The immunomodulatory effects of probiotics and azithromycin in dextran sodium sulfate-induced ulcerative colitis in rats via TLR4-NF-κB and p38-MAPK pathway

Effect of mesenchymal stem cells and melatonin on experimentally induced peripheral nerve injury in rats

Injury of a peripheral nerve (PNI) leads to both ischemic and inflammatory alterations. Sciatic nerve injury (SNI) represents the most widely used model for PNI. Mesenchymal stem cell-based therapy (MSCs) has convenient properties on PNI by stimulating the nerve regeneration. Melatonin has cytoprotective activity. The neuroprotective characteristics of MSCs and melatonin separately or in combination remain a knowledge need. In the rats-challenged SNI, therapeutic roles of intralesional MSCs and intraperitoneal melatonin injections were evaluated by functional assessment of peripheral nerve regeneration by walking track analysis involving sciatic function index (SFI) and two electrophysiological tests, electromyography and nerve conduction velocity, as well as measurement of antioxidant markers in serum, total antioxidant capacity (TAC) and malondialdehyde, and mRNA expression of brain derived neurotrophic factor (BDNF) in nerve tissues in addition to the histopathological evaluation of nerve tissue. Both individual and combination therapy with MSCs and melatonin therapies could effectively ameliorate this SNI and promote its regeneration as evidenced by improving the SFI and two electrophysiological tests and remarkable elevation of TAC with decline in lipid peroxidation and upregulation of BDNF levels. All of these led to functional improvement of the damaged nerve tissues and good recovery of the histopathological sections of sciatic nerve tissues suggesting multifactorial synergistic approach of the concurrent usage of melatonin and MSCs in PNI. The combination regimen has the most synergistic neuro-beneficial effects in PNI that should be used as therapeutic option in patients with PNI to boost their quality of life.

Ferroptosis in ulcerative colitis: Potential mechanisms and promising therapeutic targets

Ulcerative colitis (UC) is a complex immune-mediated chronic inflammatory bowel disease. It is mainly characterized by diffuse inflammation of the colonic and rectal mucosa with barrier function impairment. Identifying new biomarkers for the development of more effective UC therapies remains a pressing task for current research. Ferroptosis is a newly identified form of regulated cell death characterized by iron-dependent lipid peroxidation. As research deepens, ferroptosis has been demonstrated to be involved in the pathological processes of numerous diseases. A growing body of evidence suggests that the pathogenesis of UC is associated with ferroptosis, and the regulation of ferroptosis provides new opportunities for UC treatment. However, the specific mechanisms by which ferroptosis participates in the development of UC remain to be more fully and thoroughly investigated. Therefore, in this review, we focus on the research advances in the mechanism of ferroptosis in recent years and describe the potential role of ferroptosis in the pathogenesis of UC. In addition, we explore the underlying role of the crosslinked pathway between ferroptosis and other mechanisms such as macrophages, neutrophils, autophagy, endoplasmic reticulum stress, and gut microbiota in UC. Finally, we also summarize the potential compounds that may act as ferroptosis inhibitors in UC in the future.

Discovery of 6-Acylamino/Sulfonamido Benzoxazolone with IL-6 Inhibitory Activity as Promising Therapeutic Agents for Ulcerative Colitis

Ulcerative colitis has been widely concerned for its persistent upward trend, and the sustained overproduction of pro-inflammatory cytokines such as IL-6 remains a crucial factor in the development of UC. Therefore, the identification of new effective drugs to block inflammatory responses is an urgent and viable therapeutic strategy for UC. In our research, twenty-three 6-acylamino/sulfonamido benzoxazolone derivatives were synthesized, characterized, and evaluated for anti-inflammatory activity against NO and IL-6 production in LPS-induced RAW264.7 cells. The results demonstrated that most of the target compounds were capable of reducing the overexpression of NO and IL-6 to a certain degree. For the most active compounds 3i, 3j and 3 l, the inhibitory activities were superior or equivalent to those of the positive drug celecoxib with a dose-dependent relationship. Furthermore, animal experiments revealed that active derivatives 3i, 3j and 3 l exhibited definitive therapeutical effect on DSS induced ulcerative colitis in mice by mitigating weight loss and DAI score while decreasing levels of pro-inflammatory cytokines such as IL-6 and IFN-γ, simultaneously increasing production of anti-inflammatory cytokines IL-10. In addition, compounds 3i, 3j and 3 l could also inhibit the oxidative stress to alleviate ulcerative colitis by decreasing MDA and MPO levels. These finding demonstrated that compounds 3i, 3j and 3 l hold significant potential as novel therapeutic agents for ulcerative colitis.

