Streptococcus suis serotype 2(SS2)is a zoonotic pathogen that can cause acute infection,such as septicemia in pigs and streptococcal toxic shock-like syndrome(STSLS)in humans,indicating that SS2 can evade innate immun...Streptococcus suis serotype 2(SS2)is a zoonotic pathogen that can cause acute infection,such as septicemia in pigs and streptococcal toxic shock-like syndrome(STSLS)in humans,indicating that SS2 can evade innate immunity.Macrophages perform essential antimicrobial functions in the innate immune system by engulfing and killing pathogens.Previously,a dna K mutant strain that showed impaired phagocytosis resistance ability was screened from the transposon mutant library of SS2,but the specific mechanism is unclear.In this study,we further demonstrated that DnaK was required for SS2 to be antiphagocytosed by macrophages and survive in adverse environments.A mouse challenge experiment indicated that DnaK promoted bacteremia and systemic dissemination of SS2,enhancing bacterial pathogenicity.Western blot and immunofluorescence results indicated that DnaK could be secreted by SS2 and was able to enter RAW264.7 macrophages.Then,the endocytic receptor LRP1 regulated by DnaK was identified through RNA sequencing(RNA-Seq).We found that DnaK decreased both the mRNA and protein levels of LRP1.Knockdown of the LRP1β-chain(LRP1β)significantly decreased the phagocytosis rate of the SS2 strain ZY05719,suggesting that LRP1 is a phagocytic receptor of SS2.Furthermore,inhibitor treatment assays revealed that DnaK decreased LRP1 protein levels through the transcription factor PPARγand the ubiquitin-proteasome system.In summary,DnaK contributes to the phagocytosis resistance of SS2 by decreasing LRP1 protein levels in macrophages,providing new insights into the antiphagocytosis mechanisms of SS2 and helping to understand its pathogenesis.展开更多
血脑屏障(blood-brain barrier,BBB)是介于外周和中枢神经系统之间的一道生理屏障,对维持中枢神经系统的稳态起着重要作用。研究表明,血脑屏障与阿尔茨海默病(Alzheimer’s disease,AD)的发生发展密切相关。该文重点论述血脑屏障晚期糖...血脑屏障(blood-brain barrier,BBB)是介于外周和中枢神经系统之间的一道生理屏障,对维持中枢神经系统的稳态起着重要作用。研究表明,血脑屏障与阿尔茨海默病(Alzheimer’s disease,AD)的发生发展密切相关。该文重点论述血脑屏障晚期糖基化终产物受体(receptor for advanced glycation end products,RAGE)/低密度脂蛋白受体相关蛋白1(low density lipoprotein receptor-related protein 1,LRP1)受体转运系统及以血脑屏障为核心组分的神经血管单元(neurovascular unit,NVU)介导的中枢β-淀粉样蛋白(β-amyloid protein,Aβ)水平调控与AD发病机制的关系,为AD防治提供新思路。展开更多
目的:探讨低密度脂蛋白受体相关蛋白1(low density lipoprotein receptor-related protein 1,LRP1)在肺癌细胞中的表达水平及其生物学意义。方法:常规培养人类肺癌A549细胞,RT-PCR法检测A549细胞中LRP1的mRNA水平。构建针对LRP1的siRNA...目的:探讨低密度脂蛋白受体相关蛋白1(low density lipoprotein receptor-related protein 1,LRP1)在肺癌细胞中的表达水平及其生物学意义。方法:常规培养人类肺癌A549细胞,RT-PCR法检测A549细胞中LRP1的mRNA水平。构建针对LRP1的siRNA感染细胞,利用绿色荧光标记载体,通过荧光显微镜观察感染效率,利用RT-PCR检测敲减效率,Western blot检测LRP1表达水平变化。选用A549/LRP1 siRNA细胞系进行功能实验,利用CCK-8实验检测细胞增殖能力的变化,划痕实验检测细胞迁移能力的变化,Transwell侵袭小室实验检测细胞侵袭能力的变化。结果:从定量PCR结果可以看出,A549细胞中,相对于NC组,KD组LRP1基因敲减效率为77.7%,KD组细胞中LRP1的mRNA水平明显低于NC组,差异具有统计学意义(P<0.05);Western blot检测结果显示,KD组LRP1表达水平相对于NC组显著下调。CCK-8检测结果表明相对于NC组,KD组于Day 5的细胞增殖倍数显著下降,差异具有统计学意义(P<0.05)。划痕实验结果显示,相比NC组,KD组细胞划痕8小时、24小时迁移率明显降低,差异具有统计学意义(P<0.05)。Transwell侵袭实验结果显示,在侵袭小室内孵育24 h后KD组细胞侵袭转移率明显降低,差异具有统计学意义(P<0.05)。结论:LRP1对于肺癌A549细胞的生物学功能起着重要作用。下调LRP1能够抑制A549细胞的增殖、迁移及侵袭能力。对于LRP1分子上下游信号通路研究,在肺癌的诊断与治疗领域有一定的临床参考价值。展开更多
Background: LDL receptor-related protein-1(LRP1) is a cell-surface receptor that functions in diverse physiological pathways. We previously demonstrated that hepatocyte-specific LRP1 deficiency(hLRP1KO) promotes diet-...Background: LDL receptor-related protein-1(LRP1) is a cell-surface receptor that functions in diverse physiological pathways. We previously demonstrated that hepatocyte-specific LRP1 deficiency(hLRP1KO) promotes diet-induced insulin resistance and increases hepatic gluconeogenesis in mice. However, it remains unclear whether LRP1 regulates hepatic glycogenesis.Methods: Insulin signaling, glycogenic gene expression, and glycogen content were assessed in mice and HepG2 cells. The pcDNA 3.1 plasmid and adeno-associated virus serotype 8 vector(AAV8) were used to overexpress the