Single-Cell Sequencing Reveals MYOF-Enriched Monocyte/Macrophage Subcluster as a Favorable Prognostic Factor in Sepsis.

This research utilized single-cell RNA sequencing to map the immune cell landscape in sepsis, revealing 28 distinct cell clusters and categorizing them into nine major types. Delving into the monocyte/macrophage subclusters, 12 unique subclusters are identified and pathway enrichment analyses are conducted using KEGG and GO, discovering enriched pathways such as oxidative phosphorylation and antigen processing. Further GSVA and AUCell assessments show varied activation of interferon pathways, especially in subclusters 4 and 11. The clinical correlation analysis reveals genes significantly linked to survival outcomes. Additionally, cellular differentiation in these subclusters is explored. Building on these insights, the differential gene expression within these subclusters is specifically scrutinized, which reveal MYOF as a key gene with elevated expression levels in the survivor group. This finding is further supported by in-depth pathway enrichment analysis and the examination of cellular differentiation trajectories, where MYOF's role became evident in the context of immune response regulation and sepsis progression. Validating the role of the MYOF gene in sepsis, a dose-dependent response to LPS in THP-1 cells and C57 mice is observed. Finally, inter-cellular communications are analyzed, particularly focusing on the MYOF+Mono/Macro subcluster, which indicates a pivotal role in immune regulation and potential therapeutic targeting.

c-Myb Dominates TBK1-Mediated Endotoxin Tolerance in Kupffer Cells by Negatively Regulating DTX4.

As a protective mechanism regulating excessive inflammation, endotoxin tolerance plays a vital role in regulating endotoxin shock. Kupffer cells are players in mediating endotoxin tolerance. Nonetheless, the regulatory mechanism regulating endotoxin tolerance is barely known. A nonclassical IKK kinase called TRAF-associated NF-κB activator (TANK)-binding kinase 1 (TBK1) can regulate inflammation. Here, we found that TBK1 is required for endotoxin tolerance in Kupffer cells. TBK1 plays a dominant role in regulating endotoxin tolerance by negatively regulating the induction of p100 processing. Deltex E3 ubiquitin ligase 4 (DTX4), a negative regulator of TBK1, can promote TBK1 K48-mediated ubiquitination and indirectly regulate endotoxin tolerance in Kupffer cells. We demonstrate that the c-Myb transcription factor could negatively regulate DTX4. Overexpression of c-Myb can be used to reduce the ubiquitination of TBK1 by reducing DTX4 transcription and to boost the anti-inflammatory effect of endotoxin tolerance. Thus, this study reveals a novel theory of TBK1-mediated endotoxin tolerance in Kupffer cells.

Total Antioxidant Capacity and Pancreatic Cancer Incidence and Mortality in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial.

BACKGROUND: Total antioxidant capacity (TAC) reflects an individual's overall antioxidant intake. We sought to clarify whether higher TAC is associated with lower risks of pancreatic cancer incidence and mortality in the U.S. general population. METHODS: A total of 96,018 American adults were identified from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. A ferric-reducing ability of plasma score was used to reflect an individual's TAC intake from diet and/or supplements. Cox regression was used to calculate hazard ratios (HR) for pancreatic cancer incidence, and competing risk regression was used to calculate subdistribution HRs for pancreatic cancer mortality. Restricted cubic spline regression was used to test nonlinearity. RESULTS: A total of 393 pancreatic cancer cases and 353 pancreatic cancer-related deaths were documented. Total (diet + supplements) TAC was found to be inversely associated with pancreatic cancer incidence (HR quartile 4 vs. quartile 1 = 0.53; 95% confidence interval, 0.39-0.72; P trend = 0.0002) and mortality (subdistribution HR quartile 4 vs. quartile 1 = 0.52; 95% confidence interval 0.38-0.72; P trend = 0.0003) in a nonlinear dose-response manner (all P nonlinearity < 0.01). Similar results were observed for dietary TAC. No association of supplemental TAC with pancreatic cancer incidence and mortality was found. CONCLUSIONS: In the U.S. general population, dietary but not supplemental TAC level is inversely associated with risks of pancreatic cancer incidence and mortality in a nonlinear dose-response pattern. IMPACT: This is the first prospective study indicating that a diet rich in antioxidants may be beneficial in decreasing pancreatic cancer incidence and mortality.

Transcriptional co-regulator RIP140: An important mediator of the inflammatory response and its associated diseases (Review).