Protective effects of functional Nano-Selenium supplementation on spleen injury through regulation of p38 MAPK and NF-κB protein expression

Selenium (Se) is a trace element necessary for humans to maintain normal physiological activities, and Se deficiency may lead to splenic injury, while Se supplementation can alleviate splenic injury. However, the mechanism is unclear. In this study, we constructed a Se deficiency animal model by feeding Sprague-Dawley (SD) rats with low Se feed. Meanwhile, we observed the repairing effect of Se supplementation on splenic injury with two doses of novel nano-selenium (Nano-Se) supplement by gavage. We measured the Se content in the spleens of the rats by atomic fluorescence spectroscopy (AFS) method and combined the results of hematoxylin-eosin (HE) and Masson staining to observe the splenic injury, comprehensively evaluating the construction of the animal model of low selenium-induced splenic injury. We measured the mRNA and protein expression levels of p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor kappa-B (NF-κB), and interleukin-6 (IL-6) in the spleen by Real-time quantitative polymerase chain reaction (qPCR), western blot (WB), and immunohistochemistry (IHC). We found that the Se deficiency group exhibited lower Se content, splenic fibrosis, and high expression of p38 MAPK, NF-κB, and IL-6 compared to the normal group. The Se supplement groups exhibited higher Se content, attenuated splenic injury, and down-regulated expression of p38 MAPK, NF-κB, and IL-6 relative to the Se deficiency group. This study suggests that Se deficiency leads to splenic injury in rats, and Se supplementation may attenuate splenic injury by inhibiting the expression of p38 MAPK, NF-κB and IL-6.

Wuling capsule modulates macrophage polarization by inhibiting the TLR4-NF-κB signaling pathway to relieve liver fibrosis

BACKGROUND AND PURPOSE

Wuling capsule (WL) has good efficacy in the clinical treatment of chronic hepatitis B and liver injury. Liver fibrosis is a common pathological feature of chronic liver disease and may progress to irreversible cirrhosis and liver cancer. Accumulating evidence reveals that modulating macrophage polarization contribute to the therapy of liver fibrosis. However, the effects of WL on modulating macrophage polarization to relive liver fibrosis remain unclear. This study investigated the anti-liver fibrosis effects of WL in carbon tetrachloride (CCl4)-induced liver fibrosis in rats, and the modulation effects and underlying molecular mechanism on macrophage polarization.

METHODS

A rat liver fibrosis model was constructed by intraperitoneal injection of 40 % CCl4 olive oil mixture. At 2, 4, 6, and 8 weeks, the histopathological status of the liver was assessed by hematoxylin-eosin (HE) and Masson staining; the liver biochemical indexes were measured in rat liver tissue. The expression levels of inflammatory cytokines in liver tissue were detected by ELISA. The mRNA levels and proteins expression of macrophage markers of different phenotypes, TLR4-NF-κB signaling pathway indicators were detected independently by ELISA, immunofluorescence, RT-PCR and western blotting.

RESULTS

In vivo, WL treatment attenuated abnormal changes in weight, organ indices and biochemical indices, alleviated pathological changes, and reduced collagen fiber deposition as well as the expression of α-SMA in liver tissues. Further studies revealed that WL decreased the expression of the macrophage M1 polarization markers inducible nitric oxide synthase (iNOS), TNF-α, IL-6, and CD86, promoted the expression of the M2 macrophage polarization markers IL-10, CD206, and arginase-1 (Arg-1), and inhibited the activation of the TLR4-NF-κB signaling pathway via several key signaling proteins. In vitro, WL significantly suppressed macrophage M1 polarization, and promoted M2 polarization while boosted M1 polarization transform to M2 polarization in LPS-activated RAW264.7 cells.

