RESUMO
The immune system and the kidneys are closely related. Immune components mediate acute kidney disease and are crucial to the progression of chronic kidney disease. Beyond its pathogenic functions, the immune system supports immunological homeostasis in healthy kidneys. The kidneys help maintain immune equilibrium by removing metabolic waste products and toxins, thereby limiting local and systemic inflammation. In this review, we describe the close relationship between the immune system and the kidneys. We discuss how the imbalance in the immune response can be deleterious to the kidneys and how immunomodulation can be important in preventing end-stage renal disease. In addition, recent tools such as in silico platforms and kidney organoids can help unveil the relationship between immune cells and kidney homeostasis.
Assuntos
Nefropatias , Humanos , Animais , Nefropatias/imunologia , Nefropatias/etiologia , Nefropatias/metabolismo , Rim/imunologia , Rim/metabolismo , Homeostase , Imunomodulação , Suscetibilidade a DoençasRESUMO
The low-density lipoprotein (LDL) receptor-related protein 2 (LRP2 or megalin) is representative of the phylogenetically conserved subfamily of giant LDL receptor-related proteins, which function in endocytosis and are implicated in diseases of the kidney and brain. Here, we report high-resolution cryoelectron microscopy structures of LRP2 isolated from mouse kidney, at extracellular and endosomal pH. The structures reveal LRP2 to be a molecular machine that adopts a conformation for ligand binding at the cell surface and for ligand shedding in the endosome. LRP2 forms a homodimer, the conformational transformation of which is governed by pH-sensitive sites at both homodimer and intra-protomer interfaces. A subset of LRP2 deleterious missense variants in humans appears to impair homodimer assembly. These observations lay the foundation for further understanding the function and mechanism of LDL receptors and implicate homodimerization as a conserved feature of the LRP receptor subfamily.
Assuntos
Endocitose , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Animais , Humanos , Camundongos , Microscopia Crioeletrônica , Rim/metabolismo , Ligantes , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismoRESUMO
Clear cell renal carcinoma (ccRCC) is a heterogeneous disease with a variable post-surgical course. To assemble a comprehensive ccRCC tumor microenvironment (TME) atlas, we performed single-cell RNA sequencing (scRNA-seq) of hematopoietic and non-hematopoietic subpopulations from tumor and tumor-adjacent tissue of treatment-naive ccRCC resections. We leveraged the VIPER algorithm to quantitate single-cell protein activity and validated this approach by comparison to flow cytometry. The analysis identified key TME subpopulations, as well as their master regulators and candidate cell-cell interactions, revealing clinically relevant populations, undetectable by gene-expression analysis. Specifically, we uncovered a tumor-specific macrophage subpopulation characterized by upregulation of TREM2/APOE/C1Q, validated by spatially resolved, quantitative multispectral immunofluorescence. In a large clinical validation cohort, these markers were significantly enriched in tumors from patients who recurred following surgery. The study thus identifies TREM2/APOE/C1Q-positive macrophage infiltration as a potential prognostic biomarker for ccRCC recurrence, as well as a candidate therapeutic target.
Assuntos
Carcinoma de Células Renais/metabolismo , Recidiva Local de Neoplasia/genética , Macrófagos Associados a Tumor/metabolismo , Adulto , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Biomarcadores Tumorais/genética , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/patologia , Estudos de Coortes , Feminino , Expressão Gênica/genética , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Rim/metabolismo , Neoplasias Renais/patologia , Linfócitos do Interstício Tumoral/patologia , Macrófagos/metabolismo , Masculino , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/metabolismo , Prognóstico , Receptores de Complemento/genética , Receptores de Complemento/metabolismo , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Análise de Sequência de RNA/métodos , Análise de Célula Única/métodos , Microambiente Tumoral , Macrófagos Associados a Tumor/fisiologiaRESUMO
Erythropoietin (EPO) production in the kidney is regulated by the oxygen-sensing transcription factor HIF-1α, which is degraded under normoxic conditions by HIF-prolyl hydroxylase (HIF-PHD). Inhibition of HIF-PHD by roxadustat leads to increased EPO production, better iron absorption, and amelioration of anemia in chronic kidney disease (CKD).
