Reciprocal regulation between the molecular clock and kidney injury

Molecular clock; Kidney injuryRellotge molecular; Lesió renalReloj molecular; Lesión renalTubulointerstitial fibrosis is the common pathological substrate for many etiologies leading to chronic kidney disease. Although perturbations in the circadian rhythm have been associated with renal disease, the role of the molecular clock in the pathogenesis of fibrosis remains incompletely understood. We investigated the relationship between the molecular clock and renal damage in experimental models of injury and fibrosis (unilateral ureteral obstruction, folic acid, and adenine nephrotoxicity), using genetically modified mice with selective deficiencies of the clock components Bmal1, Clock, and Cry. We found that the molecular clock pathway was enriched in damaged tubular epithelial cells with marked metabolic alterations. In human tubular epithelial cells, TGFβ significantly altered the expression of clock components. Although Clock played a role in the macrophage-mediated inflammatory response, the combined absence of Cry1 and Cry2 was critical for the recruitment of neutrophils, correlating with a worsening of fibrosis and with a major shift in the expression of metabolism-related genes. These results support that renal damage disrupts the kidney peripheral molecular clock, which in turn promotes metabolic derangement linked to inflammatory and fibrotic responses.This work was supported by grants from the Ministerio de Ciencia e Innovación PID2019-104233RB-100/AEI/10.13039/501100011033 (S Lamas), Instituto de Salud Carlos III REDinREN RD12/0021/0009 and RD16/0009/0016 (S Lamas), Comunidad de Madrid “NOVELREN” B2017/BMD-3751 and INNOREN P2022/BMD-7221 (S Lamas and C Barbas), and Fundación Renal “Iñigo Alvarez de Toledo” (S Lamas), all from Spain. C Rey-Serra has been the recipient of an FPI research training contract from the Spanish Research State Agency (BES-2016-076735). The CBMSO receives institutional support from Fundación “Ramón Areces.” We acknowledge the laboratories of Fernando Rodríguez Pascual (CBMSO) for helping with plasmid constructions and of Marta Ruiz‐Ortega at the Fundación Jiménez Díaz for helping with immunohistochemistry. We also acknowledge the help of the following facilities of the CBMSO: animal housing, flow cytometry, and confocal and electron microscopy

Análisis crítico de la dimensión ambiental del ecosistema montañoso Guamuhaya, Cuba (1995-2014)

El progresivo deterioro de las condiciones ambientales, económicas y sociales, que sufren los ecosistemas de montaña, revela la urgente necesidad de desarrollar acciones para su conservación. Es objetivo de esta investigación, realizar un análisis crítico retrospectivo sobre el comportamiento de indicadores identificados por expertos, en la dimensión ambiental del ecosistema montañoso Guamuhaya (Cienfuegos), Cuba, (1995-2014). Con la ayuda de métodos estadísticos matemáticos, se realizó un pronóstico para el Índice de calidad del agua, por ser uno de los indicadores más representativos de esta dimensión, contribuyendo a su proyección futura y al diseño de estrategias que favorezcan la sostenibilidad local

Reciprocal regulation between the molecular clock and kidney injury

Tubulointerstitial fibrosis is the common pathological substrate for many etiologies leading to chronic kidney disease. Although perturbations in the circadian rhythm have been associated with renal disease, the role of the molecular clock in the pathogenesis of fibrosis remains incompletely understood. We investigated the relationship between the molecular clock and renal damage in experimental models of injury and fibrosis (unilateral ureteral obstruction, folic acid, and adenine nephrotoxicity), using genetically modified mice with selective deficiencies of the clock components Bmal1, Clock, and Cry. We found that the molecular clock pathway was enriched in damaged tubular epithelial cells with marked metabolic alterations. In human tubular epithelial cells, TGFβ significantly altered the expression of clock components. Although Clock played a role in the macrophage-mediated inflammatory response, the combined absence of Cry1 and Cry2 was critical for the recruitment of neutrophils, correlating with a worsening of fibrosis and with a major shift in the expression of metabolism-related genes. These results support that renal damage disrupts the kidney peripheral molecular clock, which in turn promotes metabolic derangement linked to inflammatory and fibrotic responses.This work was supported by grants from the Ministerio de Ciencia e Innovación PID2019-104233RB-100/AEI/10.13039/501100011033 (S Lamas), Instituto de Salud Carlos III REDinREN RD12/0021/0009 and RD16/0009/0016 (S Lamas), Comunidad de Madrid “NOVELREN” B2017/BMD-3751 and INNOREN P2022/BMD-7221 (S Lamas and C Barbas), and Fundación Renal “Iñigo Alvarez de Toledo” (S Lamas), all from Spain. C Rey-Serra has been the recipient of an FPI research training contract from the Spanish Research State Agency (BES-2016-076735). The CBMSO receives institutional support from Fundación “Ramón Areces.