CONCLUSIONS

This study demonstrated that WL modulated macrophage polarization against liver fibrosis mainly by inhibiting the activation of the TLR4-NF-κB signaling pathway.

Arabinose confers protection against intestinal injury by improving integrity of intestinal mucosal barrier

There is a growing amount of research that highlights the significant involvement of metabolic imbalance and the inflammatory response in the advancement of colitis. Arabinose is a naturally occurring bioactive monosaccharide that plays a crucial role in the metabolic processes and synthesis of many compounds in living organisms. However, the more detailed molecular mechanism by which the administration of arabinose alleviates the progression of colitis and its associated carcinogenesis is still not fully understood. In the present study, arabinose is recognized as a significant and inherent protector of the intestinal mucosal barrier through its role in preserving the integrity of tight junctions within the intestines. Also, it is important to note that there is a positive correlation between the severity of inflammatory bowel disease (IBD) and colorectal cancer (CRC), as well as chemically-induced colitis in mice, and lower levels of arabinose in the bloodstream. In two mouse models of colitis, caused by dextran sodium sulfate (DSS) or by spontaneous colitis in IL-10-/- mice, damage to the intestinal mucosa was reduced by giving the mice arabinose. When arabinose is administrated to model with colitis, it sets off a chain of events that help keep the lysosomes together and stop cathepsin B from being released. During the progression of intestinal epithelial injury, this process blocks myosin light chain kinase (MLCK) from damaging tight junctions and causing mitochondrial dysfunction. In summary, the results of the study have provided evidence supporting the beneficial effects of arabinose in mitigating the progression of colitis. This is achieved through its ability to avoid dysregulation of the intestinal barrier. Consequently, arabinose may hold promise as a therapeutic supplementation for the management of colitis.

Complete genome analysis of Bacillus velezensis TS5 and its potential as a probiotic strain in mice

Introduction

In recent years, a large number of studies have shown that Bacillus velezensis has the potential as an animal feed additive, and its potential probiotic properties have been gradually explored.

Methods

In this study, Illumina NovaSeq PE150 and Oxford Nanopore ONT sequencing platforms were used to sequence the genome of Bacillus velezensis TS5, a fiber-degrading strain isolated from Tibetan sheep. To further investigate the potential of B. velezensis TS5 as a probiotic strain, in vivo experiments were conducted using 40 five-week-old male specific pathogen-free C57BL/6J mice. The mice were randomly divided into four groups: high fiber diet control group (H group), high fiber diet probiotics group (HT group), low fiber diet control group (L group), and low fiber diet probiotics group (LT group). The H and HT groups were fed high-fiber diet (30%), while the L and LT groups were fed low-fiber diet (5%). The total bacteria amount in the vegetative forms of B. velezensis TS5 per mouse in the HT and LT groups was 1 × 109 CFU per day, mice in the H and L groups were given the same volume of sterile physiological saline daily by gavage, and the experiment period lasted for 8 weeks.

Results

The complete genome sequencing results of B. velezensis TS5 showed that it contained 3,929,788 nucleotides with a GC content of 46.50%. The strain encoded 3,873 genes that partially related to stress resistance, adhesion, and antioxidants, as well as the production of secondary metabolites, digestive enzymes, and other beneficial nutrients. The genes of this bacterium were mainly involved in carbohydrate metabolism, amino acid metabolism, vitamin and cofactor metabolism, biological process, and molecular function, as revealed by KEGG and GO databases. The results of mouse tests showed that B. velezensis TS5 could improve intestinal digestive enzyme activity, liver antioxidant capacity, small intestine morphology, and cecum microbiota structure in mice.

Conclusion

These findings confirmed the probiotic effects of B. velezensis TS5 isolated from Tibetan sheep feces and provided the theoretical basis for the clinical application and development of new feed additives.

