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Renal inflammation and fibrosis are the common pathways leading to progressive chronic kidney disease (CKD). We previously identified hematopoietic cell kinase (HCK) as upregulated in human chronic allograft injury promoting kidney fibrosis; however, the cellular source and molecular mechanisms are unclear. Here, using immunostaining and single cell sequencing data, we show that HCK expression is highly enriched in pro-inflammatory macrophages in diseased kidneys. HCK-knockout (KO) or HCK-inhibitor decreases macrophage M1-like pro-inflammatory polarization, proliferation, and migration in RAW264.7 cells and bone marrow-derived macrophages (BMDM). We identify an interaction between HCK and ATG2A and CBL, two autophagy-related proteins, inhibiting autophagy flux in macrophages. In vivo, both global or myeloid cell specific HCK-KO attenuates renal inflammation and fibrosis with reduces macrophage numbers, pro-inflammatory polarization and migration into unilateral ureteral obstruction (UUO) kidneys and unilateral ischemia reperfusion injury (IRI) models. Finally, we developed a selective boron containing HCK inhibitor which can reduce macrophage pro-inflammatory activity, proliferation, and migration in vitro, and attenuate kidney fibrosis in the UUO mice. The current study elucidates mechanisms downstream of HCK regulating macrophage activation and polarization via autophagy in CKD and identifies that selective HCK inhibitors could be potentially developed as a new therapy for renal fibrosis. The authors previously reported HCK was associated with kidney inflammation and fibrosis. Here, they further unravel a mechanism of HCK regulating autophagy within macrophages, altering their polarization, proliferation, and migration and they also developed a more selective HCK inhibitor.

Arctigenin (ATG) is a major component of Fructus Arctii , a traditional herbal remedy that reduced proteinuria in diabetic patients. However, whether ATG specifically provides renoprotection in DKD is not known. Here we report that ATG administration is sufficient to attenuate proteinuria and podocyte injury in mouse models of diabetes. Transcriptomic analysis of diabetic mouse glomeruli showed that cell adhesion and inflammation are two key pathways affected by ATG treatment, and mass spectrometry analysis identified protein phosphatase 2 A (PP2A) as one of the top ATG-interacting proteins in renal cells. Enhanced PP2A activity by ATG reduces p65 NF-κB-mediated inflammatory response and high glucose-induced migration in cultured podocytes via interaction with Drebrin-1. Importantly, podocyte-specific Pp2a deletion in mice exacerbates DKD injury and abrogates the ATG-mediated renoprotection. Collectively, our results demonstrate a renoprotective mechanism of ATG via PP2A activation and establish PP2A as a potential target for DKD progression. Arctigenin (ATG) is the major active component of a Chinese herbal remedy known to reduce proteinuria in patients with diabetic kidney disease (DKD). Here, Zhong et al. identify PP2A as a pharmacological target of ATG in podocytes, and find that PP2A is responsible for some of the beneficial effects of ATG in mouse models of DKD.

Nephrotoxicity is a critical adverse event that leads to discontinuation of kinase inhibitor (KI) treatment. Here we show, through meta-analyses of FDA Adverse Event Reporting System, that dasatinib is associated with high risk for glomerular toxicity that is uncoupled from hypertension, suggesting a direct link between dasatinib and podocytes. We further investigate the cellular effects of dasatinib and other comparable KIs with varying risks of nephrotoxicity. Dasatinib treated podocytes show significant changes in focal adhesions, actin cytoskeleton, and morphology that are not observed with other KIs. We use phosphoproteomics and kinome profiling to identify the molecular mechanisms of dasatinib-induced injury to the actin cytoskeleton, and atomic force microscopy to quantify impairment to cellular biomechanics. Furthermore, chronic administration of dasatinib in mice causes reversible glomerular dysfunction, loss of stress fibers, and foot process effacement. We conclude that dasatinib induces nephrotoxicity through altered podocyte actin cytoskeleton, leading to injurious cellular biomechanics. Kinase inhibitors used in chemotherapy are known for their adverse effects on kidney physiology. Here, Calizo et al. show that dasatinib is associated with a higher risk of glomerular toxicity compared to other kinase inhibitors, due to deleterious effects on cytoskeletal biomechanics in podocytes.

