Depletion of CUL4B in macrophages ameliorates diabetic kidney disease via miR-194-5p/ITGA9 axis

GPX4 deficiency-induced ferroptosis drives endometrial epithelial fibrosis in polycystic ovary syndrome

The increased risk of infertility and endometrial lesions (such as endometrial hyperplasia or cancer) in polycystic ovary syndrome (PCOS) are closely associated with the lack of cyclical transformation in the endometrium. However, the underlying mechanisms remain incompletely understood. Though integrating single-cell RNA-sequencing, transcriptomics, and metabolomics analysis, we found that glutathione (GSH) metabolism disorder and the overactivation of ferroptosis, triggered by glutathione peroxidase 4 (GPX4) deficiency in endometrial epithelial cells, were the consequences of the prolonged endometrial proliferative phase in PCOS. This change may collectively contribute to some extent to decidualization failure. We further performed GSVA analysis and determined that the negative correlation between ferroptosis and fibrosis-related pathway was the most significant. Therefore, we first confirmed the presence of fibrosis in the proliferative endometrium of PCOS and PCOS-like mouse uteri. Additionally, by establishing endometrial organoids (EEOs) models and in vitro cell line models, we demonstrated that GPX4 deficiency contributed to extracellular matrix remodeling and excessive collagen deposition, via activating the TGF-β1/Smad2/3 pathway, which ultimately accelerated fibrosis. GSH intervention to the EEOs of PCOS could alleviate their fibrotic phenotypes at different stages. These findings may serve as a promising therapeutic target for PCOS-related endometrial dysfunction, as well as valuable strategies for improving PCOS-related adverse pregnancy outcomes.

Salvia miltiorrhiza-derived exosome-like nanoparticles improve diabetic cardiomyopathy by inhibiting NLRP3 inflammasome-mediated macrophage pyroptosis via targeting the NEDD4/SGK1 axis

AIM

Exosome-like nanoparticles mediate intercellular communication and regulate gene expression. In this study, we isolated and purified exosome-like nanoparticles from Salvia miltiorrhiza (SM-ELNs), a traditional Chinese medicinal herb, and investigated their therapeutic effects on diabetic cardiomyopathy (DCM).

MATERIALS & METHODS

To investigate the effect of SM-ELNs on DCM, we established a mouse model via HFD/STZ treatment. Cardiac function was assessed by echocardiography. Cardiac hypertrophy was assessed by measuring the heart weight/body weight ratio and HE staining, while myocardial fibrosis was evaluated using Masson's trichrome staining. The role of SM-ELNs on NLRP3 inflammasome inhibition and macrophage pyroptosis were evaluated both in vivo and in vitro. The interaction between NEDD4 and SGK1 was analyzed by Co-IP and ubiquitination assays.

RESULTS

SM-ELNs treatment alleviated cardiac function and histopathological changes in DCM mice. Moreover, SM-ELNs suppressed NLRP3 inflammasome activation and subsequent macrophage pyroptosis in both in vivo and in vitro models. Mechanistically, NEDD4 facilitated the ubiquitination and degradation of SGK1 in macrophages. Both NEDD4 depletion and SGK1 addition could counteract the SM-ELNs-induced suppression of NLRP3 inflammasome-triggered macrophage pyroptosis in LPS/ATP-treated RAW264.7 cells.

CONCLUSION

Our study provides the first evidence that SM-ELNs inhibit NLRP3 inflammasome-mediated macrophage pyroptosis in DCM by modulating the NEDD4/SGK1 axis.

Transcriptomic analysis after SARS-CoV-2 mRNA vaccination reveals a specific gene signature in low-responder hemodialysis patients

Introduction

Individuals with comorbidities, such as chronic kidney disease and hemodialysis patients (HDP), are particularly susceptible to severe COVID-19 and to its complications. Furthermore, their immune response to vaccines is impaired, requiring tailored vaccination strategies. In this study, we investigated through transcriptomic profiling the immune response heterogeneity of HDP vaccinated with two doses of mRNA BNT162b2 vaccine.

Methods

Transcriptomic analyses were conducted in peripheral blood mononuclear cells (PBMC) collected from HDP and healthy controls (HC) before and 7 days after each dose. The HDP were stratified into high- and low-responders based on their humoral response after the second dose.

Results

Significant differences in gene expression related to B cell abundance and regulation, CD4 T cell proliferation, and inflammation pathways were observed at baseline and day 7 between HDP-low responders and HC, while the HDP high-responders displayed an intermediate expression profile for these genes.

