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Background: Alzheimer's disease (AD) is the most prevalent type of dementia and represents 60-80% of dementia cases. AD affects over 32 million people globally, and 8.1% of affected females and 5.4% of affected males were older than 65 years. Cognitive rehabilitation focuses on helping patients develop individualized strategies to obtain or maintain optimal functioning. As of now, there is no complete and systematic meta-analysis on the effects of cognitive rehabilitation on cognitive functioning in AD patients. Objectives: To provide the most recent and extensive pooled analysis and evidence and explore the influence of cognitive rehabilitation on overall cognitive functioning in patients with AD. Methods: We searched articles through several databases such as PubMed, Cochrane Library, Embase, and Web of Science, from the inception to June 2023. Studies on cognitive stimulation, cognitive training, and cognitive interventions, and non-English articles were excluded. The outcome measures encompassed the effects of cognitive rehabilitation on the overall cognitive functioning of people with AD (e.g., verbal fluency, behavioral memory, neuropsychiatric status and occupational performance levels). Results: A total of 14 clinical trials were included in this analysis. The meta-analysis showed that cognitive rehabilitation significantly improved quality of life (WMD: 2.87; 95% CI: 0.79, 4.95; p = 0.007) and occupational performance levels (WMD: 1.53; 95% CI: 0.43, 2.63; p = 0.007) in patients with AD. However, it did not show a significant effect on other domains of specific cognitive functions in patients with AD. Conclusion: Cognitive rehabilitation exhibited a moderate to large impact on both quality of life and occupational performance levels in people with AD. Future studies are required to explore the potential of various cognitive interventions across specific domains, so as to provide more insights into the management of AD. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42023444390.
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White matter injury (WMI) causes oligodendrocyte precursor cell (OPC) differentiation arrest and functional deficits, with no effective therapies to date. Here, we report increased expression of growth hormone (GH) in the hypoxic neonatal mouse brain, a model of WMI. GH treatment during or post hypoxic exposure rescues hypoxia-induced hypomyelination and promotes functional recovery in adolescent mice. Single-cell sequencing reveals that Ghr mRNA expression is highly enriched in vascular cells. Cell-lineage labeling and tracing identify the GHR-expressing vascular cells as a subpopulation of pericytes. These cells display tip-cell-like morphology with kinetic polarized filopodia revealed by two-photon live imaging and seemingly direct blood vessel branching and bridging. Gain-of-function and loss-of-function experiments indicate that GHR signaling in pericytes is sufficient to modulate angiogenesis in neonatal brains, which enhances OPC differentiation and myelination indirectly. These findings demonstrate that targeting GHR and/or downstream effectors may represent a promising therapeutic strategy for WMI.
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Bainha de Mielina , Neovascularização Fisiológica , Pericitos , Animais , Pericitos/metabolismo , Pericitos/efeitos dos fármacos , Camundongos , Bainha de Mielina/metabolismo , Neovascularização Fisiológica/efeitos dos fármacos , Neovascularização Fisiológica/fisiologia , Hormônio do Crescimento/metabolismo , Hormônio do Crescimento/farmacologia , Animais Recém-Nascidos , Hipóxia/metabolismo , Diferenciação Celular/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Células Precursoras de Oligodendrócitos/metabolismo , Células Precursoras de Oligodendrócitos/efeitos dos fármacos , Receptores da Somatotropina/metabolismo , Receptores da Somatotropina/genética , AngiogêneseRESUMO
BACKGROUND: The effect of drug-drug interaction (DDI) between tacrolimus and voriconazole on the pharmacokinetics of tacrolimus in different CYP3A5 genotypes has not been reported in previous studies. OBJECTIVE: The objective of this study was to investigate whether CYP3A5 genotype could influence tacrolimus-voriconazole DDI in Chinese kidney transplant patients. METHODS: All kidney transplant patients were divided into combination and non-combination groups based on whether tacrolimus was combined with or without voriconazole. Each group was subdivided into CYP3A5 expresser (CYP3A5*1/*1 or CYP3A5*1/*3) and CYP3A5 nonexpresser (CYP3A5*3/*3). A retrospective analysis compared tacrolimus dose (D)-corrected trough concentrations (C0) (C0/D) between combination and non-combination groups, respectively. Tacrolimus C0/D was also compared between CYP3A5 expresser and nonexpresser in both groups. RESULTS: The C0/D values of tacrolimus were significantly different between CYP3A5 expresser and nonexpresser in combination group (378.20 [219.38, 633.48] ng/mL/[mg/kg/d] vs 720.00 [595.35, 1681.50] ng/mL/[mg/kg/d], P = 0.0010). Either in CYP3A5 expresser or nonexpresser, we found a statistically significant difference in tacrolimus C0/D between combination and non-combination group (P < 0.0001). The increase in CYP3A5 nonexpresser was 1.38 times higher than that in CYP3A5 expresser (320.93% vs 232.19%). CONCLUSION AND RELEVANCE: The median C0/D values were 90.38% higher in kidney transplant recipients with CYP3A5*3/*3 genotype than in those with CYP3A5*1/*1 or CYP3A5*1/*3 genotype when treated with both tacrolimus and voriconazole. A CYP3A5 genotype-dependent DDI was found between tacrolimus and voriconazole. Therefore, personalized therapy accounting for CYP3A5 genotype detection and therapeutic drug monitoring is necessary for kidney transplant patients when treating with tacrolimus and voriconazole.
