Rheb1 deficiency elicits mitochondrial dysfunction and accelerates podocyte senescence through promoting Atp5f1c acetylation.

Podocyte senescence can cause persistent podocyte injury and albuminuria in diabetic kidney disease (DKD), but the mechanism remains obscure. In this study, podocyte senescence was confirmed by immunohistochemical staining in podocytes from patients and mice with DKD. Rheb1 knockout in podocytes aggravated podocyte senescence and injury in diabetic mice, but mitigated podocyte injury in mice with podocyte-specific mTORC1 activation induced by Tsc1 deletion.

Association of Serum Unsaturated Fatty Acid Patterns with the Risk of Diabetic Nephropathy.

Introduction: Unsaturated fatty acids play an essential role in the progression of diabetic nephropathy (DN). However, previous studies were mainly focused on the role of individual unsaturated fatty acid. The serum unsaturated fatty acid patterns (FAPs) in patients with DN remain to be determined.

Fecal microbiota transplantation ameliorates type 2 diabetes via metabolic remodeling of the gut microbiota in db/db mice.

Introduction: Gut microbiome (GM) deregulation has been implicated in major conditions such as obesity and type 2 diabetes (T2DM). Our previous prospective study indicated that fecal microbiota transplantation (FMT) successfully improved patients with T2DM. We hypothesized that FMT may be a potential therapeutic method for T2DM, but its precise mechanisms in T2DM remains to be elucidated.

Mechanistic target of rapamycin complex 1 orchestrates the interplay between hepatocytes and Kupffer cells to determine the outcome of immune-mediated hepatitis.

The cell-cell interaction between hepatocytes and Kupffer cells (KCs) is crucial for maintaining liver homeostasis, and the loss of KCs and hepatocytes is known to represent a common pathogenic phenomenon in autoimmune hepatitis. Until now, the mechanisms of cell-cell interaction between hepatocytes and KCs involved in immune-mediated hepatitis remains unclear. Here we dissected the impact of activated mTORC1 on the cell-cell interaction of KCs and hepatocyte in immune-mediated hepatitis.

Protein phosphatase 2Acα modulates fatty acid oxidation and glycolysis to determine tubular cell fate and kidney injury.

Energy metabolism is crucial in maintaining cellular homeostasis and adapting to stimuli for tubular cells. However, the underlying mechanisms remain largely unknown. Here, we report that PP2Acα was upregulated in damaged tubular cells from patients and animal models with acute or chronic kidney injury.

PP2A Catalytic Subunit α promotes fibroblast activation and kidney fibrosis via ERK pathway.

Protein Phosphatase 2A (PP2A), a main serine/threonine phosphatase, plays a profibrotic role in the development of different organs. However, the role and mechanisms of PP2Acα in fibroblast activation and kidney fibrosis are not fully known. Here we found that PP2Acα expression was upregulated in kidney tissue of chronic kidney disease (CKD) patients and unilateral ureter obstructive (UUO) mice.

Complement factor B in high glucose-induced podocyte injury and diabetic kidney disease.

The role and mechanisms for upregulating complement factor B (CFB) expression in podocyte dysfunction in diabetic kidney disease (DKD) are not fully understood. Here, analyzing Gene Expression Omnibus GSE30528 data, we identified genes enriched in mTORC1 signaling, CFB, and complement alternative pathways in podocytes from patients with DKD. In mouse models, podocyte mTOR complex 1 (mTORC1) signaling activation was induced, while blockade of mTORC1 signaling reduced CFB upregulation, alternative complement pathway activation, and podocyte injury in the glomeruli.

PP2Acα promotes macrophage accumulation and activation to exacerbate tubular cell death and kidney fibrosis through activating Rap1 and TNFα production.

Macrophage accumulation and activation play an essential role in kidney fibrosis; however, the underlying mechanisms remain to be explored. By analyzing the kidney tissues from patients and animal models with kidney fibrosis, we found a large induction of PP2Acα in macrophages. We then generated a mouse model with inducible macrophage ablation of PP2Acα.

Loss of Rictor in tubular cells exaggerates lipopolysaccharide induced renal inflammation and acute kidney injury via Yap/Taz-NF-κB axis.