truncated β-chain(βΔ) of LRP1 both in vitro and in vivo.Results: On a normal chow diet, hLRP1KO mice exhibited impaired insulin signaling and decreased glycogen content. Moreover, LRP1 expression in HepG2 cells was significantly repressed by palmitate in a dose-and time-dependent manner. Both LRP1 knockdown and palmitate treatment led to reduced phosphorylation of Akt and GSK3β, increased levels of phosphorylated glycogen synthase(GYS), and diminished glycogen synthesis in insulin-stimulated HepG2 cells, which was restored by exogenous expression of the βΔ-chain. By contrast, AAV8-mediated hepatic βΔ-chain overexpression significantly improved the insulin signaling pathway, thus activating glycogenesis and enhancing glycogen storage in the livers of high-fat diet(HFD)-fed mice.Conclusion: Our data revealed that LRP1, especially its β-chain, facilitates hepatic glycogenesis by improving the insulin signaling pathway, suggesting a new therapeutic strategy for hepatic insulin resistance-related diseases.展开更多
Psoriasis is an incurable chronic inflammatory disease that requires new interventions.Here,we found that fibroblasts exacerbate psoriasis progression by promoting macrophage recruitment via CCL2 secretion by single-c...Psoriasis is an incurable chronic inflammatory disease that requires new interventions.Here,we found that fibroblasts exacerbate psoriasis progression by promoting macrophage recruitment via CCL2 secretion by single-cell multi-omics analysis.The natural small molecule celastrol was screened to interfere with the secretion of CCL2 by fibroblasts and improve the psoriasis-like symptoms in both murine and cynomolgus monkey models.Mechanistically,celastrol directly bound to the low-density lipoprotein receptor-related protein 1(LRP1)β-chain and abolished its binding to the transcription factor c-Jun in the nucleus,which in turn inhibited CCL2 production by skin fibroblasts,blocked fibroblast-macrophage crosstalk,and ameliorated psoriasis progression.Notably,fibroblast-specific LRP1 knockout mice exhibited a significant reduction in psoriasis like inflammation.Taken together,from clinical samples and combined with various mouse models,we revealed the pathogenesis of psoriasis from the perspective of fibroblast-macrophage crosstalk,and provided a foundation for LRP1 as a novel potential target for psoriasis treatment.展开更多
The relationship between chronic psychological stress and tumorigenesis has been well defined in epidemiological studies;however, the underlying mechanism remains underexplored. In this study, we discovered that impai...The relationship between chronic psychological stress and tumorigenesis has been well defined in epidemiological studies;however, the underlying mechanism remains underexplored. In this study, we discovered that impaired macrophage phagocytosis contributed to the psychological stressevoked tumor susceptibility, and the stress hormone glucocorticoid(GC) was identified as a principal detrimental factor. Mechanistically, GC disturbed the balance of the "eat me" signal receptor(low-density lipoprotein receptor-related protein-1, LRP1) and the "don’t eat me" signal receptor(signal regulatory protein alpha, SIRPa). Further analysis revealed that GC led to a direct, glucocorticoid receptor(GR)-dependent trans-repression of LRP1 expression, and the repressed LRP1, in turn, resulted in the elevatedgene level of SIRPa by down-regulating mi RNA-4695-3 p. These data collectively demonstrate that stress induces the imbalance of the LRP1/SIRPa axis and entails the disturbance of tumor cell clearance by macrophages. Our findings provide the mechanistic insight into psychological stress-evoked tumor susceptibility and indicate that the balance of LRP1/SIRPa axis may serve as a potential therapeutic strategy for tumor treatment.展开更多
基金funded by the National Key Research and Development Program of China(2021YFD1800400)the National Natural Science Foundation of China(32373018)+2 种基金Jiangsu Agriculture Science and Technology Innovation Fund,China(CX(23)1029)the Excellent Research Innovation Team in Universities in Anhui Province,China(2022AH010088)the Shennong Scholar Project of Anhui Agricultural University,China(rc392101)。