Enhancer variants in Shroom3 associate with renal fibrosis (TIF), but with reduced albuminuria. Detailed mechanisms for these pleiotropic effects are unclear. Here, we focus on identifying the specific profibrotic Shroom3 motif and separating this from its anti-proteinuric function. Given the role for Rho-kinases (Rock) in TIF, and the interaction of Rock with Shroom3 ASD2-domain, we hypothesized that Shroom3-mediated Rock-activation is crucial for profibrotic function. To test this, we develop transgenic tools that overexpress wild-type- (WT-Sh3) or ASD2-domain deletion- Shroom3 (ASD2Δ-Sh3). During TIF, Shroom3 and Rock co-expression occur in injured tubular cells and fibroblasts. In tubular- & fibroblast- lines, ASD2Δ-Sh3 overexpression reduce Rock activation, and pro-fibrotic/pro-inflammatory transcripts downstream of TGFβ1/Wnt/Ctnnb1-signaling vs WT-Sh3. In vivo, inducible global-, or tubular-specific-, but not fibroblast-specific-, ASD2Δ-Sh3 overexpression mitigate TIF, vs WT-Sh3 overexpression. Importantly, ASD2Δ-Sh3 mice do not develop albuminuria, while overexpression of a distinct Fyn-binding deficient mutant Shroom3 (FBDM-Sh3) induces albuminuria. We then develop small molecule inhibitors of Shroom3-Rock interaction (P2Is) and confirm Rock inhibition with these agents in WT-Sh3 cell lines. Our lead P2I from these studies, BT1137, mitigates Rock-activation, profibrotic signaling and TIF in WT-Sh3 mice. Hence, we delineate the profibrotic Shroom3 motif and develop therapeutics for kidney disease from Shroom3 excess. Shroom3 genetic variants increase Shroom3 levels and promote kidney fibrosis but reduce proteinuria, complicating Shroom3 targeting for precision medicine. Here, the authors show increased fibrosis mediated by Shroom3–Rock signaling and blocking this interaction genetically or with new compounds reduces tubular Rock activation and fibrosis.

Graves disease (GD) is an autoimmune condition caused by interacting genetic and environmental factors. Genetic studies have mapped several single-nucleotide polymorphisms (SNPs) that are strongly associated with GD, but the mechanisms by which they trigger disease are unknown. We hypothesized that epigenetic modifications induced by microenvironmental influences of cytokines can reveal the functionality of GD-associated SNPs. We analyzed genome-wide histone H3 lysine 4 methylation and gene expression in thyroid cells induced by IFNα, a key cytokine secreted during viral infections, and overlapped them with known GD-associated SNPs. We mapped an open chromatin region overlapping two adjacent GD-associated SNPs (rs12101255 and rs12101261) in intron 1 of the thyroid stimulating hormone receptor (TSHR) gene. We then demonstrated that this region functions as a regulatory element through binding of the transcriptional repressor promyelocytic leukemia zinc finger protein (PLZF) at the rs12101261 site. Repression by PLZF depended on the rs12101261 disease susceptibility allele and was increased by IFNα. Intrathymic TSHR expression was decreased in individuals homozygous for the rs12101261 disease-associated genotype compared with carriers of the disease-protective allele. Our studies discovered a genetic–epigenetic interaction involving a noncoding SNP in the TSHR gene that regulates thymic TSHR gene expression and facilitates escape of TSHR-reactive T cells from central tolerance, triggering GD.

BackgroundSepsis is a life-threatening condition with high mortality. A few studies have emerged utilizing single-cell RNA sequencing (scRNA-seq) to analyze gene expression at the single-cell resolution in sepsis, but a comprehensive high-resolution analysis of blood antigen-presenting cells has not been conducted.MethodsAll published human scRNA-seq data were downloaded from the single cell portal database. After manually curating the dataset, we extracted all antigen-presenting cells, including dendritic cells (DCs) and monocytes, for identification of cell subpopulations and their gene profiling and intercellular interactions between septic patients and healthy controls. Finally, we further validated the findings by performing deconvolution analysis on bulk RNA sequencing (RNA-seq) data and flow cytometry.ResultsWithin the traditional DC populations, we discovered novel anergic DC subtypes characterized by low major histocompatibility complex class II expression. Notably, these anergic DC subtypes showed a significant increase in septic patients. Additionally, we found that a previously reported immunosuppressive monocyte subtype, Mono1, exhibited a similar gene expression profile to these anergic DCs. The consistency of our findings was confirmed through validation using bulk RNA-seq and flow cytometry, ensuring accurate identification of cell subtypes and gene expression patterns.ConclusionsThis study represents the first comprehensive single-cell analysis of antigen-presenting cells in human sepsis, revealing novel disease-associated anergic DC subtypes. These findings provide new insights into the cellular mechanisms of immune dysregulation in bacterial sepsis.

