuroprotective effects of selected miRNAs(miR-21,miR-17-92,miR-133,miR-138,miR-124,miR-30,miR146a,and miR-29b)and explores their mechanisms of action and applications for the treatment of various neurological disease and disorders.It also provides an overview of state-of-the-art bioengineering approaches for isolating exosomes,optimizing their yield and manipulating the miRNA content of their cargo to improve their therapeutic potential.展开更多
Treatment for central nervous system(CNS)disorders is known to be limited by the low regenerative potential of neurons,and thus neurodegenerative insults became known as nearly irreversible ailments.Functional recover...Treatment for central nervous system(CNS)disorders is known to be limited by the low regenerative potential of neurons,and thus neurodegenerative insults became known as nearly irreversible ailments.Functional recovery for acquired CNS disorders,such as spinal cord injury(SCI),traumatic brain injury,ischemic stroke,Alzheimer’s disease,Parkinson’s disease,multiple sclerosis(MS),and for congenital CNS abnormalities,such as spina bifida,is not spontaneous and effective treatments are limited to non-existent.Research in the past decades has proven the regenerative potential of stem cells,especially that of mesenchymal stromal/stem cells(MSCs)from various origins,such as bone marrow,placenta,and adipose tissue.展开更多
The history: Myelomeningocele - also known as spina bifida- is a devastating congenital anomaly of the central nervoussystem that is caused by the malformation of the spinal cordand vertebral column during embryogenes...The history: Myelomeningocele - also known as spina bifida- is a devastating congenital anomaly of the central nervoussystem that is caused by the malformation of the spinal cordand vertebral column during embryogenesis. Depending onthe location of the spina bifida lesion on the spine, patientssuffer from neurological dysfunction ranging from paresisand incontinence to complete paralysis. The current standardof care for spina bifida is in utero surgical repair of the defect,which has been shown to minimize the secondary deficits associatedwith this disorder (Adzick et al., 2011). Despite thesesuccesses, this approach does not reliably improve neurologicfunction of affected children. Several groups, including ourown, have performed studies aimed at augmenting the inutero surgical repair of spina bifida by applying principlesof stem cell and tissue engineering to provide an enhancedprotection of the exposed neural elements (Saadai et al., 2011,2013; Wang et al., 2015; Brown et al., 2016). The ultimategoal of these studies is to improve the neurologic function inpatients while maintaining the benefits of the existing fetalsurgical treatment.展开更多
To explore the possible mechanism of osteogenesis for deciduous teeth stem cells (DTSCs) in vivo/ vitro, stem cells from goat deciduous teeth (SGDs) were firstly isolated, induced and transplanted into immunocompromis...To explore the possible mechanism of osteogenesis for deciduous teeth stem cells (DTSCs) in vivo/ vitro, stem cells from goat deciduous teeth (SGDs) were firstly isolated, induced and transplanted into immunocompromised mice. The SGDs's mineralization pattern and osteogenesis were compared with bone marrow messenchymal stem cells (BMMSCs) from goats. SGDs have similar osteogenic differentiation pattern in vitro and bone-like tissue formation mechanism in vivo to BMMSCs; moreover SGDs have stronger alkaline phosphatase (ALP) gene expression and osteopontin (OPN) gene expression levels than BMMSCs; also SGDs can form more bone-like tissues than BMMSCs when cell-scaffold compounds are transplanted into immunocompromised mice. This pre-clinical study in a large-animal model confirms that DTSCs may be an appropriate source of stem cells in repairing bone defects with tissue engineering.展开更多
MicroRNAs （miRNAs） are a group of regulatory RNAs that regulate gene expression post-transcriptionally by the degradation or translational inhibition of their target messenger RNAs （mRNAs）. Regulation is accomplis...MicroRNAs （miRNAs） are a group of regulatory RNAs that regulate gene expression post-transcriptionally by the degradation or translational inhibition of their target messenger RNAs （mRNAs）. Regulation is accomplished when the 22-25 nucleotide miRNAs bind to complementary sequences in the 3＇-untranslated regions （UTR）. One barrier to miRNA research is to find target genes. Although computational target predictions have shed light on important aspects of microRNA target recognition, questions remain concerning the rates of false positives. In addition, we do not completely understand how microRNAs can recognize and regulate their targets. As such, experimental positive predictions and allow for an unbiased stu ap dy proaches are required, which can reflect in vivo processes, eliminating false of microRNA target recognition. In this review, we summarized experimental approaches that have been described for the identification and validation of mRNA targets associated with specific miRNAs.展开更多