Assuntos
Anemia/terapia , Glicina/análogos & derivados , Fator 1 Induzível por Hipóxia/metabolismo , Isoquinolinas/uso terapêutico , Anemia/metabolismo , Glicina/uso terapêutico , Humanos , Fator 1 Induzível por Hipóxia/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Prolil Hidroxilases/efeitos dos fármacos , Prolil Hidroxilases/metabolismo , Insuficiência Renal Crônica/tratamento farmacológico , Insuficiência Renal Crônica/metabolismoRESUMO
We show that SARS-CoV-2 spike protein interacts with both cellular heparan sulfate and angiotensin-converting enzyme 2 (ACE2) through its receptor-binding domain (RBD). Docking studies suggest a heparin/heparan sulfate-binding site adjacent to the ACE2-binding site. Both ACE2 and heparin can bind independently to spike protein in vitro, and a ternary complex can be generated using heparin as a scaffold. Electron micrographs of spike protein suggests that heparin enhances the open conformation of the RBD that binds ACE2. On cells, spike protein binding depends on both heparan sulfate and ACE2. Unfractionated heparin, non-anticoagulant heparin, heparin lyases, and lung heparan sulfate potently block spike protein binding and/or infection by pseudotyped virus and authentic SARS-CoV-2 virus. We suggest a model in which viral attachment and infection involves heparan sulfate-dependent enhancement of binding to ACE2. Manipulation of heparan sulfate or inhibition of viral adhesion by exogenous heparin presents new therapeutic opportunities.
Assuntos
Betacoronavirus/fisiologia , Heparitina Sulfato/metabolismo , Peptidil Dipeptidase A/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Sequência de Aminoácidos , Enzima de Conversão de Angiotensina 2 , Betacoronavirus/isolamento & purificação , Sítios de Ligação , COVID-19 , Linhagem Celular , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Heparina/química , Heparina/metabolismo , Heparitina Sulfato/química , Humanos , Rim/metabolismo , Pulmão/metabolismo , Simulação de Dinâmica Molecular , Pandemias , Peptidil Dipeptidase A/química , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Ligação Proteica , Domínios Proteicos , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Internalização do VírusRESUMO
Inflammation is an important component of fibrosis but immune processes that orchestrate kidney fibrosis are not well understood. Here we apply single-cell sequencing to a mouse model of kidney fibrosis. We identify a subset of kidney tubule cells with a profibrotic-inflammatory phenotype characterized by the expression of cytokines and chemokines associated with immune cell recruitment. Receptor-ligand interaction analysis and experimental validation indicate that CXCL1 secreted by profibrotic tubules recruits CXCR2+ basophils. In mice, these basophils are an important source of interleukin-6 and recruitment of the TH17 subset of helper T cells. Genetic deletion or antibody-based depletion of basophils results in reduced renal fibrosis. Human kidney single-cell, bulk gene expression and immunostaining validate a function for basophils in patients with kidney fibrosis. Collectively, these studies identify basophils as contributors to the development of renal fibrosis and suggest that targeting these cells might be a useful clinical strategy to manage chronic kidney disease.
Assuntos
Basófilos , Insuficiência Renal Crônica , Animais , Fibrose , Humanos , Rim/metabolismo , Túbulos Renais , Camundongos , Insuficiência Renal Crônica/metabolismo , Análise de Célula ÚnicaRESUMO
Intracellular accumulation of misfolded proteins causes toxic proteinopathies, diseases without targeted therapies. Mucin 1 kidney disease (MKD) results from a frameshift mutation in the MUC1 gene (MUC1-fs). Here, we show that MKD is a toxic proteinopathy. Intracellular MUC1-fs accumulation activated the ATF6 unfolded protein response (UPR) branch. We identified BRD4780, a small molecule that clears MUC1-fs from patient cells, from kidneys of knockin mice and from patient kidney organoids. MUC1-fs is trapped in TMED9 cargo receptor-containing vesicles of the early secretory pathway. BRD4780 binds TMED9, releases MUC1-fs, and re-routes it for lysosomal degradation, an effect phenocopied by TMED9 deletion. Our findings reveal BRD4780 as a promising lead for the treatment of MKD and other toxic proteinopathies. Generally, we elucidate a novel mechanism for the entrapment of misfolded proteins by cargo receptors and a strategy for their release and anterograde trafficking to the lysosome.