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OBJECTIVE: To evaluate the relationship between GLP-1R gene polymorphisms and type 2 diabetes mellitus with dyslipidemia and without dyslipidemia in China. METHODS: A total of 200 patients with Type 2 Diabetes Mellitus (T2DM) were included in this study, including 115 with dyslipidemia and 85 without dyslipidemia. We used Sanger double deoxygenation terminal assay and PCR-RFLP to detect genotype of the GLP-1R rs10305420 and rs3765467 loci. T-test was used to analyze the association between gene polymorphisms and lipid indicators. SHEsis online analysis software was used to analyze the linkage balance effect of loci, and SPSS 26 was used to calculate the gene interaction by dominant model. RESULTS: The genotype distribution of the two loci in the sample of this study was in accordance with Hardy-weinberg equilibrium. There were significant differences in the genotype distribution and allele frequency of rs3765467 between T2DM patients with and without dyslipidemia (GG 52.9%, GA + AA 47.1% vs. GG 69.6%, GA + AA 30.4%; P = 0.017). Under the dominant model, the effects of rs3765467 A allele and rs10305420 T allele on dyslipidemia had multiplicative interactions (P = 0.016) and additive interactions (RERI = 0.403, 95% CI [-2.708 to 3.514]; AP = 0.376, 95% CI [-2.041, 2.793]). Meanwhile, HbA1c levels in rs3765467 A allele carriers (GA + AA) were found to be significantly lower than those in patients with GG genotype (P = 0.006). CONCLUSION: The rs3765467 (G/A) variant is associated with the incidence of dyslipidemia, and G allele may be a risk factor for dyslipidemia.
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Diabetes Mellitus Tipo 2 , Dislipidemias , Receptor do Peptídeo Semelhante ao Glucagon 1 , Humanos , Estudos de Casos e Controles , China/epidemiologia , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/epidemiologia , Dislipidemias/genética , População do Leste Asiático , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Polimorfismo de Nucleotídeo Único , Receptor do Peptídeo Semelhante ao Glucagon 1/genéticaRESUMO
Alzheimer's disease (AD) is characterized by aggregating amyloid beta-protein (Aß). Recent evidence has shown that insufficient myelinogenesis contributes to AD-related functional deficits. However, it remains unclear whether Aß, in either plaque or soluble form, could alter myelinogenesis in AD brains. By cell-lineage tracing and labeling, we found both myelinogenesis and Aß deposits displayed a region-specific pattern in the 13-month-old APP/PS1 transgenic mouse brains. Aß plaques cause focal demyelination, but only about 15% Aß plaques are closely associated with newly formed myelin in the APP/PS1 brains. Further, the Aß plaque total area and the amount of new myelin are not linearly correlated across different cortical regions, suggesting that Aß plaques induce demyelination but may not exclusively trigger remyelination. To understand the role of soluble Aß in regulating myelinogenesis, we chose to observe the visual system, wherein soluble Aß is detectable but without the presence of Aß plaques in the APP/PS1 retina, optic nerve, and optic tract. Interestingly, newly-formed myelin density was not significantly altered in the APP/PS1 optic nerves and optic tracts as compared to the wildtype controls, suggesting soluble Aß probably does not change myelinogenesis. Further, treatment of purified oligodendrocyte precursor cells (OPCs) with soluble Aß (oligomers) for 48 h did not change the cell densities of MBP positive cells and PDGFRα positive OPCs in vitro. Consistently, injection of soluble Aß into the lateral ventricles did not alter myelinogenesis in the corpus callosum of NG2-CreErt; Tau-mGFP mice significantly. Together, these findings indicate that the region-dependent myelinogenesis in AD brains is not directly linked to Aß, but rather probably a synergic result in adapting to AD pathology.