BACKGROUND Endothelial colony-forming cells(ECFCs)have been implicated in the process of vascularization,which includes vasculogenesis and angiogenesis.Vasculogenesis is a de novo formation of blood vessels,and is an ...BACKGROUND Endothelial colony-forming cells(ECFCs)have been implicated in the process of vascularization,which includes vasculogenesis and angiogenesis.Vasculogenesis is a de novo formation of blood vessels,and is an essential physiological process that occurs during embryonic development and tissue regeneration.Angiogenesis is the growth of new capillaries from pre-existing blood vessels,which is observed both prenatally and postnatally.The placenta is an organ composed of a variety of fetal-derived cells,including ECFCs,and therefore has significant potential as a source of fetal ECFCs for tissue engineering.AIM To investigate the possibility of isolating clonal ECFCs from human early gestation chorionic villi(CV-ECFCs)of the placenta,and assess their potential for tissue engineering.METHODS The early gestation chorionic villus tissue was dissociated by enzyme digestion.Cells expressing CD31 were selected using magnetic-activated cell sorting,and plated in endothelial-specific growth medium.After 2-3 wks in culture,colonies displaying cobblestone-like morphology were manually picked using cloning cylinders.We characterized CV-ECFCs by flow cytometry,immunophenotyping,tube formation assay,and Dil-Ac-LDL uptake assay.Viral transduction of CVECFCs was performed using a Luciferase/tdTomato-containing lentiviral vector,and transduction efficiency was tested by fluorescent microscopy and flow cytometry.Compatibility of CV-ECFCs with a delivery vehicle was determined using an FDA approved,small intestinal submucosa extracellular matrix scaffold.RESULTS After four passages in 6-8 wks of culture,we obtained a total number of 1.8×107 CV-ECFCs using 100 mg of early gestational chorionic villus tissue.Immunophenotypic analyses by flow cytometry demonstrated that CV-ECFCs highly expressed the endothelial markers CD31,CD144,CD146,CD105,CD309,only partially expressed CD34,and did not express CD45 and CD90.CV-ECFCs were capable of acetylated low-density lipoprotein uptake and tube formation,similar to cord blood-derived ECFCs(CB-ECFCs).CV-ECFCs can be transduced with a Luciferase/tdTomato-containing lentiviral vector at a transduction efficiency of 85.1%.Seeding CV-ECFCs on a small intestinal submucosa extracellular matrix scaffold confirmed that CV-ECFCs were compatible with the biomaterial scaffold.CONCLUSION In summary,we established a magnetic sorting-assisted clonal isolation approach to derive CV-ECFCs.A substantial number of CV-ECFCs can be obtained within a short time frame,representing a promising novel source of ECFCs for fetal treatments.展开更多
The purpose of this multicenter study was to evaluate the clinical performance of an ultrahigh molecular weight polyethylene (UHMWPE) fiber cable for re-attachment of the osteotomized greater trochanter in hip surgery...The purpose of this multicenter study was to evaluate the clinical performance of an ultrahigh molecular weight polyethylene (UHMWPE) fiber cable for re-attachment of the osteotomized greater trochanter in hip surgery. Included in the study were 85 hips that had undergone surgery with greater trochanter osteotomy, including 50 hip arthroplasty procedures and 35 hip osteotomies. The osteotomized greater trochanter was reattached using one or more UHMWPE fiber cables. The bone union and displacement of the greater trochanter were assessed in radiographs for up to 12 months after surgery. Non-union of the osteotomy site occurred in 4.7% of the cases. In approximately 90% of the cases, displacement was less than 2 mm at up to 12 months after surgery. The UHMWPE fiber cable was a good biomaterial for reattaching the osteotomized greater trochanter and may also be an option for osteosynthesis procedures.展开更多
Bone modeling and remodeling are governed by distinct biochemical processes that may hold unique opportunities for optimizing bone mass[1,2].Remodeling refers to the coupled resorption and subsequent formation on the ...Bone modeling and remodeling are governed by distinct biochemical processes that may hold unique opportunities for optimizing bone mass[1,2].Remodeling refers to the coupled resorption and subsequent formation on the bone surface,while modeling represents uncoupled formation or resorption.Mechanical loading is known to improve bone mass,though whether this occurs through modeling or remodeling(or by some combination)is unclear.Dynamic in vivo morphometry utilizing high resolution micro-CT and image registration has only recently become feasible and thus holds an untapped and expanding potential for understanding bone metabolism by quantifying and localizing formation/resorption and modeling/remodeling events.16-week-old mice were given 2 baseline weekly micro-CT scans of both tibiae prior to the initiation of daily unilateral loading(contralateral limb for nonloaded control).Weekly scanning and daily loading continued for 5 weeks.Registered images for each mouse in a global coordinate system revealed the time course of each voxel,and changes in bone mass were quantified as modeling or remodeling starting at the onset of loading.In cortical bone,after an initial response to loading in both regimes,modeling emerged as the dominant response.Loading effects were largest in areas of mechanical significance.For example,anabolic modeling on the periosteal surface of the half of the tibia in compression under axial load presented a strong effect of loading,whereas the same measure on the endosteal surface in the area in tension showed no difference.Similarly,in trabecular bone anabolic modeling was significantly increased with loading on trabecular plates but not rods(plates have been shown to be the major contributor to overall bone strength).The catabolic modeling response on the endosteal surface showed an interesting transition over time.Loading initially led to a significant suppression of catabolic modeling,but over time increased it to levels significantly beyond that of nonloaded controls.展开更多