Assuntos
Benzamidas/metabolismo , Compostos Bicíclicos com Pontes/farmacologia , Heptanos/farmacologia , Lisossomos/efeitos dos fármacos , Proteínas de Transporte Vesicular/metabolismo , Fator 6 Ativador da Transcrição/metabolismo , Animais , Benzamidas/química , Benzamidas/farmacologia , Compostos Bicíclicos com Pontes/uso terapêutico , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Feminino , Mutação da Fase de Leitura , Heptanos/uso terapêutico , Humanos , Receptores de Imidazolinas/antagonistas & inibidores , Receptores de Imidazolinas/genética , Receptores de Imidazolinas/metabolismo , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/metabolismo , Rim/citologia , Rim/metabolismo , Rim/patologia , Nefropatias/metabolismo , Nefropatias/patologia , Lisossomos/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Mucina-1/química , Mucina-1/genética , Mucina-1/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Proteínas de Transporte Vesicular/químicaRESUMO
Group 3 innate lymphoid cells (ILC3s) regulate inflammation and tissue repair at mucosal sites, but whether these functions pertain to other tissues-like the kidneys-remains unclear. Here, we observed that renal fibrosis in humans was associated with increased ILC3s in the kidneys and blood. In mice, we showed that CXCR6+ ILC3s rapidly migrated from the intestinal mucosa and accumulated in the kidney via CXCL16 released from the injured tubules. Within the fibrotic kidney, ILC3s increased the expression of programmed cell death-1 (PD-1) and subsequent IL-17A production to directly activate myofibroblasts and fibrotic niche formation. ILC3 expression of PD-1 inhibited IL-23R endocytosis and consequently amplified the JAK2/STAT3/RORγt/IL-17A pathway that was essential for the pro-fibrogenic effect of ILC3s. Thus, we reveal a hitherto unrecognized migration pathway of ILC3s from the intestine to the kidney and the PD-1-dependent function of ILC3s in promoting renal fibrosis.
Assuntos
Movimento Celular , Fibrose , Rim , Linfócitos , Receptor de Morte Celular Programada 1 , Receptores CXCR6 , Receptores de Interleucina , Transdução de Sinais , Animais , Fibrose/imunologia , Camundongos , Receptores CXCR6/metabolismo , Receptores CXCR6/imunologia , Receptor de Morte Celular Programada 1/metabolismo , Transdução de Sinais/imunologia , Movimento Celular/imunologia , Humanos , Rim/patologia , Rim/imunologia , Rim/metabolismo , Linfócitos/imunologia , Linfócitos/metabolismo , Receptores de Interleucina/metabolismo , Receptores de Interleucina/imunologia , Camundongos Endogâmicos C57BL , Nefropatias/imunologia , Nefropatias/metabolismo , Nefropatias/patologia , Imunidade Inata/imunologia , Camundongos Knockout , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Intestinos/imunologia , Intestinos/patologiaRESUMO
The occurrence of a spontaneous nephropathy with intranuclear inclusions in laboratory mice has puzzled pathologists for over 4 decades, because its etiology remains elusive. The condition is more severe in immunodeficient animals, suggesting an infectious cause. Using metagenomics, we identify the causative agent as an atypical virus, termed "mouse kidney parvovirus" (MKPV), belonging to a divergent genus of Parvoviridae. MKPV was identified in animal facilities in Australia and North America, is transmitted via a fecal-oral or urinary-oral route, and is controlled by the adaptive immune system. Detailed analysis of the clinical course and histopathological features demonstrated a stepwise progression of pathology ranging from sporadic tubular inclusions to tubular degeneration and interstitial fibrosis and culminating in renal failure. In summary, we identify a widely distributed pathogen in laboratory mice and establish MKPV-induced nephropathy as a new tool for elucidating mechanisms of tubulointerstitial fibrosis that shares molecular features with chronic kidney disease in humans.