文摘Streptococcus suis serotype 2(SS2)is a zoonotic pathogen that can cause acute infection,such as septicemia in pigs and streptococcal toxic shock-like syndrome(STSLS)in humans,indicating that SS2 can evade innate immunity.Macrophages perform essential antimicrobial functions in the innate immune system by engulfing and killing pathogens.Previously,a dna K mutant strain that showed impaired phagocytosis resistance ability was screened from the transposon mutant library of SS2,but the specific mechanism is unclear.In this study,we further demonstrated that DnaK was required for SS2 to be antiphagocytosed by macrophages and survive in adverse environments.A mouse challenge experiment indicated that DnaK promoted bacteremia and systemic dissemination of SS2,enhancing bacterial pathogenicity.Western blot and immunofluorescence results indicated that DnaK could be secreted by SS2 and was able to enter RAW264.7 macrophages.Then,the endocytic receptor LRP1 regulated by DnaK was identified through RNA sequencing(RNA-Seq).We found that DnaK decreased both the mRNA and protein levels of LRP1.Knockdown of the LRP1β-chain(LRP1β)significantly decreased the phagocytosis rate of the SS2 strain ZY05719,suggesting that LRP1 is a phagocytic receptor of SS2.Furthermore,inhibitor treatment assays revealed that DnaK decreased LRP1 protein levels through the transcription factor PPARγand the ubiquitin-proteasome system.In summary,DnaK contributes to the phagocytosis resistance of SS2 by decreasing LRP1 protein levels in macrophages,providing new insights into the antiphagocytosis mechanisms of SS2 and helping to understand its pathogenesis.
文摘血脑屏障(blood-brain barrier,BBB)是介于外周和中枢神经系统之间的一道生理屏障,对维持中枢神经系统的稳态起着重要作用。研究表明,血脑屏障与阿尔茨海默病(Alzheimer’s disease,AD)的发生发展密切相关。该文重点论述血脑屏障晚期糖基化终产物受体(receptor for advanced glycation end products,RAGE)/低密度脂蛋白受体相关蛋白1(low density lipoprotein receptor-related protein 1,LRP1)受体转运系统及以血脑屏障为核心组分的神经血管单元(neurovascular unit,NVU)介导的中枢β-淀粉样蛋白(β-amyloid protein,Aβ)水平调控与AD发病机制的关系,为AD防治提供新思路。
基金financially supported by the National Natural Science Foundation of China (Grant No. 82270854)the Natural Science Foundation of Chongqing+2 种基金China (No. cstc2020jcyj-msxm X0408)the Program for Youth Innovation in Future MedicineChongqing Medical University (No. W0162) to Yinyuan Ding。
文摘Background: LDL receptor-related protein-1(LRP1) is a cell-surface receptor that functions in diverse physiological pathways. We previously demonstrated that hepatocyte-specific LRP1 deficiency(hLRP1KO) promotes diet-induced insulin resistance and increases hepatic gluconeogenesis in mice. However, it remains unclear whether LRP1 regulates hepatic glycogenesis.Methods: Insulin signaling, glycogenic gene expression, and glycogen content were assessed in mice and HepG2 cells. The pcDNA 3.1 plasmid and adeno-associated virus serotype 8 vector(AAV8) were used to overexpress the truncated β-chain(βΔ) of LRP1 both in vitro and in vivo.Results: On a normal chow diet, hLRP1KO mice exhibited impaired insulin signaling and decreased glycogen content. Moreover, LRP1 expression in HepG2 cells was significantly repressed by palmitate in a dose-and time-dependent manner. Both LRP1 knockdown and palmitate treatment led to reduced phosphorylation of Akt and GSK3β, increased levels of phosphorylated glycogen synthase(GYS), and diminished glycogen synthesis in insulin-stimulated HepG2 cells, which was restored by exogenous expression of the βΔ-chain. By contrast, AAV8-mediated hepatic βΔ-chain overexpression significantly improved the insulin signaling pathway, thus activating glycogenesis and enhancing glycogen storage in the livers of high-fat diet(HFD)-fed mice.Conclusion: Our data revealed that LRP1, especially its β-chain, facilitates hepatic glycogenesis by improving the insulin signaling pathway, suggesting a new therapeutic strategy for hepatic insulin resistance-related diseases.
