Hypoxia ameliorates intestinal inflammation through NLRP3/mTOR downregulation and autophagy activation

Role of Pyroptosis in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a serious chronic condition marked by persistent and recurrent intestinal ulcers. Although the exact cause of IBD remains unclear, it is generally accepted that a complex interaction among dietary factors, gut microbiota, and immune responses in genetically predisposed individuals contributes to its development. Pyroptosis, an inflammatory form of programmed cell death activated by inflammasomes, is marked by the rupture of cell membranes and the subsequent release of inflammatory mediators. Emerging evidence indicates that pyroptosis plays a crucial role in the pathogenesis of IBD. Moderate pyroptosis activation can enhance intestinal immune defenses, while excessive inflammasome activation can trigger an inflammatory cascade, resulting in increased damage to intestinal tissues. This article reviews the molecular mechanisms underlying pyroptosis and highlights its role in the onset and progression of IBD. Furthermore, We explore recent advancements in IBD treatment, focusing on small molecule compounds that specifically target and inhibit pyroptosis.

Pyroptosis and its role in intestinal ischemia-reperfusion injury: a potential therapeutic target

Intestinal ischemia-reperfusion injury (II/RI) is a critical acute condition characterized by complex pathological mechanisms, including various modes of cell death. Among these, pyroptosis has garnered significant attention in recent years. This review explores the characteristics, molecular mechanisms, and implications of pyroptosis in II/RI, with a focus on therapeutic strategies targeting the pyroptosis pathway. Key processes such as NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation, caspase-1 activation, and gasdermin D (GSDMD)-mediated membrane pore formation are identified as central to pyroptosis. Compounds like MCC950, CY-09, metformin, and curcumin have shown promise in attenuating II/RI in preclinical studies by modulating these pathways. However, challenges remain in understanding non-canonical pyroptosis pathways, unraveling the exact mechanisms of GSDMD-induced pore formation, and translating these findings into clinical applications. Addressing these gaps will be crucial for developing innovative and effective treatments for II/RI.

H4K12 lactylation-regulated NLRP3 is involved in cigarette smoke-accelerated Alzheimer-like pathology through mTOR-regulated autophagy and activation of microglia

Cigarette smoke (CS), an indoor environmental pollution, is an environmental risk factor for diverse neurological disorders. However, the neurotoxicological effects and mechanisms of CS on Alzheimer's disease (AD) progression remain unclear. We found that CS accelerated the progression of AD, including increasing β-amyloid (Aβ) plaque deposition and exacerbating cognitive decline. Mechanistically, CS exposure increased the levels of NOD-like receptor protein 3 (NLRP3), which impaired autophagic flux in microglia by activating the mammalian target of rapamycin (mTOR) signal. Metabolomics analysis revealed an upregulation of lactate levels and an increase in global protein lysine lactylation in the brain tissue of CS-exposed AD-transgenic mice. Immunoprecipitation-Mass Spectrometry and chromatin immunoprecipitation assays demonstrated that CS elevates H4K12 lactylation (H4K12la) levels, which accumulate at the promoter region of NLRP3, leading to the activation of its transcription. Via inhibiting lactate or NLRP3 activation, oxamate and MCC950 alleviates these CS-induced effects. Therefore, our data suggest that the CS-induced increase in lactate levels triggers NLRP3 transcriptional activation through H4K12la, which subsequently leads to mTOR-mediated autophagy dysfunction in microglia, promoting microglial activation and resulting in Aβ plaque accumulation in AD-transgenic mice. This provides a new mechanism and potential therapeutic target for AD associated with environmental factors.

Updated insights into the molecular networks for NLRP3 inflammasome activation

Over the past decade, significant advances have been made in our understanding of how NACHT-, leucine-rich-repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasomes are activated. These findings provide detailed insights into the transcriptional and posttranslational regulatory processes, the structural-functional relationship of the activation processes, and the spatiotemporal dynamics of NLRP3 activation. Notably, the multifaceted mechanisms underlying the licensing of NLRP3 inflammasome activation constitute a focal point of intense research. Extensive research has revealed the interactions of NLRP3 and its inflammasome components with partner molecules in terms of positive and negative regulation. In this Review, we provide the current understanding of the complex molecular networks that play pivotal roles in regulating NLRP3 inflammasome priming, licensing and assembly. In addition, we highlight the intricate and interconnected mechanisms involved in the activation of the NLRP3 inflammasome and the associated regulatory pathways. Furthermore, we discuss recent advances in the development of therapeutic strategies targeting the NLRP3 inflammasome to identify potential therapeutics for NLRP3-associated inflammatory diseases. As research continues to uncover the intricacies of the molecular networks governing NLRP3 activation, novel approaches for therapeutic interventions against NLRP3-related pathologies are emerging.

NLRP3 inflammasome-mediated premature immunosenescence drives diabetic vascular aging dependent on the induction of perivascular adipose tissue dysfunction

AIMS

The vascular aging process accelerated by type 2 diabetes mellitus (T2DM) is responsible for the elevated risk of associated cardiovascular diseases. Metabolic disorder-induced immune senescence has been implicated in multi-organ/tissue damage. Herein, we sought to determine the role of immunosenescence in diabetic vascular aging and to investigate the underlying mechanisms.

