Visualising pattern recognition receptor signalling

Therapeutic landscape in systemic lupus erythematosus: mtDNA activation of the cGAS-STING pathway

Mitochondrial DNA (mtDNA) serves as a pivotal immune stimulus in the immune response. During stress, mitochondria release mtDNA into the cytoplasm, where it is recognized by the cytoplasmic DNA receptor cGAS. This activation initiates the cGAS-STING-IRF3 pathway, culminating in an inflammatory response. The cGAS-STING pathway has emerged as a critical mediator of inflammatory responses in microbial infections, stress, autoimmune diseases, chronic illnesses, and tissue injuries. Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by connective tissue involvement across various bodily systems. Its hallmark is the production of numerous autoantibodies, which prompt the immune system to target and damage the body's own tissues, resulting in organ and tissue damage. Increasing evidence implicates the cGAS-STING pathway as a significant contributor to SLE pathogenesis. This article aims to explore the role of the mtDNA-triggered cGAS-STING pathway and its mechanisms in SLE, with the goal of providing novel insights for clinical interventions.

What type of cell death occurs in chronic cerebral hypoperfusion? A review focusing on pyroptosis and its potential therapeutic implications

Chronic cerebral hypoperfusion (CCH) is a major global disease with chronic cerebral blood flow reduction. It is also the main cause of cognitive impairment and neurodegenerative diseases. Pyroptosis, a novel form of cell death, is characterized by the rupture of the cell membrane and the release of pro-inflammatory mediators. In recent years, an increasing number of studies have identified the involvement of pyroptosis and its mediated inflammatory response in the pathological process of CCH. Therefore, preventing the activation of pyroptosis following CCH is beneficial to inhibit the inflammatory cascade and reduce brain injury. In this review, we discuss the research progress on the relationship between pyroptosis and CCH, in order to provide a reference for research in related fields.

Inflammasome and Its Therapeutic Targeting in Rheumatoid Arthritis

Inflammasome is a cytoplasmic multiprotein complex that facilitates the clearance of exogenous microorganisms or the recognition of endogenous danger signals, which is critically involved in innate inflammatory response. Excessive or abnormal activation of inflammasomes has been shown to contribute to the development of various diseases including autoimmune diseases, neurodegenerative changes, and cancers. Rheumatoid arthritis (RA) is a chronic and complex autoimmune disease, in which inflammasome activation plays a pivotal role in immune dysregulation and joint inflammation. This review summarizes recent findings on inflammasome activation and its effector mechanisms in the pathogenesis of RA and potential development of therapeutic targeting of inflammasome for the immunotherapy of RA.

NOD-like receptors in autoimmune diseases

Autoimmune diseases are chronic immune diseases characterized by dysregulation of immune system, which ultimately results in a disruption in self-antigen tolerance. Cumulative data show that nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) play essential roles in various autoimmune diseases, such as inflammatory bowel disease (IBD), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), psoriasis, multiple sclerosis (MS), etc. NLR proteins, consisting of a C-terminal leucine-rich repeat (LRR), a central nucleotide-binding domain, and an N-terminal effector domain, form a group of pattern recognition receptors (PRRs) that mediate the immune response by specifically recognizing cellular pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs) and triggering numerous signaling pathways, including RIP2 kinase, caspase-1, nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK) and so on. Based on their N-terminal domain, NLRs are divided into five subfamilies: NLRA, NLRB, NLRC, NLRP, and NLRX1. In this review, we briefly describe the structures and signaling pathways of NLRs, summarize the recent progress on NLR signaling in the occurrence and development of autoimmune diseases, as well as highlight numerous natural products and synthetic compounds targeting NLRs for the treatment of autoimmune diseases.