Introduction Osteocytes are interconnected through numerous intercellular processes,forming extensive cell networks throughout the bone tissue[1]. It has been shown that osteocyte density is an important physiological...Introduction Osteocytes are interconnected through numerous intercellular processes,forming extensive cell networks throughout the bone tissue[1]. It has been shown that osteocyte density is an important physiological parameter,which decreases展开更多
Osteocytes in vivo are embedded in the mineralized extracellular bone matrix,where their cell bodies reside in the lacunae and are interconnected to neighboring osteocytes through numerous intercellular processes.The ...Osteocytes in vivo are embedded in the mineralized extracellular bone matrix,where their cell bodies reside in the lacunae and are interconnected to neighboring osteocytes through numerous intercellular processes.The 3-dimensional（3D）osteocyte network positioning and ability to communicate with other bone cells make osteocytes ideal mechanosensors of bone.Thus the role of osteocyte network and intercellular communication between osteocytes in response to mechanical stimulation may clarify the mechanisms behind normal bone adaptation to mechanical loading.We have been using intracellular calcium([Ca<sup>2+</sup>]<sub>i</sub>)as a ubiquitous real-time signaling indicator for studying mechanotransduction in osteocytic network展开更多
Hispanic Americans of Caribbean origin are a fast-growing subset of the US population, but there are no studies on bone density, microstructure and biomechanical integrity in this minority group. In this study, we aim...Hispanic Americans of Caribbean origin are a fast-growing subset of the US population, but there are no studies on bone density, microstructure and biomechanical integrity in this minority group. In this study, we aimed to compare Caucasian and Caribbean Hispanic postmenopausal American women with respect to these characteristics. Thirty-three Caribbean Hispanics were age-matched to thirty-three Caucasian postmenopausal women. At the lumbar spine, the Hispanic women had significantly lower areal bone mineral density （aBMD）. At the radius by high-resolution peripheral quantitative computed tomography （HR-pQCT）, there were minimal differences between Hispanic and Caucasian women. At the tibia, Hispanic women had lower trabecular volumetric bone density and trabecular number, and higher trabecular separation. Individual trabecula segmentation （ITS） analyses indicated that at the tibia, Hispanic women not only had significantly lower bone volume fraction, but also had significantly lower rod bone volume fraction, plate trabecular number, rod trabecular number and lower plate-plate, plate-rod and rod-rod junction densities compared to Caucasian women. The differences in bone quantity and quality contributed to lower whole bone stiffness at the radius, and both whole bone and trabecular bone stiffness at the tibia in Hispanic women. In conclusion, Hispanic women had poorer bone mechanical and microarchitectural properties than Caucasian women, especially at the load-bearing distal tibia.展开更多
We report here the application of a medicinally important plant Amaranthus spinosus for the synthesis of gold nanoparticles (AuNPs). Different concentrations of ethanolic leaf extract of the plant were reacted with aq...We report here the application of a medicinally important plant Amaranthus spinosus for the synthesis of gold nanoparticles (AuNPs). Different concentrations of ethanolic leaf extract of the plant were reacted with aqueous solution of HAuCl4·4H2O under mild reaction conditions. Synthesis of AuNPs was confirmed from the UV-Vis study of surface plasmon resonance property of the colloidal solution. Transmission electron microscopy (TEM) revealed particles as spherical and triangular in shape. X-ray diffraction (XRD) confirmed the crystalline nature of AuNPs with average size of 10.74 nm as determined by Debye-Scherrer’s Equation. Fourier transform infra-red (FT-IR) analysis of leaf extract and lyophilized AuNPs showed the presence of various functional groups present in diverse phytochemicals. Energy dispersive X-ray (EDX) of purified AuNPs confirmed the formation of AuNPs and surface adsorption of biomolecules. We further investigated the toxicity of the synthesized AuNPs and found non toxic to the cancer cell lines and could be used for biomedical applications.展开更多
This study concerns the synthesis of gel materials based on carbon nanotubes dispersed strontium-modified hydroxyapatite(Sr-HA)at different compositions obtained by sol–gel technology and their influence on human-bon...This study concerns the synthesis of gel materials based on carbon nanotubes dispersed strontium-modified hydroxyapatite(Sr-HA)at different compositions obtained by sol–gel technology and their influence on human-bone-marrow-derived mesenchymal stem cells.Furthermore,an evaluation of the influence of nanotubes and Strontium on physico-chemical,morphological,rheological and biological properties of hydroxyapatite gel was also performed.Morphological analysis(scanning electron microscopy)shows a homogeneous distribution of modified nanotubes in the ceramic matrix improving the bioactive properties of materials.The biological investigations proved that Sr-HA/carbon nanotube gel containing 0–20 mol(%)of Sr showed no toxic effect and promote the expression of early and late markers of osteogenic differentiation in cell culture performed in basal medium without osteogenic factors.Finally,the SrHA/carbon nanotube gels could have a good potential application as filler in bone repair and regeneration and may be used in the osteoporotic disease treatment.展开更多
