MANF brakes TLR4 signaling by competitively binding S100A8 with S100A9 to regulate macrophage phenotypes in hepatic fibrosis

The mesencephalic astrocyte-derived neurotrophic factor(MANF)has been recently identified as a neurotrophic factor,but its role in hepatic fibrosis is unknown.Here,we found that MANF was upregulated in the fibrotic liver tissues of the patients with chronic liver diseases and of mice treated with CCl4.MANF deficiency in either hepatocytes or hepatic mono-macrophages,particularly in hepatic mono-macrophages,clearly exacerbated hepatic fibrosis.Myeloid-specific MANF knockout increased the population of hepatic Ly6C^(high)macrophages and promoted HSCs activation.Furthermore,MANF-sufficient macrophages(from WT mice)transfusion ameliorated CCl4-induced hepatic fibrosis in myeloid cells-specific MANF knockout(MKO)mice.Mechanistically,MANF interacted with S100A8 to competitively block S100A8/A9 heterodimer formation and inhibited S100A8/A9-mediated TLR4-NF-κB signal activation.Pharmacologically,systemic administration of recombinant human MANF significantly alleviated CCl_(4)-induced hepatic fibrosis in both WT and hepatocytes-specific MANF knockout(HKO)mice.This study reveals a mechanism by which MANF targets S100A8/A9-TLR4 as a“brake”on the upstream of NF-κB pathway,which exerts an impact on macrophage differentiation and shed light on hepatic fibrosis treatment.

SHP2 inhibition triggers anti-tumor immunity and synergizes with PD-1 blockade

Tyrosine phosphatase SHP2 is a promising drug target in cancer immunotherapy due to its bidirectional role in both tumor growth promotion and T-cell inactivation. Its allosteric inhibitor SHP099 is known to inhibit cancer cell growth both in vitro and in vivo. However, whether SHP099-mediated SHP2 inhibition retards tumor growth in vivo via anti-tumor immunity remains elusive. To address this, a CT-26 colon cancer xenograft model was established in mice since this cell line is insensitive to SHP099.Consequently, SHP099 minimally affected CT-26 tumor growth in immuno-deficient nude mice, but significantly decreased the tumor burden in CT-26 tumor-bearing mice with intact immune system.SHP099 augmented anti-tumor immunity, as shown by the elevated proportion of CD8tIFN-γtT cells and the upregulation of cytotoxic T-cell related genes including Granzyme B andPerforin, which decreased the tumor load. In addition, tumor growth in mice with SHP2-deficient T-cells was markedly slowed down because of enhanced anti-tumor responses. Finally, the combination of SHP099 and antiPD-1 antibody showed a higher therapeutic efficacy than either monotherapy in controlling tumor growthin two colon cancer xenograft models, indicating that these agents complement each other. Our study suggests that SHP2 inhibitor SHP099 is a promising candidate drug for cancer immunotherapy.

Allosteric inhibition reveals SHP2-mediated tumor immunosuppression in colon cancer by single-cell transcriptomics

Colorectal cancer(CRC), a malignant tumor worldwide consists of microsatellite instability(MSI) and stable(MSS) phenotypes. Although SHP2 is a hopeful target for cancer therapy, its relationship with innate immunosuppression remains elusive. To address that, single-cell RNA sequencing wasperformed to explore the role of SHP2 in all cell types of tumor microenvironment(TME) from murine MC38 xenografts. Intratumoral cells were found to be functionally heterogeneous and responded significantly to SHP099, a SHP2 allosteric inhibitor. The malignant evolution of tumor cells was remarkably arrested by SHP099. Mechanistically, STING-TBK1-IRF3-mediated type I interferon signaling was highly activated by SHP099 in infiltrated myeloid cells. Notably, CRC patients with MSS phenotype exhibited greater macrophage infiltration and more potent SHP2 phosphorylation in CD68;macrophages than MSI-high phenotypes, suggesting the potential role of macrophagic SHP2 in TME. Collectively,our data reveals a mechanism of innate immunosuppression mediated by SHP2, suggesting that SHP2 is a promising target for colon cancer immunotherapy.

Loss of hnRNP A1 in murine skeletal muscle exacerbates high-fat diet-induced onset of insulin resistance and hepatic steatosis

Impairment of glucose(Glu)uptake and storage by skeletal muscle is a prime risk factor for the development of metabolic diseases.Heterogeneous nuclear ribonucleoprotein A1(hnRNP Al)is a highly abundant RNA-binding protein that has been implicated in diverse cellular functions.The aim of this study was to investigate the function of hnRNP A1 on muscle tissue insulin sensitivity and systemic Glu homeostasis.Our results showed that conditional deletion of hnRNP Al in the muscle gave rise to a severe insulin resistance phenotype in mice fed a high-fat diet(HFD).Conditional knockout mice fed a HFD showed exacerbated obesity,insulin resistance,and hepatic steatosis.In vitro interference of hnRNP Al in C2C12 myotubes impaired insulin signal transduction and inhibited Glu uptake,whereas hnRNP Al overexpression in C2C12 myotubes protected against insulin resistance induced by supraphysiological concentrations of insulin.The expression and stability of glycogen synthase(gysl)mRNA were also decreased in the absence of hnRNP A l.Mechanistically,hnRNP Al interacted with gys l and stabilized its mRNA,thereby promoting glycogen synthesis and maintaining the insulin sensitivity in muscle tissue.Taken together,our findings are the first to show that reduced expression of hnRNP Al in skeletal muscle affects the metabolic properties and systemic insulin sensitivity by inhibiting glycogen synthesis.