Our previous study demonstrated that the mammalian target of rapamycin complex 2 (mTORC2) signaling alleviates renal inflammation and protects against cisplatin-induced AKI. However, the underlying mechanisms for mTORC2 in regulating renal inflammation in AKI remain to be determined. In this study, we found that lipopolysaccharide (LPS) could activate mTORC2 signaling in NRK-52E cells, and blockage of mTORC2 signaling led to Yap/Taz degradation, which in turn activated NF-κB signaling and induced inflammatory cytokines secretion.

Rheb1 protects against cisplatin-induced tubular cell death and acute kidney injury via maintaining mitochondrial homeostasis.

Ras homolog enriched in brain (Rheb1), a small GTPase, plays a crucial role in regulating cell growth, differentiation, and survival. However, the role and mechanisms for Rheb1 in tubular cell survival and acute kidney injury (AKI) remain unexplored. Here we found that Rheb1 signaling was activated in kidney tubule of AKI patients and cisplatin-treated mice.

Fibroblast mTOR/PPARγ/HGF axis protects against tubular cell death and acute kidney injury.

Kidney fibroblasts play a crucial role in dictating tubular cell fate and the outcome of acute kidney injury (AKI). The underlying mechanisms remain to be determined. Here, we found that mTOR signaling was activated in fibroblasts from mouse kidneys with ischemia/reperfusion injury (IRI).

The signaling protein Wnt5a promotes TGFβ1-mediated macrophage polarization and kidney fibrosis by inducing the transcriptional regulators Yap/Taz.

M2 macrophage polarization is known to underlie kidney fibrosis. We previously reported that most of the members of the Wnt family of signaling proteins are induced in fibrotic kidneys. Dysregulation of the signaling protein Wnt5a is associated with fibrosis, but little is known about the role of Wnt5a in regulating M2 macrophage activation that results in kidney fibrosis.

Yap/Taz mediates mTORC2-stimulated fibroblast activation and kidney fibrosis.

Our previously published study demonstrated that mammalian target of rapamycin complex 2 (mTORC2) signaling mediates TGFβ1-induced fibroblast activation. However, the underlying mechanisms for mTORC2 in stimulating fibroblast activation remain poorly understood. Here, we found that TGFβ1 could stimulate mTORC2 and Yap/Taz activation in NRK-49F cells.

Protein kinase Cα drives fibroblast activation and kidney fibrosis by stimulating autophagic flux.

Kidney fibrosis is a histological hallmark of chronic kidney disease and arises in large part through extracellular matrix deposition by activated fibroblasts. The signaling protein complex mTOR complex 2 (mTORC2) plays a critical role in fibroblast activation and kidney fibrosis. Protein kinase Cα (PKCα) is one of the major sub-pathways of mTORC2, but its role in fibroblast activation and kidney fibrosis remains to be determined.

Blockade of CD38 diminishes lipopolysaccharide-induced macrophage classical activation and acute kidney injury involving NF-κB signaling suppression.

The CD38, possessing ADP-ribosyl cyclase (ADPR-cyclase) and cyclic ADP-ribose hydrolase (cADPR-hydrolase), is able to regulate a variety of cellular activities. However, the role and mechanisms for CD38 in macrophage activation and sepsis-induced acute kidney injury (AKI) remain to be determined. Here we report that in cultured macrophages, Lipopolysaccharide (LPS) could upregulate CD38 expression in time and dose dependent manner.

Wnt/-Catenin-Promoted Macrophage Alternative Activation Contributes to Kidney Fibrosis.

The Wnt/-catenin pathway is crucial in normal development and throughout life, but aberrant activation of this pathway has been linked to kidney fibrosis, although the mechanisms involved remain incompletely determined. Here, we investigated the role of Wnt/-catenin in regulating macrophage activation and the contribution thereof to kidney fibrosis. Treatment of macrophages with Wnt3a exacerbated IL-4- or TGF1-induced macrophage alternative (M2) polarization and the phosphorylation and nuclear translocation of STAT3 Conversely, inhibition of Wnt/-catenin signaling prevented these IL-4- or TGF1-induced processes.