基金supported by the Ningbo Science and Technology Project(No.2024J176)the Key Program of Science and Technology Innovation in Ningbo(No.2023 Z118)the Zhejiang Provincial Natural Science Foundation of China(No.LY22C190001)。
文摘Coccolithophores have unique ability of dual carbon fixation(photosynthesis and biocalcification)and can accumulate bioactive compounds effectively,thereby showing huge potential for CO_(2) bioremediation and simultaneous production of valueadded substances.However,biotechnological exploration of these microalgae is still very limited.In order to develop efficient cultivation strategies of these organisms,we tested the abilities of Chrysotila roscoffensis,a coccolithophore,to grow under mixotrophic and heterotrophic cultivation conditions.It was confirmed that only glycerol stimulated the cell growth of this microalga in the presence of light.To study the physiological significance of mixotrophy,we conducted cell culture experiments both autotrophically and mixotrophically,the only difference of which was optimal amount of glycerol was added under mixotrophic conditions.The results showed that the addition of glycerol substantially enhanced the lipids and monounsaturated fatty acids accumulation of C.roscoffensis,but imposed slight influences on the photosynthetic capacity,pigments content,polyunsaturated fatty acids content,and biocalcification.We concluded that mixotrophy might be an appropriate strategy for exploration of this species for production of high value molecules.
基金Supported by the National Natural Science Foundation of China(No.31902370)the Ningbo Public Welfare Science and Technology Program(No.2022S161)the Zhejiang Provincial Natural Science Foundation of China(No.LY22C190001)。
文摘Cyclotella cryptica,a model diatom known for its robust adaptability to variable salinity and temperature conditions,is a promising candidate for large-scale biotechnological applications.Nutrient availability,particularly nitrogen and phosphorus,plays a crucial role in the metabolic activities of microalgae,influencing its industrial utility.Exploring the relationship between these essential nutrients and both the yield and biochemical composition of this microalga is crucial for optimizing cultivation strategies.However,research focusing on the effects of nitrogen and phosphorus on C.cryptica remains limited.We investigated the impacts of varying concentrations of nitrate(0.25-3.96 mmol/L)and phosphate(14.4-229.6μmol/L)on C.cryptica culture by analyzing its growth performance,photosynthetic activity,biochemical composition,and biosilica deposition.Results indicate that C.cryptica exhibited enhanced growth,photosynthetic efficiency,and carotenoid production under higher nutrient concentrations.However,the effects of nitrate on macronutrients composition and fatty acids profile differed from those of phosphate.Specifically,increased nitrate levels resulted in higher concentrations of polyunsaturated fatty acids(PUFAs)at the expense of saturated fatty acids(SFAs),while increased phosphate levels were associated with increased PUFAs and reduced monounsaturated fatty acids(MUFAs).Additionally,biosilica deposition was weakened by elevated nitrate but enhanced by increased phosphate levels.This study improved our understanding of nutrient-mediated regulatory mechanisms in diatoms and contributed valuable data to the broader field of algal biotechnology.Moreover,these findings are expected to advance the development of tailored nutrient management strategies,thereby enhancing the industrial potential of C.cryptica.
基金supported by NIH R01 AR052461 and NIH R01 AR069148supported by a NSF Graduate Research Fellowship. A. E. M.supported by training grant T32 AR059038
文摘The vast osteocytic network is believed to orchestrate bone metabolic activity in response to mechanical stimuli through production of sclerostin, RANKL, and osteoprotegerin(OPG). However, the mechanisms of osteocyte mechanotransduction remain poorly understood. We've previously shown that osteocyte mechanosensitivity is encoded through unique intracellular calcium (Ca^(2+) ) dynamics. Here, by simultaneously monitoring Ca^(2+) and actin dynamics in single cells exposed to fluid shear flow, we detected actin network contractions immediately upon onset of flow-induced Ca^(2+) transients, which were facilitated by smooth muscle myosin and further confirmed in native osteocytes ex vivo. Actomyosin contractions have been linked to the secretion of extracellular vesicles(EVs), and our studies demonstrate that mechanical stimulation upregulates EV production in osteocytes through immunostaining for the secretory vesicle marker Lysosomal-associated membrane protein 1(LAMP1) and quantifying EV release in conditioned medium, both of which are blunted when Ca^(2+) signaling was inhibited by neomycin. Axial tibia compression was used to induce anabolic bone formation responses in mice, revealing upregulated LAMP1 and expected downregulation of sclerostin in vivo. This load-related increase in LAMP1 expression was inhibited in neomycin-injected mice compared to vehicle.Micro-computed tomography revealed significant load-related increases in both trabecular bone volume fraction and cortical thickness after two weeks of loading, which were blunted by neomycin treatment. In summary, we found mechanical stimulation of osteocytes activates Ca^(2+) -dependent contractions and enhances the production and release of EVs containing bone regulatory proteins. Further, blocking Ca^(2+) signaling significantly attenuates adaptation to mechanical loading in vivo, suggesting a critical role for Ca^(2+) -mediated signaling in bone adaptation.
