The accumulation of M1-polarized macrophages and excessive inflammation are important in the pathogenesis of diabetic foot ulcer (DFU). However, the underlying mechanism of DFU pathogenesis and the crucial regulators of DFU are less well known. Our previous study reported that kallikrein-binding protein (KBP), an angiogenesis inhibitor, was significantly upregulated in diabetic patients compared to its levels in controls. The effects of KBP on monocyte chemotaxis and macrophage M1 polarization were elucidated in this study. Plasma KBP levels and monocyte counts were assessed by ELISA and flow cytometry. Wound closure rates in different groups were monitored daily. The phenotype and recruitment of macrophages were measured by real-time PCR, western blot and immunofluorescence assays. The expression of Notch and NF-κB signalling pathway members was determined by the methods mentioned above. ChIP and dual-luciferase reporter gene assays were employed to explore the binding and transcriptional regulation of Hes1 and iNOS. We found that plasma KBP levels and circulating monocytes were elevated in diabetic patients compared to those in nondiabetic controls, and both were higher in diabetic patients with DFU than in diabetic patients without DFU. KBP delayed wound healing in normal mice; correspondingly, KBP-neutralizing antibody ameliorated delayed wound healing in diabetic mice. Circulating monocytes and macrophage infiltration in the wound were upregulated in KBP-TG mice compared to those in control mice. KBP promoted the recruitment and M1 polarization of macrophages. Mechanistically, KBP upregulated iNOS by activating the Notch1/RBP-Jκ/Hes1 signalling pathway. Hes1 downregulated CYLD, a negative regulator of NF-κB signalling, and then activated the IKK/IκBα/NF-κB signalling pathway. Our findings demonstrate that KBP is the key regulator of excessive inflammation in DFUs and provide a novel target for DFU therapy.
Bama minipigs are a local pig breed that is unique to China and has a high development and utilization value. However, its high fat content, low feed utilization rate, and slow growth rate have limited its popularity and utilization. Compared with the long breeding cycle and high cost of traditional genetic breeding of pigs, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) endonuclease 9 system (CRISPR/Cas9)-mediated gene editing can cost-effectively implement targeted mutations in animal genomes, thereby providing a powerful tool for rapid improvement of the economic traits of Bama minipigs. The iroquois homeobox 3 (IRX3) gene has been implicated in human obesity. Mouse experiments have shown that knocking out IRX3 significantly enhances basal metabolism, reduces fat content, and controls body mass and composition. This study aimed to knock out IRX3 using the CRISPR/Cas9 gene editing method to breed Bama minipigs with significantly reduced fat content. First, the CRISPR/Cas9 gene editing method was used to efficiently obtain IRX3-/- cells. Then, the gene-edited cells were used as donor cells to produce surviving IRX3-/- Bama minipigs using somatic cell cloning. The results show that the use of IRX3-/- cells as donor cells for the production of somatic cell-cloned pigs results in a significant decrease in the average live litter size and a significant increase in the average number of stillbirths. Moreover, the birth weight of surviving IRX3-/- somatic cell-cloned pigs is significantly lower, and viability is poor such that all piglets die shortly after birth. Therefore, the preliminary results of this study suggest that IRX3 may have important biological functions in pigs, and IRX3 should not be used as a gene editing target to reduce fat content in Bama minipigs. Moreover, this study shows that knocking out IRX3 does not favor the survival of pigs, and whether targeted regulation of IRX3 in the treatment of human obesity will also induce severe adverse consequences requires further investigation.
17 February 2025 in Biochemical and Biophysical Research Communications
Summary: Beige fat dissipates energy and functions as a defense against cold and obesity, but the underlying mechanisms remain unclear. We found that the signaling of interleukin (IL)-25 including its cognate receptor, IL-17 receptor B (IL-17RB), increased in adipose tissue upon cold and β3-adrenoceptor agonist stimulation. IL-25 induced the browning effect in white adipose tissue (WAT) by releasing IL-4, 13 and promoting alternative activation of macrophages to regulate innervation, which characterized as tyrosine hydroxylase (TH) up-regulation to produce more catecholamine including norepinephrine. Blockade of IL-4Rα and depletion of macrophages with clodronate-loaded liposomes in vivo significantly impaired the browning of WAT. Obese mice administered with IL-25 were protected from obesity on a high-fat diet and the subsequent metabolic disorders, and the process involved the uncoupling protein 1 (UCP1)-mediated thermogenesis. In conclusion, the activation of IL-25 signaling on beige fat might play a therapeutic potential for obesity and its associated metabolic disorders.
Background: NK cells play an important role in immune response, immune surveillance, and metabolism regulation. Therefore, NK cells are involved in the occurrence and development of various diseases, such as infectious diseases, cancer, obesity, and diabetes. IL-25 is a special member of the IL-17 family with anti-inflammatory function. IL-25 can regulate inflammatory response and metabolism via various immune cells; however, the role and regulatory mechanism of IL-25 in NK cells are still unclear. Method: In this study, we investigate the role of IL-25 in NK-cell protein profile via 4D label-free mass spectrum and validate the differential proteins via PRM analysis. In addition, GO analysis, KEGG analysis, and other bioinformatic analysis methods are used to explore the enriched function and signal pathway of differentially expressed proteins. Result and Discussion: The GO and KEGG analyses suggest that IL-25 may affect the processes, such as metabolism, thermogenesis, and oxidative phosphorylation of NK cells. There are 7 downregulated proteins (NCR1, GZMB, PRF1, KLRC1, NDUFA11, LAMTOR5, and IKBIP) and 1 up- -regulated protein (PSMD7) in IL-25-treated NK cells versus the control group for PRM validation. Our results indicate that IL-25 may regulate metabolism and other biological processes via NK cells, which will be beneficial in revealing the role and regulatory mechanisms of IL-25 in NK cells in various diseases. Conclusion: Proteomics combined with bioinformatic analysis will help to mine more information hidden behind mass spectrometry data and lay the foundation for finding clinical biomarkers and mechanisms of diseases.
The global obesity epidemic has emerged as a major driver of cancer incidence and mortality, with accumulating evidence highlighting the gut–adipose–tumor axis as a critical mediator of obesity-related carcinogenesis. The gut–adipose–tumor axis is a tripartite communication network, wherein the intestinal microbiome, adipose tissue, and tumor microenvironment engage in dynamic bidirectional crosstalk that alters cancer susceptibility and progression. This review synthesizes current understanding of the epidemiology, pathophysiology, therapeutic implications, and future directions of this axis. Obesity-induced gut dysbiosis leads to systemic dissemination of pro-inflammatory microbial products and metabolites. These gut-derived signals profoundly influence adipose tissue homeostasis, exacerbating chronic low-grade inflammation, promoting macrophage infiltration and polarization, and disrupting adipokine secretion patterns. Dysfunctional adipose tissue generates cancer-promoting mediators and metabolic perturbations. The convergence of gut-derived and adipose-derived signals creates a systemic pro-carcinogenic environment that reshapes the tumor microenvironment through multiple mechanisms. Understanding the gut–adipose–tumor axis as an integrated biological system offers opportunities for cancer prevention and treatment. This is of significant importance for exploring the mechanisms of obesity-related carcinogenesis and developing new therapeutic approaches for obesity-related cancers.