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Doença de Alzheimer , Doenças Desmielinizantes , Camundongos , Animais , Peptídeos beta-Amiloides/metabolismo , Camundongos Transgênicos , Precursor de Proteína beta-Amiloide/metabolismo , Presenilina-1 , Doença de Alzheimer/patologia , Encéfalo/metabolismo , Doenças Desmielinizantes/patologia , Modelos Animais de Doenças , Placa Amiloide/patologiaRESUMO
Exposure to chronic hypoxia is considered to be a risk factor for deficits in brain function in adults, but the underlying mechanisms remain largely unknown. Since active myelinogenesis persists in the adult central nervous system, here we aimed to investigate the impact of chronic hypoxia on myelination and the related functional consequences in adult mice. Using a transgenic approach to label newly-generated myelin sheaths (NG2-CreERTM; Tau-mGFP), we found that myelinogenesis was highly active in most brain regions, such as the motor cortex and corpus callosum. After exposure to hypoxia (10% oxygen) 12 h per day for 4 weeks, myelinogenesis was largely inhibited in the 4-month old brain and the mice displayed motor coordination deficits revealed by the beam-walking test. To determine the relationship between the inhibited myelination and functional impairment, we induced oligodendroglia-specific deletion of the transcription factor Olig2 by tamoxifen (NG2-CreERTM; Tau-mGFP; Olig2 fl/fl) in adult mice to mimic the decreased myelinogenesis caused by hypoxia. The deletion of Olig2 inhibited myelinogenesis and consequently impaired motor coordination, suggesting that myelinogenesis is required for motor function in adult mice. To understand whether enhancing myelination could protect brain functions against hypoxia, we treated hypoxic mice with the myelination-enhancing drug-clemastine, which resulted in enhanced myelogenesis and improved motor coordination. Taken together, our data indicate that chronic hypoxia inhibits myelinogenesis and causes functional deficits in the brain and that enhancing myelinogenesis protects brain functions against hypoxia-related deficits.
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Bainha de Mielina , Oligodendroglia , Animais , Clemastina , Hipóxia/complicações , Camundongos , Camundongos Endogâmicos C57BL , Camundongos TransgênicosRESUMO
Severe cognitive decline is a hallmark of Alzheimer's disease (AD). In addition to gray matter loss, significant white matter pathology has been identified in AD patients. Here, we characterized the dynamics of myelin generation and loss in the APP/PS1 mouse model of AD. Unexpectedly, we observed a dramatic increase in the rate of new myelin formation in APP/PS1 mice, reminiscent of the robust oligodendroglial response to demyelination. Despite this increase, overall levels of myelination are decreased in the cortex and hippocampus of APP/PS1 mice and postmortem AD tissue. Genetically or pharmacologically enhancing myelin renewal, by oligodendroglial deletion of the muscarinic M1 receptor or systemic administration of the pro-myelinating drug clemastine, improved the performance of APP/PS1 mice in memory-related tasks and increased hippocampal sharp wave ripples. Taken together, these results demonstrate the potential of enhancing myelination as a therapeutic strategy to alleviate AD-related cognitive impairment.
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Doença de Alzheimer/patologia , Disfunção Cognitiva/patologia , Aprendizagem em Labirinto/fisiologia , Bainha de Mielina/patologia , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Disfunção Cognitiva/genética , Disfunção Cognitiva/metabolismo , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , Bainha de Mielina/genética , Bainha de Mielina/metabolismo , Presenilina-1/genética , Presenilina-1/metabolismoRESUMO
Increasing evidence has shown that astrocytes are implicated in regulating oligodendrocyte myelination, but the underlying mechanisms remain largely unknown. To understand whether microRNAs in astrocytes function in regulating oligodendroglial differentiation and myelination in the developing and adult CNS, we generated inducible astrocyte-specific Dicer conditional knockout mice (hGFAP-CreERT; Dicer fl/fl). By using a reporter mouse line (mT/mG), we confirmed that hGFAP-CreERT drives an efficient and astrocyte-specific recombination in the developing CNS, upon tamoxifen treatment from postnatal day 3 (P3) to P7. The Dicer deletion in astrocytes resulted in inhibited oligodendroglial differentiation and myelination in the developing CNS of Dicer cKO mice at P10 and P14, and did not alter the densities of neurons or axons, indicating that Dicer in astrocytes is required for oligodendrocyte myelination. Consequently, the Dicer deletion in astrocytes at P3 resulted in impaired spatial memory and motor coordination at the age of 9 weeks. To understand whether Dicer in astrocytes is also required for remyelination, we induced Dicer deletion in 3-month-old mice and then injected lysolecithin into the corpus callosum to induce demyelination. The Dicer deletion in astrocytes blocked remyelination in the corpus callosum 14 days after induced demyelination. Together, our results indicate that Dicer in astrocytes is required for oligodendroglia myelination in both the developing and adult CNS.