基金This work was partially supported by grants from National Institutes of Health(AR051376,AR058004)
文摘Osteoporotic hip fracture is associated with significant trabecular bone loss, which is typically characterized as low bone density by dual-energy X-ray absorptiometry （DXA） and altered microstructure by micro-computed tomography （pCT）. Emerging morphological analysis techniques, e.g. individual trabecula segmentation （ITS）, can provide additional insights into changes in plate-like and rod-like trabeculae, two major micro- structural types serving different roles in determining bone strength. Using ITS, we evaluated trabecular microstructure of intertrochanteric bone cores obtained from 23 patients undergoing hip replacement surgery for intertrochanteric fracture and 22 cadaveric controls. Micro-finite element （~FE） analyses were performed to further understand how the abnormalities seen by ITS might translate into effects on bone strength. ITS analyses revealed that, near fracture site, plate-like trabeculae were seriously depleted in fracture patients, but trabecular rod volume was maintained. Besides, decreased plate area and rod length were observed in fracture patients. Fracture patients also showed decreased elastic moduli and shear moduli of trabecular bone. These results provided evidence that in intertrochanteric hip fracture, preferential loss of plate-like trabeculae led to more rod-like microstructure and deteriorated mechanical competence adjacent to the fracture site, which increased our understanding of the biomechanical pathogenesis of hip fracture in osteoporosis.
基金supported by National Natural Science Foundation of China(NSFC Nos.81601930 and U1613224)Natural Science Foundation of Guangxi(2016JJB140050)+1 种基金Research Grant Council of Hong Kong(HKU715213 and 17206916)Shenzhen Peacock Project
文摘Type 2 diabetes （T2D） is associated with systemic abnormal bone remodeling and bone loss. Meanwhile, abnormal subchondral bone remodeling induces cartilage degradation, resulting in osteoarthritis （OA）. Accordingly, we investigated alterations in subchondral bone remodeling, microstructure and strength in knees from T2D patients and their association with cartilage degradation. Tibial plateaus were collected from knee OA patients undergoing total knee arthroplasty and divided into non-diabetic （n---70） and diabetes （n = 51） groups. Tibial plateaus were also collected from cadaver donors （n = 20） and used as controls. Subchondral bone microstructure was assessed using micro-computed tomography. Bone strength was evaluated by micro-finite-element analysis. Cartilage degradation was estimated using histology. The expression of tartrate-resistant acidic phosphatase （TRAP）, osterix, and osteocalcin were calculated using immunohistochemistry. Osteoarthritis Research Society International （OARSI） scores of lateral tibial plateau did not differ between non-diabetic and diabetes groups, while higher OARSI scores on medial side were detected in diabetes group. Lower bone volume fraction and trabecular number and higher structure model index were found on both sides in diabetes group. These microstructural alterations translated into lower elastic modulus in diabetes group. Moreover, diabetes group had a larger number of TRAP~ osteoclasts and lower number of Osterix~ osteoprogenitors and Osteocalcin~ osteoblasts. T2D knees are characterized by abnormal subchondral bone remodeling and microstructural and mechanical impairments, which were associated with exacerbated cartilage degradation. In regions with intact cartilage the underlying bone still had abnormal remodeling in diabetes group, suggesting that abnormal bone remodeling may contribute to the early pathogenesis of T2D-associated knee OA.
基金Supported by the National Institute on Aging of the National Institutes of Health under Award No.P30AG010129the UC Davis Alzheimer's Disease Center Pilot Program,No.5R01NS100761-02 and No.1R01NS115860-01A1+1 种基金the Shriners Hospitals for Children Research Grants,No.85108-NCA-19 and No.85135-NCA-21the Shriners Hospitals for Children Postdoctoral Fellowship,No.84705-NCA-19.
文摘Mesenchymal stem/stromal cells(MSCs)are extensively studied as cell-therapy agents for neurological diseases.Recent studies consider exosomes secreted by MSCs as important mediators for MSCs’neuroprotective functions.Exosomes transfer functional molecules including proteins,lipids,metabolites,DNAs,and coding and non-coding RNAs from MSCs to their target cells.Emerging evidence shows that exosomal microRNAs(miRNAs)play a key role in the neuroprotective properties of these exosomes by targeting several genes and regulating various biological processes.Multiple exosomal miRNAs have been identified to have neuroprotective effects by promoting neurogenesis,neurite remodeling and survival,and neuroplasticity.Thus,exosomal miRNAs have significant therapeutic potential for neurological disorders such as stroke,traumatic brain injury,and neuroinflammatory or neurodegenerative diseases and disorders.This review discusses the neuroprotective effects of selected miRNAs(miR-21,miR-17-92,miR-133,miR-138,miR-124,miR-30,miR146a,and miR-29b)and explores their mechanisms of action and applications for the treatment of various neurological disease and disorders.It also provides an overview of state-of-the-art bioengineering approaches for isolating exosomes,optimizing their yield and manipulating the miRNA content of their cargo to improve their therapeutic potential.
