Cre/loxP technology has been widely used to study cell type-specific functions of genes. Proper interpretation of such data critically depends on a clear understanding of the tissue specificity of Cre expression. The ...Cre/loxP technology has been widely used to study cell type-specific functions of genes. Proper interpretation of such data critically depends on a clear understanding of the tissue specificity of Cre expression. The Dmpl- Cre mouse, expressing Cre from a 14-kb DNA fragment of the mouse Dmpl gene, has become a common tool for studying gene function in osteocytes, but the presumed cell specificity is yet to be fully established. By using the Ai9 reporter line that expresses a red fluorescent protein upon Cre recombination, we find that in 2-month-old mice, Dmpl-Cre targets not only osteocytes within the bone matrix but also osteoblasts on the bone surface and preosteoblasts at the metaphyseal chondro-osseous junction. In the bone marrow, Cre activity is evident in certain stromal cells adjacent to the blood vessels, but not in adipocytes. Outside the skeleton, Dmpl-Cre marks not only the skeletal muscle fibers, certain cells in the cerebellum and the hindbrain but also gastric and intestinal mesenchymal cells that express Pdgfra. Confirming the utility of Dmpl-Cre in the gastrointestinal mesenchyme, deletion of Bmprla with Dmpl-Cre causes numerous large polyps along the gastrointestinal tract, consistent with prior work involving inhibition of BMP signaling. Thus, caution needs to be exercised when using Dmpl-Cre because it targets not only the osteoblast lineage at an earlier stage than previously appreciated, but also a number of non-skeletal cell types.展开更多
Thyroid hormone excess secondary to global type 3 deiodinase(DIO3)deficiency leads to increased locomotor activity and reduced adiposity,but also to concurrent alterations in parameters of the leptin-melanocortin syst...Thyroid hormone excess secondary to global type 3 deiodinase(DIO3)deficiency leads to increased locomotor activity and reduced adiposity,but also to concurrent alterations in parameters of the leptin-melanocortin system that would predict obesity.To distinguish the underlying contributions to the energy balance phenotype of Dlo3 deficiency,we generated mice with thyroid hormone excess targeted to pro-opiomelanocortin(POMC)-expressing cells via cell-specific DIO3 inactivation.These mice exhibit a male-specific phenotype of reduced hypothalamic Pomc expression,hyperphagia,and increased activity in brown adipose tissue,with adiposity and serum levels of leptin and thyroid hormones remained normal.These male mice also manifest a marked and widespread hypothalamic reduction in the expression of bone morphogenetic receptor 1a(BMPR1A),which has been shown to cause similar phenotypes when inactivated in PoMC-expressing cells.Our results indicate that developmental overexposure to thyroid hormone in PoMC-expressing cells programs energy balance mechanisms in a sexually dimorphic manner by suppressing adult hypothalamic BMPR1A expression.展开更多
Background Bone morphogenetic protein receptor type 1A(BMPR1A)is responsible for two individual Mendelian diseases:juvenile polyposis syndrome and hereditary mixed polyposis syndrome 2,which have overlapping phenotype...Background Bone morphogenetic protein receptor type 1A(BMPR1A)is responsible for two individual Mendelian diseases:juvenile polyposis syndrome and hereditary mixed polyposis syndrome 2,which have overlapping phenotypes.This study aimed to elucidate whether these two syndromes are just two subtypes of a single syndrome rather than two isolated syndromes.Methods We sequenced the BMPR1A gene in 186 patients with polyposis and colorectal cancer,and evaluated the clinicopathological features and phenotypes of the probands and their available relatives with BMPR1A mutations.Results BMPR1A germline mutations were found in six probands and their three available relatives.The numbers of frameshift,nonsense,splice-site,andmissensemutations were one,one,two,and two,respectively;two of the sixmutations were novel.Typical juvenile polyps were found in only three patients.Two patients had colorectal cancer rather than any polyps.Conclusions Diseases in BMPR1A germline mutation carriers vary from mixed polyposis to sole colorectal cancer,and typical juvenile polyps do not always occur in these carriers.The variety of phenotypes reflected the features of BMPR1Amutation carriers,which should be recognized as a spectrum of one syndrome.Genetic testing may be a good approach to identifying BMPR1A-related syndromes.展开更多
骨形态发生蛋白受体1B(Bone morphogenetic protein receptor 1B,BMPR1B)是一种重要的跨膜受体蛋白,主要参与转化生长因子β(TGF-β)通路,其在调控成骨分化、细胞扩散以及卵巢卵泡发育等过程中起重要作用,并直接影响如绵羊等动物的繁殖...骨形态发生蛋白受体1B(Bone morphogenetic protein receptor 1B,BMPR1B)是一种重要的跨膜受体蛋白,主要参与转化生长因子β(TGF-β)通路,其在调控成骨分化、细胞扩散以及卵巢卵泡发育等过程中起重要作用,并直接影响如绵羊等动物的繁殖性状。绵羊BMPR1B基因发生A746G突变(命名为FecB突变),导致第249位氨基酸由谷氨酰胺(Q)转变为精氨酸(R),进而使得绵羊排卵数和产羔数显著增加,因此BMPR1B成为目前最受关注的绵羊多羔主效基因。论文就绵羊BMPR1B基因定位、功能机制研究进展及其对高繁殖力绵羊的影响进行了综述,同时也对BMPR1B功能研究中一些亟待解决的问题展开了讨论。展开更多