Assuntos
Nefrite Intersticial/virologia , Parvovirus/isolamento & purificação , Parvovirus/patogenicidade , Animais , Austrália , Progressão da Doença , Feminino , Fibrose/patologia , Fibrose/virologia , Humanos , Rim/metabolismo , Rim/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Nefrite Intersticial/fisiopatologia , América do Norte , Infecções por Parvoviridae/metabolismoRESUMO
Hibernating mammals survive hypothermia (<10°C) without injury, a remarkable feat of cellular preservation that bears significance for potential medical applications. However, mechanisms imparting cold resistance, such as cytoskeleton stability, remain elusive. Using the first iPSC line from a hibernating mammal (13-lined ground squirrel), we uncovered cellular pathways critical for cold tolerance. Comparison between human and ground squirrel iPSC-derived neurons revealed differential mitochondrial and protein quality control responses to cold. In human iPSC-neurons, cold triggered mitochondrial stress, resulting in reactive oxygen species overproduction and lysosomal membrane permeabilization, contributing to microtubule destruction. Manipulations of these pathways endowed microtubule cold stability upon human iPSC-neurons and rat (a non-hibernator) retina, preserving its light responsiveness after prolonged cold exposure. Furthermore, these treatments significantly improved microtubule integrity in cold-stored kidneys, demonstrating the potential for prolonging shelf-life of organ transplants. Thus, ground squirrel iPSCs offer a unique platform for bringing cold-adaptive strategies from hibernators to humans in clinical applications. VIDEO ABSTRACT.
Assuntos
Adaptação Fisiológica , Células-Tronco Pluripotentes Induzidas/metabolismo , Neurônios/metabolismo , Animais , Diferenciação Celular , Temperatura Baixa , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Rim/efeitos dos fármacos , Rim/metabolismo , Lisossomos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Neurônios/citologia , Estresse Oxidativo , Inibidores de Proteases/farmacologia , Ratos , Espécies Reativas de Oxigênio/metabolismo , Retina/metabolismo , Sciuridae , Transcriptoma , Tubulina (Proteína)/química , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismoRESUMO
The life cycle of a primary cilium begins in quiescence and ends prior to mitosis. In quiescent cells, the primary cilium insulates itself from contiguous dynamic membrane processes on the cell surface to function as a stable signaling apparatus. Here, we demonstrate that basal restriction of ciliary structure dynamics is established by the cilia-enriched phosphoinositide 5-phosphatase, Inpp5e. Growth induction displaces ciliary Inpp5e and accumulates phosphatidylinositol 4,5-bisphosphate in distal cilia. This change triggers otherwise-forbidden actin polymerization in primary cilia, which excises cilia tips in a process we call cilia decapitation. While cilia disassembly is traditionally thought to occur solely through resorption, we show that an acute loss of IFT-B through cilia decapitation precedes resorption. Finally, we propose that cilia decapitation induces mitogenic signaling and constitutes a molecular link between the cilia life cycle and cell-division cycle. This newly defined ciliary mechanism may find significance in cell proliferation control during normal development and cancer.
Assuntos
Ciclo Celular , Cílios/metabolismo , Actinas/metabolismo , Animais , Rim/citologia , Rim/metabolismo , Camundongos , Células NIH 3T3 , Fosfatidilinositol 4,5-Difosfato , Monoéster Fosfórico Hidrolases/metabolismo , Proteína GLI1 em Dedos de Zinco/metabolismoRESUMO
Signaling receptors dynamically exit cilia upon activation of signaling pathways such as Hedgehog. Here, we find that when activated G protein-coupled receptors (GPCRs) fail to undergo BBSome-mediated retrieval from cilia back into the cell, these GPCRs concentrate into membranous buds at the tips of cilia before release into extracellular vesicles named ectosomes. Unexpectedly, actin and the actin regulators drebrin and myosin 6 mediate ectosome release from the tip of cilia. Mirroring signal-dependent retrieval, signal-dependent ectocytosis is a selective and effective process that removes activated signaling molecules from cilia. Congruently, ectocytosis compensates for BBSome defects as ectocytic removal of GPR161, a negative regulator of Hedgehog signaling, permits the appropriate transduction of Hedgehog signals in Bbs mutants. Finally, ciliary receptors that lack retrieval determinants such as the anorexigenic GPCR NPY2R undergo signal-dependent ectocytosis in wild-type cells. Our data show that signal-dependent ectocytosis regulates ciliary signaling in physiological and pathological contexts.