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Diferenciação Celular , RNA Helicases DEAD-box/genética , Bainha de Mielina , Oligodendroglia/citologia , Remielinização , Ribonuclease III/genética , Animais , Astrócitos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NeurogêneseRESUMO
Rationale: There is a continued need for investigating the roles of microRNAs and their targets on the pathogenesis of pulmonary arterial hypertension (PAH) vascular remodeling. We recently identified the association of myeloid miR-182-3p and its new target, Myeloid-Associated Differentiation Marker (Myadm), with vascular remodeling. Here, we aimed to determine the role of miR-182-3p/Myadm on PAH vascular remodeling and the underlying molecular mechanism. Methods: The miR-182-3p/Myadm expression profiles were detected in PAH patients and experimental rodent models. Loss-of-function and gain-of-function studies using gene knock-in or gene knock-out and the combinations of the proteomic technology and genome-wide ChIP-Seq were employed to determine the downstream targets of miR-182-3p/Myadm in response to monocrotaline (MCT)-induced PAH. Results: The miR-182-3p/Myadm expression was altered in PAH patients and experimental rodent models. Both miR-182-3p inhibitor and overexpression of Myadm augmented the pathological progression in rats in response to MCT-induced PAH. In contrast, miR-182-3p mimic and Myadm gene knockout attenuated the changes in the hemodynamics and structure of the cardio-pulmonary system in MCT-induced PAH in rats. Myadm mediated the proliferation of pulmonary artery smooth muscle cells (PASMCs) by altering the cell cycle kinase inhibitor (p21/Cip1) expression through the transcription factor Krüppel-like factor 4 (KLF4) translocation into the cytoplasm. Conclusion: Our findings indicate the prognostic and therapeutic significance of miR-182-3p in PAH and provide a new regulatory model of the myeloid-derived miR-182-3p/Myadm/KLF4/p21 axis in PAH vascular remodeling.
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Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Fatores de Transcrição Kruppel-Like/metabolismo , MicroRNAs/genética , Proteínas Proteolipídicas Associadas a Linfócitos e Mielina/metabolismo , Hipertensão Arterial Pulmonar/patologia , Remodelação Vascular , Animais , Estudos de Casos e Controles , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/genética , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica , Técnicas de Inativação de Genes , Humanos , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/genética , Masculino , Proteínas Proteolipídicas Associadas a Linfócitos e Mielina/genética , Miócitos de Músculo Liso/metabolismo , Hipertensão Arterial Pulmonar/genética , Hipertensão Arterial Pulmonar/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de SinaisRESUMO
Cognitive decline remains an unaddressed problem for the elderly. We show that myelination is highly active in young mice and greatly inhibited in aged mice, coinciding with spatial memory deficits. Inhibiting myelination by deletion of Olig2 in oligodendrocyte precursor cells impairs spatial memory in young mice, while enhancing myelination by deleting the muscarinic acetylcholine receptor 1 in oligodendrocyte precursor cells, or promoting oligodendroglial differentiation and myelination via clemastine treatment, rescues spatial memory decline during aging.
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Envelhecimento/patologia , Doenças Desmielinizantes/patologia , Transtornos da Memória/patologia , Bainha de Mielina/patologia , Envelhecimento/genética , Animais , Doenças Desmielinizantes/complicações , Doenças Desmielinizantes/genética , Doenças Desmielinizantes/metabolismo , Transtornos da Memória/etiologia , Transtornos da Memória/genética , Transtornos da Memória/metabolismo , Camundongos , Camundongos Transgênicos , Proteína Básica da Mielina/genética , Proteína Básica da Mielina/metabolismo , Bainha de Mielina/metabolismo , Células Precursoras de Oligodendrócitos/metabolismo , Células Precursoras de Oligodendrócitos/patologia , Fator de Transcrição 2 de Oligodendrócitos/genética , Fator de Transcrição 2 de Oligodendrócitos/metabolismo , Oligodendroglia/metabolismo , Oligodendroglia/patologiaRESUMO
DNA methylation has been implicated in the pathogenesis of diabetic kidney disease (DKD), but the underlying mechanisms remain unclear. In this study, we tested the hypothesis that aberrant DNA methylation in peripheral immune cells contributes to DKD progression. We showed that levels of DNA methyltransferase 1 (DNMT1), a key enzyme for DNA methylation, were increased along with inflammatory activity of peripheral blood mononuclear cells in DKD patients. Inhibition of DNMT1 with 5-aza-2'-deoxycytidine (5-Aza) markedly increased the proportion of CD4+CD25+ regulatory T cells in peripheral blood mononuclear cells in culture and in diabetic animals. Adoptive transfer of immune cells from 5-Aza-treated animals showed beneficial effects on the host immune system, resulting in a significant improvement of DKD. Using genome-wide DNA methylation assays, we identified the differentially methylated cytosines in the promoter regions of mammalian target of rapamycin (mTOR) regulators in peripheral blood mononuclear cells of diabetic patients. Further, mRNA arrays confirmed the consistent induction of genes expressed in the mTOR pathway. Importantly, down-regulation of DNMT1 expression via RNA interference resulted in prominent cytosine demethylation of mTOR negative regulators and subsequent decrease of mTOR activity. Lastly, modulation of mTOR resulted in changes in the effect of 5-aza on diabetic immune cells. Thus, up-regulation of DNMT1 in diabetic immune cells induces aberrant cytosine methylation of the upstream regulators of mTOR, leading to pathogenic activation of the mTOR pathway and consequent inflammation in diabetic kidneys. Hence, this study highlights therapeutic potential of targeting epigenetic events in immune system for treating DKD.