Renal tubule Cpt1a overexpression protects from kidney fibrosis by restoring mitochondrial homeostasis

Chronic kidney disease (CKD) remains a major epidemiological, clinical, and biomedical challenge. During CKD, renal tubular epithelial cells (TECs) present a persistent inflammatory and profibrotic response. Fatty acid oxidation (FAO), the main source of energy for TECs, is reduced in kidney fibrosis and contributes to its pathogenesis. To determine whether gain of function in FAO (FAO-GOF) could protect from fibrosis, we generated a conditional transgenic mouse model with overexpression of the fatty acid shuttling enzyme carnitine palmitoyl-transferase 1A (CPT1A) in TECs. Cpt1a-knockin (CPT1A-KI) mice subjected to 3 models of renal fibrosis (unilateral ureteral obstruction, folic acid nephropathy [FAN], and adenine-induced nephrotoxicity) exhibited decreased expression of fibrotic markers, a blunted proinflammatory response, and reduced epithelial cell damage and macrophage influx. Protection from fibrosis was also observed when Cpt1a overexpression was induced after FAN. FAO-GOF restored oxidative metabolism and mitochondrial number and enhanced bioenergetics, increasing palmitate oxidation and ATP levels, changes that were also recapitulated in TECs exposed to profibrotic stimuli. Studies in patients showed decreased CPT1 levels and increased accumulation of short- and middle-chain acylcarnitines, reflecting impaired FAO in human CKD. We propose that strategies based on FAO-GOF may constitute powerful alternatives to combat fibrosis inherent to CKD

MiR‐9‐5p protects from kidney fibrosis by metabolic reprogramming

MicroRNAs (miRNAs) regulate gene expression posttranscriptionally and control biological processes (BPs), including fibrogenesis. Kidney fibrosis remains a clinical challenge and miRNAs may represent a valid therapeutic avenue. We show that miR‐9‐5p protected from renal fibrosis in the mouse model of unilateral ureteral obstruction (UUO). This was reflected in reduced expression of pro‐fibrotic markers, decreased number of infiltrating monocytes/macrophages, and diminished tubular epithelial cell injury and transforming growth factor‐beta 1 (TGF‐β1)‐dependent de‐differentiation in human kidney proximal tubular (HKC‐8) cells. RNA‐sequencing (RNA‐Seq) studies in the UUO model revealed that treatment with miR‐9‐5p prevented the downregulation of genes related to key metabolic pathways, including mitochondrial function, oxidative phosphorylation (OXPHOS), fatty acid oxidation (FAO), and glycolysis. Studies in human tubular epithelial cells demonstrated that miR‐9‐5p impeded TGF‐β1‐induced bioenergetics derangement. The expression of the FAO‐related axis peroxisome proliferator‐activated receptor gamma coactivator 1 alpha (PGC‐1α)‐peroxisome proliferator‐activated receptor alpha (PPARα) was reduced by UUO, although preserved by the administration of miR‐9‐5p. We found that in mice null for the mitochondrial master regulator PGC‐1α, miR‐9‐5p was unable to promote a protective effect in the UUO model. We propose that miR‐9‐5p elicits a protective response to chronic kidney injury and renal fibrosis by inducing reprogramming of the metabolic derangement and mitochondrial dysfunction affecting tubular epithelial cells.This work was supported by Grants from the Ministerio de Economía y Competitividad (MINECO) SAF 2012‐31388 (SL) and SAF2015‐66107‐R (SL), both cofunded by the European Regional Development Fund, Instituto de Salud Carlos III REDinREN RD12/0021/0009 and RD16/0009/0016 (SL and MRO), PI17/00119 (MRO), SAF2015‐63904‐R (MM), cofunded by the European Regional Development Fund, European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska‐Curie grant agreement 721236‐TREATMENT (MM), Comunidad de Madrid “NOVELREN” B2017/BMD­3751 (SL and MRO), and Fundación Renal “Iñigo Alvarez de Toledo” (SL), all from Spain. The CBMSO receives institutional support from Fundación “Ramón Areces”. VM and CNT were supported by predoctoral fellowships of the FPI Program (BES‐2013‐065986 and BES‐2014‐068929) from MINECO.Peer reviewe

Enhanced fatty acid oxidation through metformin and baicalin as therapy for COVID-19 and associated inflammatory states in lung and kidney

Progressive respiratory failure is the primary cause of death in the coronavirus disease 2019 (COVID-19) pandemic. It is the final outcome of the acute respiratory distress syndrome (ARDS), characterized by an initial exacerbated inflammatory response, metabolic derangement and ultimate tissue scarring. A positive balance of cellular energy may result crucial for the recovery of clinical COVID-19. Hence, we asked if two key pathways involved in cellular energy generation, AMP-activated protein kinase (AMPK)/acetyl-CoA carboxylase (ACC) signaling and fatty acid oxidation (FAO) could be beneficial. We tested the drugs metformin (AMPK activator) and baicalin (CPT1A activator) in different experimental models mimicking COVID-19 associated inflammation in lung and kidney. We also studied two different cohorts of COVID-19 patients that had been previously treated with metformin. These drugs ameliorated lung damage in an ARDS animal model, while activation of AMPK/ACC signaling increased mitochondrial function and decreased TGF-β-induced fibrosis, apoptosis and inflammation markers in lung epithelial cells. Similar results were observed with two indole derivatives, IND6 and IND8 with AMPK activating capacity. Consistently, a reduced time of hospitalization and need of intensive care was observed in COVID-19 patients previously exposed to metformin. Baicalin also mitigated the activation of pro-inflammatory bone marrow-derived macrophages (BMDMs) and reduced kidney fibrosis in two animal models of kidney injury, another key target of COVID-19. In human epithelial lung and kidney cells, both drugs improved mitochondrial function and prevented TGF-β-induced renal epithelial cell dedifferentiation. Our results support that favoring cellular energy production through enhanced FAO may prove useful in the prevention of COVID-19-induced lung and renal damage