Assuntos
Cílios/metabolismo , Vesículas Extracelulares/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Actinas/metabolismo , Animais , Linhagem Celular , Humanos , Rim/citologia , Rim/metabolismo , Camundongos , Microscopia Eletrônica de Varredura , Receptores de Somatostatina/metabolismo , Transdução de SinaisRESUMO
The nephron is a multifunctional filtration device equipped with an array of sophisticated sensors. For appropriate physiological function in the human and mouse, nephrons must be stereotypically arrayed in large numbers, and this essential structural property that defines the kidney is determined during its fetal development. This review explores the process of nephron determination in the fetal kidney, providing an overview of the foundational literature in the field as well as exploring new developments in this dynamic research area. Mechanisms that ensure that a large number of nephrons can be formed from a small initial number of progenitor cells are central to this process, and the question of how the nephron progenitor cell population balances epithelial differentiation with renewal in the progenitor state is a subject of particular interest. Key growth factor signaling pathways and transcription factor networks are discussed.
Assuntos
Diferenciação Celular/genética , Desenvolvimento Fetal/genética , Rim/crescimento & desenvolvimento , Néfrons/crescimento & desenvolvimento , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Rim/metabolismo , Néfrons/metabolismo , Organogênese/genética , Transdução de Sinais/genética , Células-Tronco/citologiaRESUMO
The Na+-Cl- cotransporter (NCC; SLC12A3) is a highly regulated integral membrane protein that is known to exist as three splice variants in primates. Its primary role in the kidney is to mediate the cosymport of Na+ and Cl- across the apical membrane of the distal convoluted tubule. Through this role and the involvement of other ion transport systems, NCC allows the systemic circulation to reclaim a fraction of the ultrafiltered Na+, K+, Cl-, and Mg+ loads in exchange for Ca2+ and [Formula: see text]. The physiological relevance of the Na+-Cl- cotransport mechanism in humans is illustrated by several abnormalities that result from NCC inactivation through the administration of thiazides or in the setting of hereditary disorders. The purpose of the present review is to discuss the molecular mechanisms and overall roles of Na+-Cl- cotransport as the main topics of interest. On reading the narrative proposed, one will realize that the knowledge gained in regard to these themes will continue to progress unrelentingly no matter how refined it has now become.
Assuntos
Homeostase , Humanos , Animais , Homeostase/fisiologia , Membro 3 da Família 12 de Carreador de Soluto/metabolismo , Equilíbrio Hidroeletrolítico/fisiologia , Sódio/metabolismo , Rim/metabolismoRESUMO
Lupus nephritis is a potentially fatal autoimmune disease for which the current treatment is ineffective and often toxic. To develop mechanistic hypotheses of disease, we analyzed kidney samples from patients with lupus nephritis and from healthy control subjects using single-cell RNA sequencing. Our analysis revealed 21 subsets of leukocytes active in disease, including multiple populations of myeloid cells, T cells, natural killer cells and B cells that demonstrated both pro-inflammatory responses and inflammation-resolving responses. We found evidence of local activation of B cells correlated with an age-associated B-cell signature and evidence of progressive stages of monocyte differentiation within the kidney. A clear interferon response was observed in most cells. Two chemokine receptors, CXCR4 and CX3CR1, were broadly expressed, implying a potentially central role in cell trafficking. Gene expression of immune cells in urine and kidney was highly correlated, which would suggest that urine might serve as a surrogate for kidney biopsies.