The inflammatory response is a physiological process that is essential for maintaining homeostasis of the immune system. Inflammation is classified into acute inflammation and chronic inflammation, both of which pose a risk to human health. However, specific regulatory mechanisms of the inflammatory response remain to be elucidated. Receptor interacting protein (RIP) 140 is a nuclear receptor that affects an extensive array of biological and pathological processes in the body, including energy metabolism, inflammation and tumorigenesis. RIP140­mediated macrophage polarization is important in regulating the inflammatory response. Overexpression of RIP140 in macrophages results in M1­like polarization and expansion during the inflammatory response. Conversely, decreased expression of RIP140 in macrophages reduces the number of M1­like macrophages and increases the number of alternatively polarized cells, which collectively promote endotoxin tolerance (ET) and relieve inflammation. This review summarizes the role of RIP140 in acute and chronic inflammatory diseases, with a focus on insulin resistance, atherosclerosis, sepsis and ET.

Overexpression of RIP140 suppresses the malignant potential of hepatocellular carcinoma by inhibiting NF­κB­mediated alternative polarization of macrophages.

Tumor-associated macrophages (TAMs) and their alternative activation contribute greatly to the development of hepatocellular carcinoma (HCC). Receptor-interacting protein 140 (RIP140) is widely expressed in macrophages and regulates macrophage-mediated energy metabolism, the inflammatory response and tumorigenesis. However, whether RIP140 is involved in the activation of TAMs has not been reported. In the present study, we determined the expression of RIP140 in macrophages after treatment with HCC-conditioned medium (HCM) for 24 h. We also analyzed the effects of RIP140 overexpression on macrophage polarization, invasion and apoptosis of HepG2 and Huh7 cells. Transwell and apoptosis assays were used to estimated cell invasion and apoptosis. In addition, we investigated the effects of RIP140 overexpression in macrophages on the growth of H22 cells by subcutaneous injection of H22 cells along with macrophages in BALB/c nude mice. Western blotting and qRT-PCR were used to detect protein and mRNA expression associated with the NF-κB/IL-6 axis in TAMs. Immunohistochemical and immunofluorescence staining were used to evaluate the protein expression of RIP140 or F4/80 in human HCC samples. The protein expression of RIP140 in peripheral blood mononuclear cells was detected by western blotting. Kaplan­Meier survival curve estimation of overall survival for patients with HCC was based on RIP140 or F4/80 expression in HCC samples. We found that HCM inhibited RIP140 expression and fostered the alternative activation of macrophages. RIP140 overexpression in TAMs significantly inhibited the alternative activation of macrophages by inhibiting the NF-κB/IL-6 axis in TAMs, and suppressed HCC cell growth both in vitro and in vivo. In addition, the protein expression of RIP140 in peripheral blood monocytes was significantly lower in patients with HCC than in healthy people, and this result was consistent with the expression of RIP140 in HCC samples. Furthermore, low RIP140 expression and high F4/80 expression were found to be closely correlated with shorter survival time of the patients with HCC.

[Over-expression of receptor-interacting protein 140 in tumor-associated macrophages suppresses invasion and proliferation of hepatoma cells in vitro].

OBJECTIVE: To investigate the role of receptor-interacting protein 140 (RIP140) in tumor-associated macrophages (TAMs) in the invasion and proliferation of hepatoma cells in vitro. METHODS: Western blotting, qRT-PCR and flow cytometry were performed to examine the effects of lentivirus-mediated RIP140 over-expression in mouse peritoneal macrophages (PMs). Western blotting, qRT-PCR and immunofluorescence staining were used to detect the expression of RIP140 in TAMs following stimulation of the PMs with hepatocellular carcinoma conditioned medium (HCM) for 24 h. The polarization index and the expression of NF-κB and IL-6 were detected using qRT-PCR in TAMs in HCM-stimulated PMs with or without RIP140 over-expression. Transwell assay and flow cytometry were used to estimate the cell invasion and apoptosis. HE staining and immunohistochemical staining were used to analyze the effects of RIP140-over-expressing macrophages on the growth and tumor formation of H22 cells in BALB/c nude mice. RESULTS: The lentivirus vector efficiently mediated RIP140 over-expression in mouse PMs. HCM stimulation significantly inhibited RIP140 expression in the TAMs and promoted their M2-like polarization. Over-expression of RIP140 in PMs suppressed the invasion and induced apoptosis of HCC cells. RIP140 over-expression inhibited HCM-induced M2 polarization and the activation of NF-κB/IL-6 axis in the TAMs, and RIP140- overexpressing TAMs obviously suppressed the growth of H22 cell xenograft in nude mice. CONCLUSION: Over-expression of RIP140 in TAMs suppresses the growth and proliferation of hepatoma cells possibly by inhibiting M2 polarization of the TAMs.