Inflachromene inhibits intimal hyperplasia through the HMGB1/2- regulated TLR4-NF-κB pathway

The negative feedback loop of NF-κB/miR-202-5p/HMGB2 attenuates sepsis induced acute kidney injury

Sepsis represents a primary cause of acute kidney injury (AKI), yet the underlying mechanisms of septic AKI remain poorly understood. Thus, there exists an urgent need for a deeper understanding of its underlying mechanisms and the development of effective therapeutic strategies. Our study reveals a notable induction in microRNA-202-5p (miR-202-5p) levels within renal tubular cells in septic AKI both in vivo and in vitro models. Treatment of renal tubular cells with LPS induced NF-κB activation, which was linked to the induction of miR-202-5p. ChIP assays confirmed NF-κB binding to the miR-202-5p gene promoter upon LPS stimulation. Functionally, miR-202-5p mimics attenuated tubular cell death, kidney injury, and intra-renal inflammatory cytokine production, whereas inhibition of miR-202-5p conferred injurious effects in septic AKI. Notably, miR-202-5p suppressed the expression of High Mobility Group Box 2 (HMGB2) in both in vitro and in vivo septic AKI models. Luciferase microRNA target assays further validated HMGB2 as a direct target of miR-202-5p. Knockdown of HMGB2 inhibits LPS-induced NF-κB activation in septic AKI, as evidenced by HMGB2 siRNA transfection significantly inhibited the nuclear translocation of NF-κB. Together, these findings elucidate the NF-κB/miR-202-5p/HMGB2 negative feedback loop which can attenuate kidney injury by inhibiting renal inflammation in septic AKI. Our findings open new avenues for developing targeted therapies to manage septic AKI effectively.

Deficiency of smooth muscle cell ILF3 alleviates intimal hyperplasia via HMGB1 mRNA degradation-mediated regulation of the STAT3/DUSP16 axis

Intimal hyperplasia is a complicated pathophysiological phenomenon attributable to in-stent restenosis, and the underlying mechanism remains unclear. Interleukin enhancer-binding factor 3 (ILF3), a double-stranded RNA-binding protein involved in regulating mRNA stability, has been recently demonstrated to assume a crucial role in cardiovascular disease; nevertheless, its impact on intimal hyperplasia remains unknown. In current study, we used samples of human restenotic arteries and rodent models of intimal hyperplasia, we found that vascular smooth muscle cell (VSMC) ILF3 expression was markedly elevated in human restenotic arteries and murine ligated carotid arteries. SMC-specific ILF3 knockout mice significantly suppressed injury induced neointimal formation. In vitro, platelet-derived growth factor type BB (PDGF-BB) treatment elevated the level of VSMC ILF3 in a dose- and time-dependent manner. ILF3 silencing markedly inhibited PDGF-BB-induced phenotype switching, proliferation, and migration in VSMCs. Transcriptome sequencing and RNA immunoprecipitation sequencing depicted that ILF3 maintained its stability upon binding to the mRNA of the high-mobility group box 1 protein (HMGB1), thereby exerting an inhibitory effect on the transcription of dual specificity phosphatase 16 (DUSP16) through enhanced phosphorylation of signal transducer and activator of transcription 3 (STAT3). Therefore, the results both in vitro and in vivo indicated that the loss of ILF3 in VSMC ameliorated neointimal hyperplasia by regulating the STAT3/DUSP16 axis through the degradation of HMGB1 mRNA. Our findings revealed that vascular injury activates VSMC ILF3, which in turn promotes intima formation. Consequently, targeting specific VSMC ILF3 may present a potential therapeutic strategy for ameliorating cardiovascular restenosis.

A patent review on HMGB1 inhibitors for the treatment of liver diseases

INTRODUCTION

HMGB1 is a non-histone chromatin protein released or secreted in response to tissue damage or infection. Extracellular HMGB1, as a crucial immunomodulatory factor, binds with several different receptors to innate inflammatory responses that aggravate acute and chronic liver diseases. The increased levels of HMGB1 have been reported in various liver diseases, highlighting that it represents a potential biomarker and druggable target for therapeutic development.