Assuntos
Rim/imunologia , Nefrite Lúpica/imunologia , Biomarcadores , Biópsia , Análise por Conglomerados , Biologia Computacional/métodos , Células Epiteliais/metabolismo , Citometria de Fluxo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Imunofenotipagem , Interferons/metabolismo , Rim/metabolismo , Rim/patologia , Leucócitos/imunologia , Leucócitos/metabolismo , Nefrite Lúpica/genética , Nefrite Lúpica/metabolismo , Nefrite Lúpica/patologia , Linfócitos/imunologia , Linfócitos/metabolismo , Anotação de Sequência Molecular , Células Mieloides/imunologia , Células Mieloides/metabolismo , Análise de Célula Única , TranscriptomaRESUMO
The kidneys play a key role in maintaining total body homeostasis. The complexity of this task is reflected in the unique architecture of the organ. Ureteral obstruction greatly affects renal physiology by altering hemodynamics, changing glomerular filtration and renal metabolism, and inducing architectural malformations of the kidney parenchyma, most importantly renal fibrosis. Persisting pathological changes lead to chronic kidney disease, which currently affects â¼10% of the global population and is one of the major causes of death worldwide. Studies on the consequences of ureteral obstruction date back to the 1800s. Even today, experimental unilateral ureteral obstruction (UUO) remains the standard model for tubulointerstitial fibrosis. However, the model has certain limitations when it comes to studying tubular injury and repair, as well as a limited potential for human translation. Nevertheless, ureteral obstruction has provided the scientific community with a wealth of knowledge on renal (patho)physiology. With the introduction of advanced omics techniques, the classical UUO model has remained relevant to this day and has been instrumental in understanding renal fibrosis at the molecular, genomic, and cellular levels. This review details key concepts and recent advances in the understanding of obstructive nephropathy, highlighting the pathophysiological hallmarks responsible for the functional and architectural changes induced by ureteral obstruction, with a special emphasis on renal fibrosis.
Assuntos
Insuficiência Renal Crônica , Obstrução Ureteral , Humanos , Animais , Obstrução Ureteral/complicações , Obstrução Ureteral/patologia , Rim/metabolismo , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/metabolismo , Insuficiência Renal Crônica/patologia , Hemodinâmica , Fibrose , Modelos Animais de DoençasRESUMO
Chronic kidney disease (CKD) affects >10% of the world population, with increasing prevalence in middle age. The risk for CKD is dependent on the number of functioning nephrons through the life cycle, and 50% of nephrons are lost through normal aging, revealing their vulnerability to internal and external stressors. Factors responsible for CKD remain poorly understood, with limited availability of biomarkers or effective therapy to slow progression. This review draws on the disciplines of evolutionary medicine and bioenergetics to account for the heterogeneous nephron injury that characterizes progressive CKD following episodes of acute kidney injury with incomplete recovery. The evolution of symbiosis in eukaryotes led to the efficiencies of oxidative phosphorylation and the rise of metazoa. Adaptations to ancestral environments are the products of natural selection that have shaped the mammalian nephron with its vulnerabilities to ischemic, hypoxic, and toxic injury. Reproductive fitness rather than longevity has served as the driver of evolution, constrained by available energy and its allocation to homeostatic responses through the life cycle. Metabolic plasticity has evolved in parallel with robustness necessary to preserve complex developmental programs, and adaptations that optimize survival through reproductive years can become maladaptive with aging, reflecting antagonistic pleiotropy. Consequently, environmental stresses promote trade-offs and mismatches that result in cell fate decisions that ultimately lead to nephron loss. Elucidation of the bioenergetic adaptations by the nephron to ancestral and contemporary environments may lead to the development of new biomarkers of kidney disease and new therapies to reduce the global burden of progressive CKD.