Molecular Markers of MDR of Chemotherapy for HSCC: Proteomic Screening With High-Throughput Liquid Chromatography-Tandem Mass Spectrometry

Background

Hypopharyngeal squamous cell cancer (HSCC) is a head and neck tumor with a poor prognosis. Chemotherapy lacks effectiveness because of multidrug resistance (MDR), which has increased toxic side effects. Thus, there is an urgent need to identify the molecular markers of MDR of chemotherapy for HSCC.

Methods

Fifty clinical samples of HSCC were derived from patients including 12 sensitive or resistant to chemotherapy drugs. Proteomic screening was performed using liquid chromatography-tandem mass spectrometry (LC-MS), which was based on data-independent acquisition. Molecular markers of MDR of chemotherapy in patients with HSCC were identified with clinical data and validated with ELISA.

Results

A total of 673 differentially expressed proteins were identified in HSCC samples, where 172 were upregulated and 501 were downregulated. A total of 183 differentially expressed proteins including 102 upregulated and 81 downregulated proteins, were identified by comparing cancer sensitive to chemotherapy with cancer resistant to chemotherapy. Clinical HSCC samples had significantly higher expression of FADD and significantly lower expression of RIPK1. Expressions of FADD and RIPK1 proteins were significantly lower in the chemotherapy-sensitive group. These expression differences were not correlated with clinical data. RIPK1 and FADD are involved in necroptosis and the signaling pathway of PRRs. Using ELISA, the low expression of RIPK1 and FADD was found in the patients sensitive to chemotherapy.

Conclusion

LC-MS proteomics is an effective method to identify the molecular markers of HSCC. FADD and RIPK1 can act as molecular markers of MDR of chemotherapy in patients with HSCC and may function through necroptosis and the PRR signaling pathway.

Driver Gene Mutations and Epigenetics in Colorectal Cancer

OBJECTIVE

The majority of patients with colorectal cancer are diagnosed with locally advanced and/or disseminated disease, and treatment options include surgery in combination with cytotoxic chemotherapy regimens, biologics, and/or radiotherapy. Thus, colorectal cancer remains a heavy burden on society and health care systems.Mounting evidence show that driver gene mutations play only part of the role in carcinogenesis. Epigenetics are strongly implicated in initiation and progression of colorectal cancer along with major players such as intestinal microbiotic dysbiosis and chronic mucosal inflammation.To assess phenotypic changes in proteins and gene expression, multigene expression signatures based on sequencing techniques have been developed to hopefully improve predictors of the tumor profile, immune response, and therapeutic outcomes. Our objective was to review current advances in the field and to update surgeons and academics on driver gene mutations and epigenetics in colorectal cancer.

BACKGROUND AND METHODS

This is a narrative review studying relevant research published in the PUBMED database from 2012-2018.

RESULTS AND CONCLUSION

Increased understanding of the molecular biology will improve options to characterize colorectal cancer with regard to mutations and molecular pathways, including microsatellite instability, epigenetics, microbiota, and microenvironment. Research will inevitably improve risk group stratification and targeted treatment approaches.Epigenetic profiling and epigenetic modulating drugs will increase risk stratification, increase accessibility for DNA targeting chemotherapeutics and reduce cytotoxic drug resistance.New generation antibiotics such as biofilm inhibitors and quorum sensing inhibitors are being developed to target the carcinogenetic impact of colonic dysbiosis and inflammation.

Secoeudesma sesquiterpenes lactone A alleviates inflammation and offers adjuvant protection in severe infection of carbapenem-resistant Klebsiella pneumoniae

ETHNOPHARMACOLOGICAL RELEVANCE

Secoeudesma sesquiterpenes lactone A (SESLA) is a sesquiterpene compound isolated from Inula japonica Thunb. (I. japonica). It is an herb widely distributed in Asian countries often used for the treatment of various conditions including tumors, bronchitis and bacterial and viral infections. It has been reported that SESLA could significantly inhibit the production of nitric oxide (NO) by lipopolysaccharide (LPS) in Raw264.7 cells. However, the mechanism responsible for this anti-inflammatory role and its role in the treatment of antibiotic-resistant bacterial infection, e.g., carbapenem-resistant Klebsiella pneumoniae (CRKP), remain to be investigated.