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DNA (Citosina-5-)-Metiltransferase 1/sangue , Metilação de DNA/imunologia , Nefropatias Diabéticas/imunologia , Leucócitos Mononucleares/imunologia , Transdução de Sinais/genética , Adolescente , Transferência Adotiva , Adulto , Idoso , Animais , Azacitidina/administração & dosagem , Citosina/metabolismo , DNA (Citosina-5-)-Metiltransferase 1/antagonistas & inibidores , DNA (Citosina-5-)-Metiltransferase 1/genética , Nefropatias Diabéticas/sangue , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/terapia , Modelos Animais de Doenças , Progressão da Doença , Epigênese Genética/efeitos dos fármacos , Epigênese Genética/imunologia , Feminino , Técnicas de Silenciamento de Genes , Humanos , Leucócitos Mononucleares/metabolismo , Masculino , Camundongos , Pessoa de Meia-Idade , Cultura Primária de Células , Regiões Promotoras Genéticas/genética , Transdução de Sinais/imunologia , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Regulação para Cima/genética , Regulação para Cima/imunologia , Adulto JovemRESUMO
Loss of the microvascular (MV) network results in tissue ischemia, loss of tissue function, and is a hallmark of chronic diseases. The incorporation of a functional vascular network with that of the host remains a challenge to utilizing engineered tissues in clinically relevant therapies. We showed that vascular-bed-specific endothelial cells (ECs) exhibit differing angiogenic capacities, with kidney microvascular endothelial cells (MVECs) being the most deficient, and sought to explore the underlying mechanism. Constitutive activation of the phosphatase PTEN in kidney MVECs resulted in impaired PI3K/AKT activity in response to vascular endothelial growth factor (VEGF). Suppression of PTEN in vivo resulted in microvascular regeneration, but was insufficient to improve tissue function. Promoter analysis of the differentially regulated genes in KMVECs suggests that the transcription factor FOXO1 is highly active and RNAseq analysis revealed that hyperactive FOXO1 inhibits VEGF-Notch-dependent tip-cell formation by direct and indirect inhibition of DLL4 expression in response to VEGF. Inhibition of FOXO1 enhanced angiogenesis in human bio-engineered capillaries, and resulted in microvascular regeneration and improved function in mouse models of injury-repair.
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Proteína Forkhead Box O1/metabolismo , Rim/irrigação sanguínea , Rim/fisiopatologia , Microvasos/fisiopatologia , Neovascularização Fisiológica , Adulto , Animais , Células Cultivadas , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Humanos , Rim/lesões , Rim/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microvasos/metabolismo , Microvasos/fisiologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
Connective tissue growth factor (CTGF), a matrix-associated protein with four distinct cytokine binding domains, has roles in vasculogenesis, wound healing responses, and fibrogenesis and is upregulated in fibroblasts and myofibroblasts in disease. Here, we investigated the role of CTGF in fibrogenic cells. In mice, tissue-specific inducible overexpression of CTGF by kidney pericytes and fibroblasts had no bearing on nephrogenesis or kidney homeostasis but exacerbated inflammation and fibrosis after ureteral obstruction. These effects required the WNT receptor LDL receptor-related protein 6 (LRP6). Additionally, pericytes isolated from these mice became hypermigratory and hyperproliferative on overexpression of CTGF. CTGF is cleaved in vivo into distinct domains. Treatment with recombinant domain 1, 1+2 (N terminus), or 4 (C terminus) independently activated myofibroblast differentiation and wound healing responses in cultured pericytes, but domain 4 showed the broadest profibrotic activity. Domain 4 exhibited low-affinity binding to LRP6 in in vitro binding assays, and inhibition of LRP6 or critical signaling cascades downstream of LRP6, including JNK and WNT/ß-catenin, inhibited the biologic activity of domain 4. Administration of blocking antibodies specifically against CTGF domain 4 or recombinant Dickkopf-related protein-1, an endogenous inhibitor of LRP6, effectively inhibited inflammation and fibrosis associated with ureteral obstruction in vivo Therefore, domain 4 of CTGF and the WNT signaling pathway are important new targets in fibrosis.