Assuntos
Rim , Insuficiência Renal Crônica , Pessoa de Meia-Idade , Animais , Humanos , Rim/metabolismo , Néfrons/metabolismo , Insuficiência Renal Crônica/epidemiologia , Insuficiência Renal Crônica/metabolismo , Envelhecimento , Metabolismo Energético , MamíferosRESUMO
Spatial transcriptomics measures in situ gene expression at millions of locations within a tissue1, hitherto with some trade-off between transcriptome depth, spatial resolution and sample size2. Although integration of image-based segmentation has enabled impactful work in this context, it is limited by imaging quality and tissue heterogeneity. By contrast, recent array-based technologies offer the ability to measure the entire transcriptome at subcellular resolution across large samples3-6. Presently, there exist no approaches for cell type identification that directly leverage this information to annotate individual cells. Here we propose a multiscale approach to automatically classify cell types at this subcellular level, using both transcriptomic information and spatial context. We showcase this on both targeted and whole-transcriptome spatial platforms, improving cell classification and morphology for human kidney tissue and pinpointing individual sparsely distributed renal mouse immune cells without reliance on image data. By integrating these predictions into a topological pipeline based on multiparameter persistent homology7-9, we identify cell spatial relationships characteristic of a mouse model of lupus nephritis, which we validate experimentally by immunofluorescence. The proposed framework readily generalizes to new platforms, providing a comprehensive pipeline bridging different levels of biological organization from genes through to tissues.
Assuntos
Células , Perfilação da Expressão Gênica , Espaço Intracelular , Rim , Transcriptoma , Animais , Feminino , Humanos , Camundongos , Células/classificação , Células/metabolismo , Modelos Animais de Doenças , Imunofluorescência , Perfilação da Expressão Gênica/métodos , Rim/citologia , Rim/imunologia , Rim/metabolismo , Rim/patologia , Nefrite Lúpica/genética , Nefrite Lúpica/imunologia , Nefrite Lúpica/metabolismo , Nefrite Lúpica/patologia , Reprodutibilidade dos Testes , Espaço Intracelular/genética , Espaço Intracelular/metabolismoRESUMO
Over the course of more than 500 million years, the kidneys have undergone a remarkable evolution from primitive nephric tubes to intricate filtration-reabsorption systems that maintain homeostasis and remove metabolic end products from the body. The evolutionarily conserved solute carriers organic cation transporter 2 (OCT2) and organic anion transporters 1 and 3 (OAT1/3) coordinate the active secretion of a broad range of endogenous and exogenous substances, many of which accumulate in the blood of patients with kidney failure despite dialysis. Harnessing OCT2 and OAT1/3 through functional preservation or regeneration could alleviate the progression of kidney disease. Additionally, it would improve current in vitro test models that lose their expression in culture. With this review, we explore OCT2 and OAT1/3 regulation from different perspectives: phylogenetic, ontogenetic, and cell dynamic. Our aim is to identify possible molecular targets both to help prevent or compensate for the loss of transport activity in patients with kidney disease and to enable endogenous OCT2 and OAT1/3 induction in vitro in order to develop better models for drug development.
Assuntos
Rim/metabolismo , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Transportador 2 de Cátion Orgânico/metabolismo , Animais , Humanos , Nefropatias/metabolismo , FilogeniaRESUMO
Mutations in fumarate hydratase (FH) cause hereditary leiomyomatosis and renal cell carcinoma1. Loss of FH in the kidney elicits several oncogenic signalling cascades through the accumulation of the oncometabolite fumarate2. However, although the long-term consequences of FH loss have been described, the acute response has not so far been investigated. Here we generated an inducible mouse model to study the chronology of FH loss in the kidney. We show that loss of FH leads to early alterations of mitochondrial morphology and the release of mitochondrial DNA (mtDNA) into the cytosol, where it triggers the activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING)-TANK-binding kinase 1 (TBK1) pathway and stimulates an inflammatory response that is also partially dependent on retinoic-acid-inducible gene I (RIG-I). Mechanistically, we show that this phenotype is mediated by fumarate and occurs selectively through mitochondrial-derived vesicles in a manner that depends on sorting nexin 9 (SNX9). These results reveal that increased levels of intracellular fumarate induce a remodelling of the mitochondrial network and the generation of mitochondrial-derived vesicles, which allows the release of mtDNAin the cytosol and subsequent activation of the innate immune response.