基金supported by the National Key Research and Development Plan(2022YFC3500202,China)the National Natural Science Foundation of China(Nos.82230116,81872877,82204715,81803142,82404639,and 82073975)+7 种基金the Natural Science Foundation of Jiangsu Province(No.BK20220476,China)the Jiangsu Provincial Double-Innovation Doctor Program(No.JSSCBS20220477,China)the Natural Science Foundation of Nanjing University of Chinese Medicine(No.XPT82204715,China)the Fundamental Research Funds for the Central Universities(Nos.020814380179 and 020814380174,China)the Fundamental Science(Natural Science)Research Project of the Jiangsu Higher Education Institutions of China(No.22KJB360005)the Innovation Project of Guangdong Provincial Education Department(No.2023KTSCX320,China)the Shenzhen Science and Technology Program(Nos.20231126130044001 and 20230731094501002,China)the School of Life Science(NJU)-Sipimo Joint Funds,and the Mountain-Climbing Talents Project of Nanjing.
文摘Psoriasis is an incurable chronic inflammatory disease that requires new interventions.Here,we found that fibroblasts exacerbate psoriasis progression by promoting macrophage recruitment via CCL2 secretion by single-cell multi-omics analysis.The natural small molecule celastrol was screened to interfere with the secretion of CCL2 by fibroblasts and improve the psoriasis-like symptoms in both murine and cynomolgus monkey models.Mechanistically,celastrol directly bound to the low-density lipoprotein receptor-related protein 1(LRP1)β-chain and abolished its binding to the transcription factor c-Jun in the nucleus,which in turn inhibited CCL2 production by skin fibroblasts,blocked fibroblast-macrophage crosstalk,and ameliorated psoriasis progression.Notably,fibroblast-specific LRP1 knockout mice exhibited a significant reduction in psoriasis like inflammation.Taken together,from clinical samples and combined with various mouse models,we revealed the pathogenesis of psoriasis from the perspective of fibroblast-macrophage crosstalk,and provided a foundation for LRP1 as a novel potential target for psoriasis treatment.
基金supported,in part,by National Natural Science Foundation of China(grant numbers 81673709,82004231,U1801284 and 81873209)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(grant number 2017BT01Y036,China)and GDUPS(2019,China)+5 种基金Guangdong Science and Technology Foundation for Distinguished Young Scholars(grant number 2017A030306004,China)Science and Technology Program of Guangzhou(grant numbers 201903010062 and 202102010116,China)Fellowship of China Postdoctoral Science Foundation(grant number 2020M683204,China)Guangdong Basic and Applied Basic Research Fund(grant number 2020A1515110388,China)Fundamental Research Funds for the Central Universities(grant number 21620448,China)support of K.C.Wong Education Foundation。
文摘The relationship between chronic psychological stress and tumorigenesis has been well defined in epidemiological studies;however, the underlying mechanism remains underexplored. In this study, we discovered that impaired macrophage phagocytosis contributed to the psychological stressevoked tumor susceptibility, and the stress hormone glucocorticoid(GC) was identified as a principal detrimental factor. Mechanistically, GC disturbed the balance of the "eat me" signal receptor(low-density lipoprotein receptor-related protein-1, LRP1) and the "don’t eat me" signal receptor(signal regulatory protein alpha, SIRPa). Further analysis revealed that GC led to a direct, glucocorticoid receptor(GR)-dependent trans-repression of LRP1 expression, and the repressed LRP1, in turn, resulted in the elevatedgene level of SIRPa by down-regulating mi RNA-4695-3 p. These data collectively demonstrate that stress induces the imbalance of the LRP1/SIRPa axis and entails the disturbance of tumor cell clearance by macrophages. Our findings provide the mechanistic insight into psychological stress-evoked tumor susceptibility and indicate that the balance of LRP1/SIRPa axis may serve as a potential therapeutic strategy for tumor treatment.