Discussion

Results were consistent with the known immunologic alterations occurring in HDP cohorts related to lymphopenia, chronic inflammation, and dysregulated proliferation of CD4+. Our analyses identified an early transcriptional signature correlated with a diminished immune response in HDP low-responders, highlighting the importance of conducting a characterization of immunocompromised cohorts.

Elucidating the immunomodulatory roles and mechanisms of CUL4B in the immune system: a comprehensive review

Cullin 4B (CUL4B), a pivotal member of the Cullins protein family, plays a crucial role in immune regulation and has garnered significant research attention. CUL4B, through the Cullin 4B-RING E3 ubiquitin ligase (CRL4B) complex, regulates CD4+ T cell differentiation, fostering a balance between TH1 and TH2 subsets, and expedites DNA damage repair to bolster T cell persistence. In B cells, CUL4B upregulation stimulates immune responses but is linked to an unfavorable prognosis in lymphoma. In innate immunity, CUL4B modulates Toll-like receptor (TLR)-mediated anti-inflammatory responses, enhancing macrophage migration and adhesion. CUL4B also plays a role in potentiating anti-tumor immunity by restricting the activity of myeloid-derived suppressor cells (MDSCs). In disease pathogenesis, CUL4B limits MDSCs to enhance anti-tumor effects, and its inhibition in experimental autoimmune encephalomyelitis (EAE) models have demonstrated beneficial effects, underscoring its potential therapeutic significance in autoimmune diseases. Furthermore, CUL4B is involved in various immune-related cancers and inflammation, including pleural mesothelioma, human osteosarcoma, and colitis-associated cancer. In metabolic diseases, CUL4B regulates adipose tissue and insulin sensitivity, with its depletion improving metabolic phenotypes. This review highlights the pivotal role of CUL4B in maintaining immune homeostasis and provides novel perspectives and insights into the understanding and development of treatments for immune-related disorders.

Scaffold Proteins in Fibrotic Diseases of Visceral Organs

Fibrosis, characterized by excessive extracellular matrix (ECM) deposition, disrupts tissue architecture and impairs organ function, ultimately leading to severe health consequences and even failure of vital organs such as the lung, heart, liver, and kidney. Despite significant advances in understanding the molecular mechanisms underlying fibrosis, effective therapeutic options remain limited. Emerging evidence highlights scaffold proteins as critical regulators in the progression of fibrosis. These multifunctional proteins serve as molecular platforms that organize and coordinate key signaling pathways-including those governing ECM remodeling, cytoskeletal organization, and cell migration-thereby integrating both profibrotic and antifibrotic signals. Their pivotal role in linking mechanotransduction, inflammatory, and developmental signals offers a unique therapeutic window, as targeted interventions (e.g., small-molecule inhibitors, peptides, biologics, and gene therapy) are emerging to modulate these pathways. This review synthesizes recent findings on scaffold protein functions across multiple organs and discusses novel therapeutic strategies to manage and potentially reverse fibrosis.

Epigenetic regulation of macrophage function in kidney disease: New perspective on the interaction between epigenetics and immune modulation

The interaction between renal intrinsic cells and macrophages plays a crucial role in the onset and progression of kidney diseases. In recent years, epigenetic mechanisms such as DNA methylation, histone modification, and non-coding RNA regulation have become essential windows for understanding these processes. This review focuses on how renal intrinsic cells (including tubular epithelial cells, podocytes, and endothelial cells), renal cancer cells, and mesenchymal stem cells influence the function and polarization status of macrophages through their own epigenetic alterations, and how the epigenetic regulation of macrophages themselves responds to kidney damage, thus participating in renal inflammation, fibrosis, and repair. Moreover, therapeutic studies targeting these epigenetic interaction mechanisms have found that the application of histone deacetylase inhibitors, histone methyltransferase inhibitors, various nanomaterials, and locked nucleic acids against non-coding RNA have positive effects on the treatment of multiple kidney diseases. This review summarizes the latest research advancements in these epigenetic regulatory mechanisms and therapies, providing a theoretical foundation for further elucidating the pathogenesis of kidney diseases and the development of novel therapeutic strategies.