AIM OF THE STUDY

This study was carried out to investigate the protective anti-inflammatory role and the underlying molecular mechanisms of SESLA in LPS or CRKP evoked inflammation.

MATERIALS AND METHODS

ELISA and PCR were utilized to detect the expression of inflammatory mediators in LPS or heat-killed CRKP (HK CRKP)-stimulated immune cells containing different concentrations of SESLA. The protective role of SESLA was observed in mice challenged with a lethal dose of CRKP. Mice were intraperitoneally injected with CRKP to create a septic mouse model to evaluate the protective role of SESLA in vivo. Phosphorylated proteins, which represented the activation of signaling pathways, were examined by Western blot.

RESULTS

SESLA was showed to inhibit the expression of inflammatory mediators in various macrophages and dendritic cells upon stimulation of LPS or HK CRKP. It also facilitated phagocytosis of bacteria by Raw264.7 cells. The combined use of SELSA and the ineffective antibiotic, meropenem, increased the survival rate of CRKP infected mice from 25% to 50%. ERK, NF-κB and PI3K/Akt pathways accounted for the anti-inflammatory role of SESLA with the stimulation of LPS.

CONCLUSION

According to the notable anti-inflammatory effect in vitro and its joint protective effects on a septic mouse model, SESLA might act as an adjuvant drug candidate for sepsis, even those caused by antibiotic-resistant bacteria, e.g., CRKP.

The role of gut microbiota in non-alcoholic fatty liver disease: pathways of mechanisms

Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. Its prevalence increases with increasing rates of obesity, insulin resistance, and diabetes mellitus. The pathogenesis of NAFLD involves many factors, including the gastrointestinal microbiota. However, there is still debate about the impact of gut dysbiosis in the NAFLD disease progression. Therefore, this paper aims to review the relationship between gut microbiota and other risk factors for NAFLD and how gut dysbiosis plays a role in the pathogenesis of NAFLD. Hopefully, this paper can make an appropriate contribution to the development of NAFLD research in the future.

Molecular characterization and expression analysis of TLR1 and TLR4 from the endangered fish Dabry's sturgeon (Acipenser dabryanus)

Toll-like receptors (TLRs) are important pattern recognition receptors (PRRs) of teleost innate immune system. However, information about TLRs is absent in Dabry's sturgeon (Acipenser dabryanus), one of the most primitive actinopterygii species. In the present study, the full lengths of adaTLR1 and adaTLR4 were cloned from Dabry's sturgeon using RT-PCR and RACE-PCR. The obtained adaTLR1 was 2957 bp in length, encoding a putative protein of 767 amino acids and adaTLR4 cDNA was 2902 bp in length, encoding a putative protein of 830 aa. Both adaTLR1 and adaTLR4 possessed several typical TLRs motifs, including signal peptides, leucine-rich repeat (LRR) motifs, a transmembrane domain and a TIR motifs. In addition, adaTLR4 contained three conserved boxes in its TIR motif, involving in TLRs signal transduction. A proline, important for LPS recognition of mammalian TLR4, was also found in adaTLR4. Physicochemical features of adaTLR1 and adaTRL4 were also analyzed. Quantitative realtime PCR showed that both transcripts were ubiquitously expressed in all 11 normal tissues selected, but they exhibited different expression patterns, with adaTLR1 highly expression in heart and adaTLR4 highly in skin. Further, adaTLR1 and adaTLR4 were up-regulated in the primary head-kidney leucocytes following LPS and polyI:C stimulation, indicating that both genes involved in the sturgeon immune response to LPS and polyI:C. To our best knowledge, this was the first report of these genes in sturgeon and these results provided the basis for further elucidating the ligand specificity and signaling pathway of fish TLRs.