基金supported by Shriner’s Hospital for Children(85108-NCA-19)the NIH(5R01NS100761)。
文摘Treatment for central nervous system(CNS)disorders is known to be limited by the low regenerative potential of neurons,and thus neurodegenerative insults became known as nearly irreversible ailments.Functional recovery for acquired CNS disorders,such as spinal cord injury(SCI),traumatic brain injury,ischemic stroke,Alzheimer’s disease,Parkinson’s disease,multiple sclerosis(MS),and for congenital CNS abnormalities,such as spina bifida,is not spontaneous and effective treatments are limited to non-existent.Research in the past decades has proven the regenerative potential of stem cells,especially that of mesenchymal stromal/stem cells(MSCs)from various origins,such as bone marrow,placenta,and adipose tissue.
基金supported by NIH(No.5R01NS100761-02,5R03HD091601-02)Shriners Hospital for Children research grants(No.87410-NCA-17 and 85119-NCA-18)March of Dimes Foundation(No.5FY1682)to AW
文摘The history: Myelomeningocele - also known as spina bifida- is a devastating congenital anomaly of the central nervoussystem that is caused by the malformation of the spinal cordand vertebral column during embryogenesis. Depending onthe location of the spina bifida lesion on the spine, patientssuffer from neurological dysfunction ranging from paresisand incontinence to complete paralysis. The current standardof care for spina bifida is in utero surgical repair of the defect,which has been shown to minimize the secondary deficits associatedwith this disorder (Adzick et al., 2011). Despite thesesuccesses, this approach does not reliably improve neurologicfunction of affected children. Several groups, including ourown, have performed studies aimed at augmenting the inutero surgical repair of spina bifida by applying principlesof stem cell and tissue engineering to provide an enhancedprotection of the exposed neural elements (Saadai et al., 2011,2013; Wang et al., 2015; Brown et al., 2016). The ultimategoal of these studies is to improve the neurologic function inpatients while maintaining the benefits of the existing fetalsurgical treatment.
基金the Science and Technology Commission fund of Shanghai Municipality (No. 09JC1411700)the Collaboration Projects of Development and Research from Basic Science of Stomatology of Shanghai(No. S30206-KF09)the Fund of Shanghai Jiaotong University School of Medicine (No. 09XJ21030)
文摘To explore the possible mechanism of osteogenesis for deciduous teeth stem cells (DTSCs) in vivo/ vitro, stem cells from goat deciduous teeth (SGDs) were firstly isolated, induced and transplanted into immunocompromised mice. The SGDs's mineralization pattern and osteogenesis were compared with bone marrow messenchymal stem cells (BMMSCs) from goats. SGDs have similar osteogenic differentiation pattern in vitro and bone-like tissue formation mechanism in vivo to BMMSCs; moreover SGDs have stronger alkaline phosphatase (ALP) gene expression and osteopontin (OPN) gene expression levels than BMMSCs; also SGDs can form more bone-like tissues than BMMSCs when cell-scaffold compounds are transplanted into immunocompromised mice. This pre-clinical study in a large-animal model confirms that DTSCs may be an appropriate source of stem cells in repairing bone defects with tissue engineering.
基金Supported by the National Natural Science Foundation of China (30570990, 30471059, 31171578)the "863" project (2008AA10Z153)+2 种基金the Key Research Plan of Heilongjiang Province (GA06B103-3)the Innovation Research Group of NEAU (CXT004)the Research Fund for the Doctoral Program of Higher Education of China (20102325120002)
文摘MicroRNAs （miRNAs） are a group of regulatory RNAs that regulate gene expression post-transcriptionally by the degradation or translational inhibition of their target messenger RNAs （mRNAs）. Regulation is accomplished when the 22-25 nucleotide miRNAs bind to complementary sequences in the 3＇-untranslated regions （UTR）. One barrier to miRNA research is to find target genes. Although computational target predictions have shed light on important aspects of microRNA target recognition, questions remain concerning the rates of false positives. In addition, we do not completely understand how microRNAs can recognize and regulate their targets. As such, experimental positive predictions and allow for an unbiased stu ap dy proaches are required, which can reflect in vivo processes, eliminating false of microRNA target recognition. In this review, we summarized experimental approaches that have been described for the identification and validation of mRNA targets associated with specific miRNAs.