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Fator de Crescimento do Tecido Conjuntivo/fisiologia , Nefropatias/etiologia , Rim/patologia , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/fisiologia , Animais , Fator de Crescimento do Tecido Conjuntivo/antagonistas & inibidores , Fibroblastos , Fibrose/etiologia , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , PericitosRESUMO
Human kidney peritubular capillaries are particularly susceptible to injury, resulting in dysregulated angiogenesis, capillary rarefaction and regression, and progressive loss of kidney function. However, little is known about the structure and function of human kidney microvasculature. Here, we isolated, purified, and characterized human kidney peritubular microvascular endothelial cells (HKMECs) and reconstituted a three-dimensional human kidney microvasculature in a flow-directed microphysiologic system. By combining epithelial cell depletion and cell culture in media with high concentrations of vascular endothelial growth factor, we obtained HKMECs of high purity in large quantity. Unlike other endothelial cells, isolated HKMECs depended on high vascular endothelial growth factor concentration for survival and growth and exhibited high tubulogenic but low angiogenic potential. Furthermore, HKMECs had a different transcriptional profile. Under flow, HKMECs formed a thin fenestrated endothelium with a functional permeability barrier. In conclusion, this three-dimensional HKMEC-specific microphysiologic system recapitulates human kidney microvascular structure and function and shows phenotypic characteristics different from those of other microvascular endothelial cells.
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Capilares/citologia , Células Endoteliais , Túbulos Renais/citologia , Células Cultivadas , Progressão da Doença , Humanos , Nefropatias/etiologiaRESUMO
MicroRNAs, activated by the enzyme Dicer1, control post-transcriptional gene expression. Dicer1 has important roles in the epithelium during nephrogenesis, but its function in stromal cells during kidney development is unknown. To study this, we inactivated Dicer1 in renal stromal cells. This resulted in hypoplastic kidneys, abnormal differentiation of the nephron tubule and vasculature, and perinatal mortality. In mutant kidneys, genes involved in stromal cell migration and activation were suppressed as were those involved in epithelial and endothelial differentiation and maturation. Consistently, polarity of the proximal tubule was incorrect, distal tubule differentiation was diminished, and elongation of Henle's loop attenuated resulting in lack of inner medulla and papilla in stroma-specific Dicer1 mutants. Glomerular maturation and capillary loop formation were abnormal, whereas peritubular capillaries, with enhanced branching and increased diameter, formed later. In Dicer1-null renal stromal cells, expression of factors associated with migration, proliferation, and morphogenic functions including α-smooth muscle actin, integrin-α8, -ß1, and the WNT pathway transcriptional regulator LEF1 were reduced. Dicer1 mutation in stroma led to loss of expression of distinct microRNAs. Of these, miR-214, -199a-5p, and -199a-3p regulate stromal cell functions ex vivo, including WNT pathway activation, migration, and proliferation. Thus, Dicer1 activity in the renal stromal compartment regulates critical stromal cell functions that, in turn, regulate differentiation of the nephron and vasculature during nephrogenesis.