Stattic ameliorates the cecal ligation and puncture-induced cardiac injury in septic mice via IL-6-gp130-STAT3 signaling pathway

AIM

Sepsis-induced cardiac dysfunction is the leading cause of higher morbidity and mortality with poor prognosis in septic patients. Our recent previous investigation provides evidence of the hallmarks of signal transducer and activator of transcription3 (STAT3) activation in sepsis and targeting of STAT3 with Stattic, a small-molecule inhibitor of STAT3, has beneficial effects in various septic tissues. We investigated the possible cardioprotective effects of Stattic on cardiac inflammation and dysfunction in mice with cecal ligation and puncture (CLP)-induced sepsis.

MAIN METHODS

A polymicrobial sepsis model was induced by CLP in mice and Stattic (25 mg/kg) was intraperitoneally given at one and twelve hours after CLP operation. The cecum was exposed in sham-control mice without CLP. After 18 h of surgery, electrocardiogram (ECG) for anaesthized mice was registered followed by collecting of samples of blood and tissues for bimolecular and histopathological assessments. Myeloperoxidase, a marker of neutrophil infiltration, was assessed immunohistochemically.

KEY FINDINGS

CLP profoundly impaired cardiac functions as evidenced by ECG changes in septic mice as well as elevation of cardiac enzymes, and inflammatory markers with myocardial histopathological and immunohistochemical alterations. While, Stattic markedly reversed the CLP-induced cardiac abnormalities and restored the cardiac function by its anti-inflammatory activities.

SIGNIFICANCE

Stattic treatment had potential beneficial effects against sepsis-induced cardiac inflammation, dysfunction and damage. Its cardioprotective effects were possibly attributed to its anti-inflammatory activities by targeting STAT3 and downregulation of IL-6 and gp130. Our investigations suggest that Stattic could be a promising target for management of cardiac sepsis and inflammation-related cardiac damage.

Fecal microbiota transplantation alleviates experimental colitis through the Toll-like receptor 4 signaling pathway

BACKGROUND

Fecal microbiota transplantation (FMT) has shown promising therapeutic effects on mice with experimental colitis and patients with ulcerative colitis (UC). FMT modulates the Toll-like receptor 4 (TLR4) signaling pathway to treat some other diseases. However, it remains unknown whether this modulation is also involved in the treatment of UC.

AIM

To clarify the necessity of TLR4 signaling pathway in FMT on dextran sodium sulphate (DSS)-induced mice and explain the mechanism of FMT on UC, through association analysis of gut microbiota with colon transcriptome in mice.

METHODS

A mouse colitis model was constructed with wild-type (WT) and TLR4-knockout (KO) mice. Fecal microbiota was transplanted by gavage. Colon inflammation severity was measured by disease activity index (DAI) scoring and hematoxylin and eosin staining. Gut microbiota structure was analyzed through 16S ribosomal RNA sequencing. Gene expression in the mouse colon was obtained by transcriptome sequencing.

RESULTS

The KO (DSS + Water) and KO (DSS + FMT) groups displayed indistinguishable body weight loss, colon length, DAI score, and histology score, which showed that FMT could not inhibit the disease in KO mice. In mice treated with FMT, the relative abundance of Akkermansia decreased, and Lactobacillus became dominant. In particular, compared with those in WT mice, the scores of DAI and colon histology were clearly decreased in the KO-DSS group. Microbiota structure showed a significant difference between KO and WT mice. Akkermansia were the dominant genus in healthy KO mice. The ineffectiveness of FMT in KO mice was related to the decreased abundance of Akkermansia. Gene Ontology enrichment analysis showed that differentially expressed genes between each group were mainly involved in cytoplasmic translation and cellular response to DNA damage stimulus. The top nine genes correlating with Akkermansia included Aqp4, Clca4a, Dpm3, Fau, Mcrip1, Meis3, Nupr1 L, Pank3, and Rps13 (|R| > 0.9, P < 0.01).

CONCLUSION

FMT may ameliorate DSS-induced colitis by regulating the TLR4 signaling pathway. TLR4 modulates the composition of gut microbiota and the expression of related genes to ameliorate colitis and maintain the stability of the intestinal environment. Akkermansia bear great therapeutic potential for colitis.