Juvenile polyposis syndrome is a rare autosomal dominant syndrome characterized by multiple distinct juvenile polyps in the gastrointestinal tract and an increased risk of colorectal cancer.The cumulative life-time ri...Juvenile polyposis syndrome is a rare autosomal dominant syndrome characterized by multiple distinct juvenile polyps in the gastrointestinal tract and an increased risk of colorectal cancer.The cumulative life-time risk of colorectal cancer is 39% and the relative risk is 34.Juvenile polyps have a distinctive histology characterized by an abundance of edematous lamina propria with inflammatory cells and cystically dilated glands lined by cuboidal to columnar epithelium with reactive changes.Clinically,juvenile polyposis syndrome is defined by the presence of 5 or more juvenile polyps in the colorectum,juvenile polyps throughout the gastrointestinal tract or any number of juvenile polyps and a positive family history of juvenile polyposis.In about 50%-60% of patients diagnosed with juvenile polyposis syndrome a germline mutation in the SMAD4 or BMPR1A gene is found.Both genes play a role in the BMP/TGF-beta signalling pathway.It has been suggested that cancer in juvenile polyposis may develop through the socalled "landscaper mechanism" where an abnormal stromal environment leads to neoplastic transformation of the adjacent epithelium and in the end invasive carcinoma.Recognition of this rare disorder is important for patients and their families with regard to treatment,follow-up and screening of at risk individuals.Each clinician confronted with the diagnosis of a juvenile polyp should therefore consider the possibility of juvenile polyposis syndrome.In addition,juvenile polyposis syndrome provides a unique model to study colorectal cancer pathogenesis in general and gives insight in the molecular genetic basis of cancer.This review discusses clinical manifestations,genetics,pathogenesis and management of juvenile polyposis syndrome.展开更多
基金supported by NIH grants AR060456 and AR055923(FL)supported by NIH DK105129,DK094989,by DK052574 to the Washington University Digestive Core Centers(DDRCC)+6 种基金by the pre-Program Project Award from the Siteman Cancer Center Investment Programsupported by the NIGMS cell and Molecular Biology Training Grant(GM007067)supported by the NIH funded George O’Brien Center for Kidney Disease Research(P30DK079333)Kidney translational Research Core and the Renal Division at the Washington University School of Medicinesupported by the Alafi Neuroimaging Laboratorythe Hope Center for Neurological DisordersNIH Shared Instrumentation Grant(S10 RR0227552)to Washington University
文摘Cre/loxP technology has been widely used to study cell type-specific functions of genes. Proper interpretation of such data critically depends on a clear understanding of the tissue specificity of Cre expression. The Dmpl- Cre mouse, expressing Cre from a 14-kb DNA fragment of the mouse Dmpl gene, has become a common tool for studying gene function in osteocytes, but the presumed cell specificity is yet to be fully established. By using the Ai9 reporter line that expresses a red fluorescent protein upon Cre recombination, we find that in 2-month-old mice, Dmpl-Cre targets not only osteocytes within the bone matrix but also osteoblasts on the bone surface and preosteoblasts at the metaphyseal chondro-osseous junction. In the bone marrow, Cre activity is evident in certain stromal cells adjacent to the blood vessels, but not in adipocytes. Outside the skeleton, Dmpl-Cre marks not only the skeletal muscle fibers, certain cells in the cerebellum and the hindbrain but also gastric and intestinal mesenchymal cells that express Pdgfra. Confirming the utility of Dmpl-Cre in the gastrointestinal mesenchyme, deletion of Bmprla with Dmpl-Cre causes numerous large polyps along the gastrointestinal tract, consistent with prior work involving inhibition of BMP signaling. Thus, caution needs to be exercised when using Dmpl-Cre because it targets not only the osteoblast lineage at an earlier stage than previously appreciated, but also a number of non-skeletal cell types.
基金We are grateful for the technical support of the Molecular Phenotyping,Histopathology and Histomorphometry,Confocal Microscopy,and Physiology Core facilities at MaineHealth Institute for Research.These core facilities are supported by grants P30GM106391,U54GM115516,and P20GM121301 from the National Institute of General Medical SciencesThis work was supported by grant DK095908(to A.H.)from the National Institute of Diabetes,Digestive and Kidney Diseases,National Institutes of Health,USA.