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Diferenciação Celular/genética , RNA Helicases DEAD-box/fisiologia , Neovascularização Fisiológica/genética , Néfrons/embriologia , Ribonuclease III/fisiologia , Actinas/metabolismo , Animais , Capilares/embriologia , Movimento Celular/genética , Proliferação de Células/genética , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Feminino , Expressão Gênica , Cadeias alfa de Integrinas/metabolismo , Glomérulos Renais/irrigação sanguínea , Glomérulos Renais/citologia , Glomérulos Renais/embriologia , Túbulos Renais/irrigação sanguínea , Túbulos Renais/citologia , Túbulos Renais/embriologia , Túbulos Renais Distais/irrigação sanguínea , Túbulos Renais Distais/citologia , Túbulos Renais Distais/embriologia , Túbulos Renais Proximais/irrigação sanguínea , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/embriologia , Alça do Néfron/irrigação sanguínea , Alça do Néfron/citologia , Alça do Néfron/embriologia , Camundongos , MicroRNAs/genética , Néfrons/anormalidades , Néfrons/citologia , Organogênese/genética , Podócitos/fisiologia , Ribonuclease III/genética , Ribonuclease III/metabolismo , Células Estromais/fisiologia , Transcriptoma , Ureter/anormalidades , Via de Sinalização Wnt/genéticaRESUMO
MicroRNA-21 (miR-21) contributes to the pathogenesis of fibrogenic diseases in multiple organs, including the kidneys, potentially by silencing metabolic pathways that are critical for cellular ATP generation, ROS production, and inflammatory signaling. Here, we developed highly specific oligonucleotides that distribute to the kidney and inhibit miR-21 function when administered subcutaneously and evaluated the therapeutic potential of these anti-miR-21 oligonucleotides in chronic kidney disease. In a murine model of Alport nephropathy, miR-21 silencing did not produce any adverse effects and resulted in substantially milder kidney disease, with minimal albuminuria and dysfunction, compared with vehicle-treated mice. miR-21 silencing dramatically improved survival of Alport mice and reduced histological end points, including glomerulosclerosis, interstitial fibrosis, tubular injury, and inflammation. Anti-miR-21 enhanced PPARα/retinoid X receptor (PPARα/RXR) activity and downstream signaling pathways in glomerular, tubular, and interstitial cells. Moreover, miR-21 silencing enhanced mitochondrial function, which reduced mitochondrial ROS production and thus preserved tubular functions. Inhibition of miR-21 was protective against TGF-ß-induced fibrogenesis and inflammation in glomerular and interstitial cells, likely as the result of enhanced PPARα/RXR activity and improved mitochondrial function. Together, these results demonstrate that inhibition of miR-21 represents a potential therapeutic strategy for chronic kidney diseases including Alport nephropathy.
Assuntos
MicroRNAs/genética , Nefrite Hereditária/terapia , Oligorribonucleotídeos Antissenso/genética , Animais , Autoantígenos/genética , Colágeno Tipo IV/deficiência , Colágeno Tipo IV/genética , Progressão da Doença , Fibrose/metabolismo , Rim/metabolismo , Rim/patologia , Redes e Vias Metabólicas/genética , Camundongos da Linhagem 129 , MicroRNAs/metabolismo , Nefrite Hereditária/metabolismo , Nefrite Hereditária/patologia , Espécies Reativas de Oxigênio/metabolismo , Transcriptoma , Regulação para CimaRESUMO
FSGS is a heterogeneous fibrosing disease of the kidney, the cause of which remains poorly understood. In most cases, there is no effective treatment to halt or retard progression to renal failure. Increasing evidence points to mitochondrial dysfunction and the generation of reactive oxygen species in the pathogenesis of CKD. Autophagy, a major intracellular lysosomal degradation system, performs homeostatic functions linked to metabolism and organelle turnover. We prevented normal autophagic pathways in nephrons of mice by mutating critical autophagy genes ATG5 or ATG7 during nephrogenesis. Mutant mice developed mild podocyte and tubular dysfunction within 2 months, profound glomerular and tubular changes bearing close similarity to human disease by 4 months, and organ failure by 6 months. Ultrastructurally, podocytes and tubular cells showed vacuolization, abnormal mitochondria, and evidence of endoplasmic reticulum stress, features that precede the appearance of histologic or clinical disease. Similar changes were observed in human idiopathic FSGS kidney biopsy specimens. Biochemical analysis of podocytes and tubules of 2-month-old mutant mice revealed elevated production of reactive oxygen species, activation of endoplasmic reticulum stress pathways, phosphorylation of p38, and mitochondrial dysfunction. Furthermore, cultured proximal tubule cells isolated from mutant mice showed marked mitochondrial dysfunction and elevated mitochondrial reactive oxygen species generation that was suppressed by a mitochondrial superoxide scavenger. We conclude that mitochondrial dysfunction and endoplasmic reticulum stress due to impaired autophagic organelle turnover in podocytes and tubular epithelium are sufficient to cause many of the manifestations of FSGS in mice.