We previously demonstrated that ginsenoside Re (G-Re) has protective effects on acute kidney injury. However, the underlying mechanism is still unclear. In this study, we conducted a meta-analysis and pathway enrichment analysis of all published transcriptome data to identify differentially expressed genes (DEGs) and pathways of G-Re treatment. We then performed in vitro studies to measure the identified autophagy and fibrosis markers in HK2 cells. In vivo studies were conducted using ureteric obstruction (UUO) and aristolochic acid nephropathy (AAN) models to evaluate the effects of G-Re on autophagy and kidney fibrosis. Our informatics analysis identified autophagy-related pathways enriched for G-Re treatment. Treatment with G-Re in HK2 cells reduced autophagy and mRNA levels of profibrosis markers with TGF-β stimulation. In addition, induction of autophagy with PP242 neutralized the anti-fibrotic effects of G-Re. In murine models with UUO and AAN, treatment with G-Re significantly improved renal function and reduced the upregulation of autophagy and profibrotic markers. A combination of informatics analysis and biological experiments confirmed that ginsenoside Re could improve renal fibrosis and kidney function through the regulation of autophagy. These findings provide important insights into the mechanisms of G-Re’s protective effects in kidney injuries. Graphic abstract

Post-translational modifications have been identified to be of great importance in cancers and lysine acetylation, which can attract the multifunctional transcription factor BRD4, has been identified as a potential therapeutic target. In this paper, we identify that BRD4 has an important role in colorectal cancer; and that its inhibition substantially wipes out tumor cells. Treatment with inhibitor MS417 potently affects cancer cells, although such effects were not always outright necrosis or apoptosis. We report that BRD4 inhibition also limits distal metastasis by regulating several key proteins in the progression of epithelial-to-mesenchymal transition (EMT). This effect of BRD4 inhibitor is demonstrated via liver metastasis in animal model as well as migration and invasion experiments in vitro. Together, our results demonstrate a new application of BRD4 inhibitor that may be of clinical use by virtue of its ability to limit metastasis while also being tumorcidal.

Effective monitoring of lake aquatic environments is crucial for assessing lake health, identifying issues, and developing emergency plans. Satellite-based remote sensing has been recognized as an effective method for timely and comprehensive monitoring of these environments. However, satellite-derived products often lack complete spatial coverage due to invalid pixels resulting from factors such as cloud cover, high sun glint contamination, and high satellite-viewing angles. To address this issue, we propose a novel gap filling method for satellite-derived products of lake aquatic environments, utilizing historical big data. We initially developed a machine-learning-based model for similarity matching across various dates. This model was based on 10 factors, selected from water quality and meteorological conditions that have a significant correlation with the lake aquatic environment. This model allows for the assignment of values to invalid pixels in a specific satellite-derived product, derived from the corresponding pixels in the products of historical dates. The proposed method has been applied to the satellite-derived Chl-a products of Lake Chaohu. The experimental findings demonstrate that the computed mean value of the peak signal-to-noise ratio (PSNR) stands at 35.75, as derived from the experimental data. This substantiates the precision of the gap filling method applied to satellite-derived products. This study underscores the significant value of the proposed method in gap filling for satellite-derived products, as well as in predicting the aquatic environment of lakes.

Cholesterol 25‐hydroxylase (CH25H), an enzyme involved in cholesterol metabolism, regulates inflammatory responses and lipid metabolism. However, its role in kidney disease is not known.  The author found that CH25H transcript is expressed mostly in glomerular and peritubular endothelial cells and that its expression increased in human and mouse diabetic kidneys.  Global deletion of Ch25h in Leprdb/db mice aggravated diabetic kidney disease (DKD), which is associated with increased endothelial cell apoptosis. Treatment of 25‐hydroxycholesterol (25‐HC), the product of CH25H, alleviated kidney injury in Leprdb/db mice. Mechanistically, 25‐HC binds to GTP‐binding protein ADP‐ribosylation factor 4 (ARF4), an essential protein required for maintaining protein transport in the Golgi apparatus. Interestingly, ARF4's GTPase‐activating protein ASAP1 is also predominantly expressed in endothelial cells and its expression increased in DKD. Suppression of ARF4 activity by deleting ARF4 or overexpressing ASAP1 results in endothelial cell death. These results indicate that 25‐HC binds ARF4 to inhibit its interaction with ASAP1, and thereby resulting in enhanced ARF4 activity to confer renoprotection. Therefore, treatment of 25‐HC improves kidney injury in DKD in part by restoring ARF4 activity to maintain endothelial cell survival. This study provides a novel mechanism and a potential new therapy for DKD. This study shows that cholesterol 25‐hydroxylase (CH25H), a key enzyme in cholesterol metabolism, is expressed in kidney endothelial cells and protects against diabetic kidney disease. Its product, 25‐HC, binds to and enhances the activity of GTP‐binding protein ADP‐ribosylation factor 4 (ARF4), an essential protein required for Golgi trafficking and homeostasis, to promote endothelial cell survival and slow disease progression.