文摘Thyroid hormone excess secondary to global type 3 deiodinase(DIO3)deficiency leads to increased locomotor activity and reduced adiposity,but also to concurrent alterations in parameters of the leptin-melanocortin system that would predict obesity.To distinguish the underlying contributions to the energy balance phenotype of Dlo3 deficiency,we generated mice with thyroid hormone excess targeted to pro-opiomelanocortin(POMC)-expressing cells via cell-specific DIO3 inactivation.These mice exhibit a male-specific phenotype of reduced hypothalamic Pomc expression,hyperphagia,and increased activity in brown adipose tissue,with adiposity and serum levels of leptin and thyroid hormones remained normal.These male mice also manifest a marked and widespread hypothalamic reduction in the expression of bone morphogenetic receptor 1a(BMPR1A),which has been shown to cause similar phenotypes when inactivated in PoMC-expressing cells.Our results indicate that developmental overexposure to thyroid hormone in PoMC-expressing cells programs energy balance mechanisms in a sexually dimorphic manner by suppressing adult hypothalamic BMPR1A expression.
基金supported by National Key R&D Program of China[no.2017YFC1308800]National Natural Science Foundation of China[no.81870455]Discipline Climbing Program 234 of Changhai Hospital[no.2019YXK036].
文摘Background Bone morphogenetic protein receptor type 1A(BMPR1A)is responsible for two individual Mendelian diseases:juvenile polyposis syndrome and hereditary mixed polyposis syndrome 2,which have overlapping phenotypes.This study aimed to elucidate whether these two syndromes are just two subtypes of a single syndrome rather than two isolated syndromes.Methods We sequenced the BMPR1A gene in 186 patients with polyposis and colorectal cancer,and evaluated the clinicopathological features and phenotypes of the probands and their available relatives with BMPR1A mutations.Results BMPR1A germline mutations were found in six probands and their three available relatives.The numbers of frameshift,nonsense,splice-site,andmissensemutations were one,one,two,and two,respectively;two of the sixmutations were novel.Typical juvenile polyps were found in only three patients.Two patients had colorectal cancer rather than any polyps.Conclusions Diseases in BMPR1A germline mutation carriers vary from mixed polyposis to sole colorectal cancer,and typical juvenile polyps do not always occur in these carriers.The variety of phenotypes reflected the features of BMPR1Amutation carriers,which should be recognized as a spectrum of one syndrome.Genetic testing may be a good approach to identifying BMPR1A-related syndromes.
文摘骨形态发生蛋白受体1B(Bone morphogenetic protein receptor 1B,BMPR1B)是一种重要的跨膜受体蛋白,主要参与转化生长因子β(TGF-β)通路,其在调控成骨分化、细胞扩散以及卵巢卵泡发育等过程中起重要作用,并直接影响如绵羊等动物的繁殖性状。绵羊BMPR1B基因发生A746G突变(命名为FecB突变),导致第249位氨基酸由谷氨酰胺(Q)转变为精氨酸(R),进而使得绵羊排卵数和产羔数显著增加,因此BMPR1B成为目前最受关注的绵羊多羔主效基因。论文就绵羊BMPR1B基因定位、功能机制研究进展及其对高繁殖力绵羊的影响进行了综述,同时也对BMPR1B功能研究中一些亟待解决的问题展开了讨论。
文摘Juvenile polyposis syndrome is a rare autosomal dominant syndrome characterized by multiple distinct juvenile polyps in the gastrointestinal tract and an increased risk of colorectal cancer.The cumulative life-time risk of colorectal cancer is 39% and the relative risk is 34.Juvenile polyps have a distinctive histology characterized by an abundance of edematous lamina propria with inflammatory cells and cystically dilated glands lined by cuboidal to columnar epithelium with reactive changes.Clinically,juvenile polyposis syndrome is defined by the presence of 5 or more juvenile polyps in the colorectum,juvenile polyps throughout the gastrointestinal tract or any number of juvenile polyps and a positive family history of juvenile polyposis.In about 50%-60% of patients diagnosed with juvenile polyposis syndrome a germline mutation in the SMAD4 or BMPR1A gene is found.Both genes play a role in the BMP/TGF-beta signalling pathway.It has been suggested that cancer in juvenile polyposis may develop through the socalled "landscaper mechanism" where an abnormal stromal environment leads to neoplastic transformation of the adjacent epithelium and in the end invasive carcinoma.Recognition of this rare disorder is important for patients and their families with regard to treatment,follow-up and screening of at risk individuals.Each clinician confronted with the diagnosis of a juvenile polyp should therefore consider the possibility of juvenile polyposis syndrome.In addition,juvenile polyposis syndrome provides a unique model to study colorectal cancer pathogenesis in general and gives insight in the molecular genetic basis of cancer.This review discusses clinical manifestations,genetics,pathogenesis and management of juvenile polyposis syndrome.
