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1.
J Am Soc Nephrol ; 31(1): 118-138, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31818909

RESUMO

BACKGROUND: Renal endothelial cells from glomerular, cortical, and medullary kidney compartments are exposed to different microenvironmental conditions and support specific kidney processes. However, the heterogeneous phenotypes of these cells remain incompletely inventoried. Osmotic homeostasis is vitally important for regulating cell volume and function, and in mammals, osmotic equilibrium is regulated through the countercurrent system in the renal medulla, where water exchange through endothelium occurs against an osmotic pressure gradient. Dehydration exposes medullary renal endothelial cells to extreme hyperosmolarity, and how these cells adapt to and survive in this hypertonic milieu is unknown. METHODS: We inventoried renal endothelial cell heterogeneity by single-cell RNA sequencing >40,000 mouse renal endothelial cells, and studied transcriptome changes during osmotic adaptation upon water deprivation. We validated our findings by immunostaining and functionally by targeting oxidative phosphorylation in a hyperosmolarity model in vitro and in dehydrated mice in vivo. RESULTS: We identified 24 renal endothelial cell phenotypes (of which eight were novel), highlighting extensive heterogeneity of these cells between and within the cortex, glomeruli, and medulla. In response to dehydration and hypertonicity, medullary renal endothelial cells upregulated the expression of genes involved in the hypoxia response, glycolysis, and-surprisingly-oxidative phosphorylation. Endothelial cells increased oxygen consumption when exposed to hyperosmolarity, whereas blocking oxidative phosphorylation compromised endothelial cell viability during hyperosmotic stress and impaired urine concentration during dehydration. CONCLUSIONS: This study provides a high-resolution atlas of the renal endothelium and highlights extensive renal endothelial cell phenotypic heterogeneity, as well as a previously unrecognized role of oxidative phosphorylation in the metabolic adaptation of medullary renal endothelial cells to water deprivation.


Assuntos
Adaptação Fisiológica/genética , Células Endoteliais/metabolismo , Rim/citologia , Análise de Sequência de RNA , Privação de Água/fisiologia , Animais , Células Endoteliais/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo
2.
Commun Biol ; 7(1): 618, 2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38783087

RESUMO

Endothelial cells (ECs) are highly glycolytic, but whether they generate glycolytic intermediates via gluconeogenesis (GNG) in glucose-deprived conditions remains unknown. Here, we report that glucose-deprived ECs upregulate the GNG enzyme PCK2 and rely on a PCK2-dependent truncated GNG, whereby lactate and glutamine are used for the synthesis of lower glycolytic intermediates that enter the serine and glycerophospholipid biosynthesis pathways, which can play key roles in redox homeostasis and phospholipid synthesis, respectively. Unexpectedly, however, even in normal glucose conditions, and independent of its enzymatic activity, PCK2 silencing perturbs proteostasis, beyond its traditional GNG role. Indeed, PCK2-silenced ECs have an impaired unfolded protein response, leading to accumulation of misfolded proteins, which due to defective proteasomes and impaired autophagy, results in the accumulation of protein aggregates in lysosomes and EC demise. Ultimately, loss of PCK2 in ECs impaired vessel sprouting. This study identifies a role for PCK2 in proteostasis beyond GNG.


Assuntos
Células Endoteliais , Gluconeogênese , Fosfoenolpiruvato Carboxiquinase (GTP) , Proteostase , Gluconeogênese/genética , Humanos , Células Endoteliais/metabolismo , Fosfoenolpiruvato Carboxiquinase (GTP)/metabolismo , Fosfoenolpiruvato Carboxiquinase (GTP)/genética , Células Endoteliais da Veia Umbilical Humana/metabolismo , Glucose/metabolismo , Autofagia , Resposta a Proteínas não Dobradas , Fosfoenolpiruvato Carboxiquinase (ATP)
3.
Cell Metab ; 23(2): 280-91, 2016 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-26774962

RESUMO

The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network. Instead, PHD1(-/-) neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1(-/-) neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose away from glycolysis. As a result, PHD1(-/-) neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke.


Assuntos
Isquemia Encefálica/prevenção & controle , Reprogramação Celular , Deleção de Genes , Neurônios/metabolismo , Oxigênio/metabolismo , Pró-Colágeno-Prolina Dioxigenase/metabolismo , Acidente Vascular Cerebral/prevenção & controle , Animais , Encéfalo/irrigação sanguínea , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Isquemia Encefálica/complicações , Carbono/metabolismo , Reprogramação Celular/efeitos dos fármacos , Sequestradores de Radicais Livres/metabolismo , Hidroxilação , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Injeções Intraventriculares , Camundongos Knockout , Neurônios/efeitos dos fármacos , Neuroproteção/efeitos dos fármacos , Oligonucleotídeos/administração & dosagem , Oligonucleotídeos/farmacologia , Oxirredução/efeitos dos fármacos , Via de Pentose Fosfato/efeitos dos fármacos , Fenótipo , Pró-Colágeno-Prolina Dioxigenase/deficiência , Espécies Reativas de Oxigênio/metabolismo , Acidente Vascular Cerebral/complicações
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