Cullin 4B-RING E3 ligase negatively regulates the immunosuppressive capacity of mesenchymal stem cells by suppressing iNOS

Mesenchymal stem cells (MSCs) are multipotent stem cells that can exert immunomodulatory capacity upon stimulation with pro-inflammatory cytokines. Our previous work has identified Cullin 4B (CUL4B), a scaffold protein in the CUL4B-RING E3 ligase (CRL4B) complex, as a key regulator in the differentiation of MSCs. Here, we demonstrate the critical role of CUL4B in regulating the immunosuppressive function of MSCs. When stimulated with pro-inflammatory cytokines, MSCs lacking CUL4B display enhanced immunosuppressive capacity, which is mediated by the elevated inducible nitric oxide synthase (iNOS). TGF-β signaling can suppress iNOS by inhibiting its transcription as well as promoting its protein degradation. We show that the CRL4B complex cooperates with PRC2 complex and HDACs to repress transcription of Dlx1 and Pmepa1, two inhibitors of TGF-β signaling, leading to decreased expression and accelerated degradation of iNOS. Our study unveils the CRL4B complex as a potential therapeutic target in promoting the immunosuppressive capacity of MSCs.

CUL4B protects kidneys from acute injury by restraining p53/PAI-1 signaling

Acute kidney injury (AKI) caused by nephrotoxins, ischemia reperfusion (IR) or sepsis is associated with high morbidity and mortality. Unveiling new mechanisms underlying AKI can help develop new therapeutic strategy. Cullin 4B (CUL4B) is a scaffold protein in the CUL4B-RING E3 ubiquitin ligase (CRL4B) complex. Here, we demonstrate that CUL4B can protect kidneys from acute injury induced by cisplatin and IR. CUL4B is upregulated in mouse tubular epithelial cells (TECs) after cisplatin treatment or IR. Loss of CUL4B in kidneys exacerbates renal injury, inflammation, and apoptosis of TECs caused by cisplatin and IR. Transcriptome analysis reveals that Cul4b deficiency enhances injury-induced PAI-1 expression. CUL4B suppresses PAI-1 expression by promoting polyubiquitination and degradation of p53. Inhibition of either PAI-1 or p53 can prevent the aggravated renal injury and inflammation caused by loss of CUL4B. Our work has identified the kidney-protective role of CUL4B against acute injury.

Endothelial metabolic control of insulin sensitivity through resident macrophages

Endothelial cells (ECs) not only form passive blood conduits but actively contribute to nutrient transport and organ homeostasis. The role of ECs in glucose homeostasis is, however, poorly understood. Here, we show that, in skeletal muscle, endothelial glucose transporter 1 (Glut1/Slc2a1) controls glucose uptake via vascular metabolic control of muscle-resident macrophages without affecting transendothelial glucose transport. Lowering endothelial Glut1 via genetic depletion (Glut1ΔEC) or upon a short-term high-fat diet increased angiocrine osteopontin (OPN/Spp1) secretion. This promoted resident muscle macrophage activation and proliferation, which impaired muscle insulin sensitivity. Consequently, co-deleting Spp1 from ECs prevented macrophage accumulation and improved insulin sensitivity in Glut1ΔEC mice. Mechanistically, Glut1-dependent endothelial glucose metabolic rewiring increased OPN in a serine metabolism-dependent fashion. Our data illustrate how the glycolytic endothelium creates a microenvironment that controls resident muscle macrophage phenotype and function and directly links resident muscle macrophages to the maintenance of muscle glucose homeostasis.

Identification of crucial genes and possible molecular pathways associated with active vitamin D intervention in diabetic kidney disease

Background

A significant cause of advanced renal failure is diabetic nephropathy (DKD), with few treatment options available. Calcitriol shows potential in addressing fibrosis related to DKD, though its molecular mechanisms remain poorly understood. This research seeks to pinpoint the crucial genes and pathways influenced by calcitriol within the scope of DKD-related fibrosis.

Methods

Single-cell gene expression profiling of calcitriol treated DKD rat kidney tissue and screening of fibrosis-associated cell subsets. Mendelian randomization and enrichment analyses (CIBERSORT, GSVA, GSEA, Motif Enrichment) were used to explore gene-immune cell interactions and signaling pathways. Key findings were validated using independent datasets and protein expression data from the Human Protein Atlas.

Results

Calcitriol treatment reduced proliferative cell populations and highlighted the FoxO signaling pathway's role in DKD. SUMO3 and CD74 were identified as key markers linked to immune infiltration and renal function. These genes were significantly associated with creatinine levels and eGFR, indicating their potential role in DKD progression.

Conclusion

Our results suggest that calcitriol modulates DKD fibrosis through the FoxO pathway, with SUMO3 and CD74 serving as potential biomarkers for kidney protection. These results provide fresh insights into strategies for treating DKD.