AREAS COVERED

This review summarizes the current knowledge on the structure, function, and interacting receptors of HMGB1 and its significance in multiple liver diseases. The latest patented and preclinical studies of HMGB1 inhibitors (antibodies, peptides, and small molecules) for liver diseases are summarized by using the keywords 'HMGB1,' 'HMGB1 antagonist, HMGB1-inhibitor,' 'liver disease' in Web of Science, Google Scholar, Google Patents, and PubMed databases in the year from 2017 to 2023.

EXPERT OPINIONS

In recent years, extensive research on HMGB1-dependent inflammatory signaling has discovered potent inhibitors of HMGB1 to reduce the severity of liver injury. Despite significant progress in the development of HMGB1 antagonists, few of them are approved for clinical treatment of liver-related diseases. Developing safe and effective specific inhibitors for different HMGB1 isoforms and their interaction with receptors is the focus of future research.

High-Mobility Group Box 1 Overexpression Predicts a Poor Prognosis and Promotes Epithelial-Mesenchymal Transition in Gastric Cancer by Activating TLR4/NF-κB Signaling

INTRODUCTION

The molecular mechanism of high-mobility group box 1 (HMGB1) promoting the epithelial-mesenchymal transition (EMT) of gastric cancer (GC) has not been known well. This study aimed to explore the clinical effects of HMGB1 expression levels on the clinicopathological characteristics of patients with GC and to uncover the potential molecular mechanism which promotes tumor progression.

METHODS

The expression levels of HMGB1 in 125 patients with GC were detected by immunohistochemistry and Western blotting. Univariate and multivariate analyses were performed to evaluate the relationship between HMGB1 expression and clinical characteristics of patients with GC. Stable overexpression (over-HMGB1) and knockdown (sh-HMGB1) GC cell lines (AGS and MKN-45) were used to determine the effects of HMGB1 on the activation of TLR4/NF-κB signaling. Differences were considered statistically significant at p < 0.05 in two sides.

RESULTS

HMGB1 is highly expressed in GC tissues and cell lines. High HMGB1 expression (HR = 1.89, 95% CI: 1.44-2.39, p = 0.001) was an independent risk factor for overall survival in patients with GC. Downregulation of HMGB1 resulted in downregulation of TLR4 and NF-κB subunit (p-p65 and p-IκBα) expression, whereas the upregulated expression of HMGB1 led to increased expression of TLR4 and NF-κB subunits. Overexpression of HMGB1 promotes the upregulation of EMT-TF expression, which enhances the proliferation and migration abilities of GC cell lines.

CONCLUSION

HMGB1 is highly expressed in GC tissues and is associated with a poorer prognosis in patients with GC. HMGB1 activates the TLR4/NF-κB signaling pathway to promote EMT progression in GC cell lines. HMGB1 may be a critical molecule in prognosis prediction and a therapeutic target for patients with GC.

HMGB family proteins: Potential biomarkers and mechanistic factors in cardiovascular diseases

Cardiovascular disease (CVD) is the most fatal disease that causes sudden death, and inflammation contributes substantially to its occurrence and progression. The prevalence of CVD increases as the population ages, and the pathophysiology is complex. Anti-inflammatory and immunological modulation are the potential methods for CVD prevention and treatment. High-Mobility Group (HMG) chromosomal proteins are one of the most abundant nuclear nonhistone proteins which act as inflammatory mediators in DNA replication, transcription, and repair by producing cytokines and serving as damage-associated molecular patterns in inflammatory responses. The most common and well-studied HMG proteins are those with an HMGB domain, which participate in a variety of biological processes. HMGB1 and HMGB2 were the first members of the HMGB family to be identified and are present in all investigated eukaryotes. Our review is primarily concerned with the involvement of HMGB1 and HMGB2 in CVD. The purpose of this review is to provide a theoretical framework for diagnosing and treating CVD by discussing the structure and function of HMGB1 and HMGB2.