基金the Shriners Hospital for Children Postdoctoral Research Fellowship award,No.84704-NCA-19UC Davis School of Medicine Dean’s Fellowship award and funding from the NIH,No.5R01NS100761-02 and No.R03HD091601-01+2 种基金the California Institute of Regenerative Medicine,No.PC1-08103 and No.CLIN1-11404Shriners Hospitals for Children,No.85120-NCA-16,No.85119-NCA-18,No.85108-NCA-19 and No.87200-NCA-19March of Dimes Foundation,No.5FY1682
文摘BACKGROUND Endothelial colony-forming cells(ECFCs)have been implicated in the process of vascularization,which includes vasculogenesis and angiogenesis.Vasculogenesis is a de novo formation of blood vessels,and is an essential physiological process that occurs during embryonic development and tissue regeneration.Angiogenesis is the growth of new capillaries from pre-existing blood vessels,which is observed both prenatally and postnatally.The placenta is an organ composed of a variety of fetal-derived cells,including ECFCs,and therefore has significant potential as a source of fetal ECFCs for tissue engineering.AIM To investigate the possibility of isolating clonal ECFCs from human early gestation chorionic villi(CV-ECFCs)of the placenta,and assess their potential for tissue engineering.METHODS The early gestation chorionic villus tissue was dissociated by enzyme digestion.Cells expressing CD31 were selected using magnetic-activated cell sorting,and plated in endothelial-specific growth medium.After 2-3 wks in culture,colonies displaying cobblestone-like morphology were manually picked using cloning cylinders.We characterized CV-ECFCs by flow cytometry,immunophenotyping,tube formation assay,and Dil-Ac-LDL uptake assay.Viral transduction of CVECFCs was performed using a Luciferase/tdTomato-containing lentiviral vector,and transduction efficiency was tested by fluorescent microscopy and flow cytometry.Compatibility of CV-ECFCs with a delivery vehicle was determined using an FDA approved,small intestinal submucosa extracellular matrix scaffold.RESULTS After four passages in 6-8 wks of culture,we obtained a total number of 1.8×107 CV-ECFCs using 100 mg of early gestational chorionic villus tissue.Immunophenotypic analyses by flow cytometry demonstrated that CV-ECFCs highly expressed the endothelial markers CD31,CD144,CD146,CD105,CD309,only partially expressed CD34,and did not express CD45 and CD90.CV-ECFCs were capable of acetylated low-density lipoprotein uptake and tube formation,similar to cord blood-derived ECFCs(CB-ECFCs).CV-ECFCs can be transduced with a Luciferase/tdTomato-containing lentiviral vector at a transduction efficiency of 85.1%.Seeding CV-ECFCs on a small intestinal submucosa extracellular matrix scaffold confirmed that CV-ECFCs were compatible with the biomaterial scaffold.CONCLUSION In summary,we established a magnetic sorting-assisted clonal isolation approach to derive CV-ECFCs.A substantial number of CV-ECFCs can be obtained within a short time frame,representing a promising novel source of ECFCs for fetal treatments.
文摘The purpose of this multicenter study was to evaluate the clinical performance of an ultrahigh molecular weight polyethylene (UHMWPE) fiber cable for re-attachment of the osteotomized greater trochanter in hip surgery. Included in the study were 85 hips that had undergone surgery with greater trochanter osteotomy, including 50 hip arthroplasty procedures and 35 hip osteotomies. The osteotomized greater trochanter was reattached using one or more UHMWPE fiber cables. The bone union and displacement of the greater trochanter were assessed in radiographs for up to 12 months after surgery. Non-union of the osteotomy site occurred in 4.7% of the cases. In approximately 90% of the cases, displacement was less than 2 mm at up to 12 months after surgery. The UHMWPE fiber cable was a good biomaterial for reattaching the osteotomized greater trochanter and may also be an option for osteosynthesis procedures.
基金supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases ( R01 AR069148)
文摘Bone modeling and remodeling are governed by distinct biochemical processes that may hold unique opportunities for optimizing bone mass[1,2].Remodeling refers to the coupled resorption and subsequent formation on the bone surface,while modeling represents uncoupled formation or resorption.Mechanical loading is known to improve bone mass,though whether this occurs through modeling or remodeling(or by some combination)is unclear.Dynamic in vivo morphometry utilizing high resolution micro-CT and image registration has only recently become feasible and thus holds an untapped and expanding potential for understanding bone metabolism by quantifying and localizing formation/resorption and modeling/remodeling events.16-week-old mice were given 2 baseline weekly micro-CT scans of both tibiae prior to the initiation of daily unilateral loading(contralateral limb for nonloaded control).Weekly scanning and daily loading continued for 5 weeks.Registered images for each mouse in a global coordinate system revealed the time course of each voxel,and changes in bone mass were quantified as modeling or remodeling starting at the onset of loading.In cortical bone,after an initial response to loading in both regimes,modeling emerged as the dominant response.Loading effects were largest in areas of mechanical significance.For example,anabolic modeling on the periosteal surface of the half of the tibia in compression under axial load presented a strong effect of loading,whereas the same measure on the endosteal surface in the area in tension showed no difference.Similarly,in trabecular bone anabolic modeling was significantly increased with loading on trabecular plates but not rods(plates have been shown to be the major contributor to overall bone strength).The catabolic modeling response on the endosteal surface showed an interesting transition over time.Loading initially led to a significant suppression of catabolic modeling,but over time increased it to levels significantly beyond that of nonloaded controls.