Assuntos
Glomerulosclerose Segmentar e Focal/etiologia , Proteínas Associadas aos Microtúbulos/deficiência , Mitocôndrias/fisiologia , Podócitos/fisiologia , Animais , Autofagia , Proteína 5 Relacionada à Autofagia , Proteína 7 Relacionada à Autofagia , Modelos Animais de Doenças , Estresse do Retículo Endoplasmático , Glomerulosclerose Segmentar e Focal/metabolismo , Glomerulosclerose Segmentar e Focal/patologia , Humanos , Camundongos , Proteínas Associadas aos Microtúbulos/genética , Mitocôndrias/ultraestrutura , Mutação , Espécies Reativas de Oxigênio/metabolismo , Estudos Retrospectivos , Urotélio/metabolismoRESUMO
Therapy to slow the relentless expansion of interstitial extracellular matrix that leads to renal functional decline in patients with CKD is currently lacking. Because chronic kidney injury increases tissue oxidative stress, we evaluated the antifibrotic efficacy of cysteamine bitartrate, an antioxidant therapy for patients with nephropathic cystinosis, in a mouse model of unilateral ureteral obstruction. Fresh cysteamine (600 mg/kg) was added to drinking water daily beginning on the day of surgery, and outcomes were assessed on days 7, 14, and 21 after surgery. Plasma cysteamine levels showed diurnal variation, with peak levels similar to those observed in patients with cystinosis. In cysteamine-treated mice, fibrosis severity decreased significantly at 14 and 21 days after unilateral ureteral obstruction, and renal oxidized protein levels decreased at each time point, suggesting reduced oxidative stress. Consistent with these results, treatment of cultured macrophages with cysteamine reduced cellular generation of reactive oxygen species. Furthermore, treatment with cysteamine reduced α-smooth muscle actin-positive interstitial myofibroblast proliferation and mRNA levels of extracellular matrix proteins in mice and attenuated myofibroblast differentiation and proliferation in vitro, but did not augment TGF-ß signaling. In a study of renal ischemia reperfusion, cysteamine therapy initiated 10 days after injury and continued for 14 days decreased renal fibrosis by 40%. Taken together, these data suggest previously unrecognized antifibrotic actions of cysteamine via TGF-ß-independent mechanisms that include oxidative stress reduction and attenuation of the myofibroblast response to kidney injury and support further investigation into the potential benefit of cysteamine therapy in the treatment of CKD.
Assuntos
Antioxidantes/uso terapêutico , Cisteamina/uso terapêutico , Miofibroblastos/efeitos dos fármacos , Insuficiência Renal Crônica/tratamento farmacológico , Actinas/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Proteínas da Matriz Extracelular/genética , Fibrose , Proteínas de Ligação ao GTP/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miofibroblastos/metabolismo , Miofibroblastos/patologia , Estresse Oxidativo/efeitos dos fármacos , Proteína 2 Glutamina gama-Glutamiltransferase , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Insuficiência Renal Crônica/metabolismo , Insuficiência Renal Crônica/patologia , Transglutaminases/metabolismo , Obstrução Ureteral/tratamento farmacológico , Obstrução Ureteral/metabolismo , Obstrução Ureteral/patologiaRESUMO
The influence of nutritional and physical stress on sporulation, conidial germination and vegetative biomass of Ophiocordyceps sinensis, one of the most important medicinal fungi in China and now globally, was evaluated using a two-stage culture method. All the treatments, except nutrient deprivation, enhanced conidial production and vegetative biomass to some extent. However, conidia produced under stress showed decreased germination in comparison with those continuously cultured on the enriched potato dextrose agar (PDA; as the control). Among 10 treatments tested, the physical stress of frozen-shock produced the largest number of conidia, 7.5 times higher than that of the control, followed by heat-shock treatment. These results demonstrate that the fungus has strong physiological adaptations to environmental stress that may have evolved because it is endemic to the Tibetan Plateau. This report will be relevant to the study of the pathogenicity and artificial cultivation of this endangered fungus.
Assuntos
Hypocreales/fisiologia , Esporos Fúngicos/crescimento & desenvolvimento , Estresse Fisiológico , Biomassa , China , Temperatura Baixa , Meios de Cultura/química , Congelamento , Temperatura Alta , Hypocreales/crescimento & desenvolvimento , Hypocreales/metabolismo , Hypocreales/efeitos da radiaçãoRESUMO
PURPOSE OF REVIEW: Pericytes and perivascular fibroblasts have emerged as poorly appreciated yet extensive populations of mesenchymal cells in the kidney that play important roles in homeostasis and responses to injury. This review will update readers on the evolving understanding of the biology of these cells. RECENT FINDINGS: Fate mapping has identified pericytes and perivascular fibroblasts as the major source of pathological fibrillar matrix-forming cells in interstitial kidney disease. In other organs similar cells have been described and independent fate mapping indicates that pericytes or perivascular cells are myofibroblast progenitors in multiple organs. Over the last year, new insights into the function of pericytes in kidney homeostasis has been uncovered and new molecular pathways that regulate detachment and their transdifferentiation into pathological myofibroblasts, including Wingless/Int, ephrin, transforming growth factor ß, platelet derived growth factor, and Hedgehog signaling pathways, have been reported. In addition provocative studies indicate that microRNAs, which regulate posttranscriptional gene expression, may also play important roles in their transdifferentiation. SUMMARY: Pericytes and perivascular fibroblasts are the major source of pathological collagen fiber-forming cells in interstitial kidney diseases. New avenues of research into their activation and differentiation has identified new drug candidates for the treatment of interstitial kidney disease.