Disease activity drives divergent epigenetic and transcriptomic reprogramming of monocyte subpopulations in systemic lupus erythematosus

OBJECTIVES

Systemic lupus erythematosus (SLE) is characterised by systemic inflammation involving various immune cell types. Monocytes, pivotal in promoting and regulating inflammation in SLE, differentiate from classic monocytes into intermediate and non-classic monocytes, assuming diverse roles and changing their proportions in inflammation. In this study, we investigated the epigenetic and transcriptomic profiles of these and novel monocyte subsets in SLE in relation to activity and progression.

METHODS

We obtained the DNA methylomes and transcriptomes of classic, intermediate, non-classic monocytes in patients with SLE (at first and follow-up visits) and healthy donors. We integrated these data with single-cell transcriptomics of SLE and healthy donors and interrogated their relationships with activity and progression.

RESULTS

In addition to shared DNA methylation and transcriptomic alterations associated with a strong interferon signature, we identified monocyte subset-specific alterations, especially in DNA methylation, which reflect an impact of SLE on monocyte differentiation. SLE classic monocytes exhibited a proinflammatory profile and were primed for macrophage differentiation. SLE non-classic monocytes displayed a T cell differentiation-related phenotype, with Th17-regulating features. Changes in monocyte proportions, DNA methylation and expression occurred in relation to disease activity and involved the STAT pathway. Integration of bulk with single-cell RNA sequencing datasets revealed disease activity-dependent expansion of SLE-specific monocyte subsets, further supported the interferon signature for classic monocytes, and associated intermediate and non-classic populations with exacerbated complement activation.

CONCLUSIONS

Disease activity in SLE drives a subversion of the epigenome and transcriptome programme in monocyte differentiation, impacting the function of different subsets and allowing to generate predictive methods for activity and progression.

Identification of ligand and receptor interactions in CKD and MASH through the integration of single cell and spatial transcriptomics

BACKGROUND

Chronic Kidney Disease (CKD) and Metabolic dysfunction-associated steatohepatitis (MASH) are metabolic fibroinflammatory diseases. Combining single-cell (scRNAseq) and spatial transcriptomics (ST) could give unprecedented molecular disease understanding at single-cell resolution. A more comprehensive analysis of the cell-specific ligand-receptor (L-R) interactions could provide pivotal information about signaling pathways in CKD and MASH. To achieve this, we created an integrative analysis framework in CKD and MASH from two available human cohorts.

RESULTS

The analytical framework identified L-R pairs involved in cellular crosstalk in CKD and MASH. Interactions between cell types identified using scRNAseq data were validated by checking the spatial co-presence using the ST data and the co-expression of the communicating targets. Multiple L-R protein pairs identified are known key players in CKD and MASH, while others are novel potential targets previously observed only in animal models.

CONCLUSION

Our study highlights the importance of integrating different modalities of transcriptomic data for a better understanding of the molecular mechanisms. The combination of single-cell resolution from scRNAseq data, combined with tissue slide investigations and visualization of cell-cell interactions obtained through ST, paves the way for the identification of future potential therapeutic targets and developing effective therapies.

Hyperbaric oxygen therapy promotes the browning of white fat and contributes to the healing of diabetic wounds

Non-healing wounds are one of the chronic complications of diabetes and have remained a worldwide challenge as one of the major health problems. Hyperbaric oxygen (HBO) therapy is proven to be very successful for diabetic wound treatment, for which the molecular basis is not understood. Adipocytes regulate multiple aspects of repair and may be therapeutic for inflammatory diseases and defective wound healing associated with aging and diabetes. Endothelial cell-derived extracellular vesicles could promote wound healing in diabetes. To study the mechanism by which HBO promotes wound healing in diabetes, we investigated the effect of HBO on fat cells in diabetic mice. A diabetic wound mouse model was established and treated with HBO. Haematoxylin and eosin (H&E) staining and immunofluorescence were used for the analysis of wound healing. To further explore the mechanism, we performed whole-genome sequencing on extracellular vesicles (EVs). Furthermore, we conducted in vitro experiments. Specifically, exosomes were collected from human umbilical vein endothelial cell (HUVEC) cells after HBO treatment, and then these exosomes were co-incubated with adipose tissue. The wound healing rate in diabetic mice treated with HBO was significantly higher. HBO therapy promotes the proliferation of adipose precursor cells. HUVEC-derived exosomes treated with HBO significantly promoted fat cell browning. These data clarify that HBO therapy may promote vascular endothelial cell proliferation and migration, and promote browning of fat cells through vascular endothelial cells derived exosomes, thereby promoting diabetic wound healing. This provides new ideas for the application of HBO therapy in the treatment of diabetic trauma.