基金supported by US National Institute of Health grants (National Institute of Arthritis and Musculoskeletal and Skin Diseases) R21 AR052417,R01 AR1R052461,and RC1 AR058453
文摘Introduction Osteocytes are interconnected through numerous intercellular processes,forming extensive cell networks throughout the bone tissue[1]. It has been shown that osteocyte density is an important physiological parameter,which decreases
基金supported by the US National Institutes of Health grants R21 AR052417,R01 AR052461,RC1 AR058453(XEG),and R01 AR054385(LW)
文摘Osteocytes in vivo are embedded in the mineralized extracellular bone matrix,where their cell bodies reside in the lacunae and are interconnected to neighboring osteocytes through numerous intercellular processes.The 3-dimensional（3D）osteocyte network positioning and ability to communicate with other bone cells make osteocytes ideal mechanosensors of bone.Thus the role of osteocyte network and intercellular communication between osteocytes in response to mechanical stimulation may clarify the mechanisms behind normal bone adaptation to mechanical loading.We have been using intracellular calcium([Ca<sup>2+</sup>]<sub>i</sub>)as a ubiquitous real-time signaling indicator for studying mechanotransduction in osteocytic network
基金supported by NIH Grants R01 AR051376 (XEG), NIH R01 AR058004 (XEG, ES), NIH U01 AR055968 (ES)the Thomas L.Kempner and Katheryn C.Patterson Foundation
文摘Hispanic Americans of Caribbean origin are a fast-growing subset of the US population, but there are no studies on bone density, microstructure and biomechanical integrity in this minority group. In this study, we aimed to compare Caucasian and Caribbean Hispanic postmenopausal American women with respect to these characteristics. Thirty-three Caribbean Hispanics were age-matched to thirty-three Caucasian postmenopausal women. At the lumbar spine, the Hispanic women had significantly lower areal bone mineral density （aBMD）. At the radius by high-resolution peripheral quantitative computed tomography （HR-pQCT）, there were minimal differences between Hispanic and Caucasian women. At the tibia, Hispanic women had lower trabecular volumetric bone density and trabecular number, and higher trabecular separation. Individual trabecula segmentation （ITS） analyses indicated that at the tibia, Hispanic women not only had significantly lower bone volume fraction, but also had significantly lower rod bone volume fraction, plate trabecular number, rod trabecular number and lower plate-plate, plate-rod and rod-rod junction densities compared to Caucasian women. The differences in bone quantity and quality contributed to lower whole bone stiffness at the radius, and both whole bone and trabecular bone stiffness at the tibia in Hispanic women. In conclusion, Hispanic women had poorer bone mechanical and microarchitectural properties than Caucasian women, especially at the load-bearing distal tibia.
文摘We report here the application of a medicinally important plant Amaranthus spinosus for the synthesis of gold nanoparticles (AuNPs). Different concentrations of ethanolic leaf extract of the plant were reacted with aqueous solution of HAuCl4·4H2O under mild reaction conditions. Synthesis of AuNPs was confirmed from the UV-Vis study of surface plasmon resonance property of the colloidal solution. Transmission electron microscopy (TEM) revealed particles as spherical and triangular in shape. X-ray diffraction (XRD) confirmed the crystalline nature of AuNPs with average size of 10.74 nm as determined by Debye-Scherrer’s Equation. Fourier transform infra-red (FT-IR) analysis of leaf extract and lyophilized AuNPs showed the presence of various functional groups present in diverse phytochemicals. Energy dispersive X-ray (EDX) of purified AuNPs confirmed the formation of AuNPs and surface adsorption of biomolecules. We further investigated the toxicity of the synthesized AuNPs and found non toxic to the cancer cell lines and could be used for biomedical applications.
基金supported through funds provided by the PNR-CNR Aging Program 2012-2014.
文摘This study concerns the synthesis of gel materials based on carbon nanotubes dispersed strontium-modified hydroxyapatite(Sr-HA)at different compositions obtained by sol–gel technology and their influence on human-bone-marrow-derived mesenchymal stem cells.Furthermore,an evaluation of the influence of nanotubes and Strontium on physico-chemical,morphological,rheological and biological properties of hydroxyapatite gel was also performed.Morphological analysis(scanning electron microscopy)shows a homogeneous distribution of modified nanotubes in the ceramic matrix improving the bioactive properties of materials.The biological investigations proved that Sr-HA/carbon nanotube gel containing 0–20 mol(%)of Sr showed no toxic effect and promote the expression of early and late markers of osteogenic differentiation in cell culture performed in basal medium without osteogenic factors.Finally,the SrHA/carbon nanotube gels could have a good potential application as filler in bone repair and regeneration and may be used in the osteoporotic disease treatment.