METHODS AND RESULTS

Aging hallmarks of the immune system appear prior to the vasculature in streptozotocin (STZ)/high-fat diet (HFD)-induced T2DM mice or db/db mice. Transplantation of aged splenocytes or diabetic splenocytes into young mice triggered vascular senescence and injury compared with normal control splenocyte transfer. RNA sequencing profile and validation in immune tissues revealed that the toll-like receptor 4-nuclear factor-kappa B-NLRP3 axis might be the mediator of diabetic premature immunosenescence. The absence of Nlrp3 attenuated immune senescence and vascular aging during T2DM. Importantly, senescent immune cells, particularly T cells, provoked perivascular adipose tissue (PVAT) dysfunction and alternations in its secretome, which in turn impair vascular biology. In addition, senescent immune cells may uniquely affect vasoconstriction via influencing PVAT. Lastly, rapamycin alleviated diabetic immune senescence and vascular aging, which may be partly due to NLRP3 signalling inhibition.

CONCLUSION

These results indicated that NLRP3 inflammasome-mediated immunosenescence precedes and drives diabetic vascular aging. The contribution of senescent immune cells to vascular aging is a combined effect of their direct effects and induction of PVAT dysfunction, the latter of which can uniquely affect vasoconstriction. We further demonstrated that infiltration of senescent T cells in PVAT was increased and associated with PVAT secretome alterations. Our findings suggest that blocking the NLRP3 pathway may prevent early immunosenescence and thus mitigate diabetic vascular aging and damage, and targeting senescent T cells or PVAT might also be the potential therapeutic approach.

NLRP3 inflammasome: significance and potential therapeutic targets to advance solid organ transplantation

INTRODUCTION

NOD-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome, integral to innate immunity, has become a pivotal figure in the inflammatory cascade.

AREAS COVERED

This article provides an overview of the NLRP3 inflammasome, reviewing its complicated structure, as well as the diverse signals that trigger its assembly. Furthermore, we explored the intricate relationship between the NLRP3 inflammasome and acute and chronic rejection in solid organ transplantation. Solid organ transplantation stands as a crucial medical intervention, yet its efficacy is challenged by immune-mediated complications, including acute rejection, ischemia-reperfusion injury, and chronic allograft rejection. We also investigated the encouraging potential of immunosuppressive therapies targeting NLRP3 signaling to alleviate inflammatory responses linked to transplantation.

EXPERT OPINION

In recent years, the NLRP3 inflammasome has garnered considerable attention owing to its critical functions spanning diverse fields. This study highlights the critical function of the NLRP3 inflammasome and presents insights, offering fresh perspectives on how its modulation might help to improve the outcomes among patients who undergo solid organ transplantations.

Multifunctional chrysin-loaded gallic acid-glycerol monostearate conjugate-based injectable hydrogel for targeted inhibition of hypoxia-induced NLRP3 inflammasome in ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory condition affecting the colon part of the large intestine. Since there is no cure for this disease, conventional therapies only provide symptomatic relief. Recently, phytomolecules have shown promising treatment results in various diseases. However, short half-life, hydrophobicity, and poor bioavailability limit their therapeutic potential. To overcome all these challenges, we have earlier conjugated a phytomolecule (gallic acid) (GA) with the FDA-approved generally recognized as safe (GRAS) material that is glycerol monostearate (GMS). This GA-GMS conjugate self-assembles as a hydrogel via the heating-cooling method and acts as a pro-drug of GA. The in vivo imaging results suggest that the GA-GMS hydrogel more efficiently adheres to the inflamed colon than a therapeutic enema. Additionally, it is known that the gut microbiota exaggerates UC by creating a hypoxic environment in the colon. This hypoxia is linked with NLRP3 inflammasome activation that triggers the release of IL-1β and IL-18 that downregulates MUC2 protein expression in the colon, responsible for mucin secretion in the colon. Therefore, chrysin (CR) (HIF-1α inhibitor) is encapsulated into the GA-GMS hydrogel to target hypoxia. The CR@GA-GMS hydrogel follows the enzyme-responsive release of the CR and restores DSS-induced damage to colonic tissue. Furthermore, the CR@GA-GMS hydrogel downregulates HIF-1α mediated NLRP3 inflammasome signalling while upregulating MUC2 production.

Gut commensal Alistipes shahii improves experimental colitis in mice with reduced intestinal epithelial damage and cytokine secretion

The commensal bacterium Alistipes shahii is a core microbe of the human gut microbiome and its abundance is negatively correlated with inflammatory bowel diseases (IBDs). However, its fundamental role in regulating inflammatory response remains unknown. Using a dextran sulfate sodium (DSS)-induced colitis mouse model, we examined the effect of A. shahii strain As360 intervention on host inflammatory response and found that A. shahii As360 alleviated disease activity index, colon shortening, and colonic histopathological lesion. The levels of tight junction proteins (mainly ZO1 and claudin-1) were decreased in DSS-induced colitis mice, whereas the levels of these proteins were elevated in colitis mice with A. shahii As360 treatment. In addition, A. shahii As360 treatment led to alterations in cytokine release, especially an increase of IL10. It also led to reduced expressions of mtor and Nlrp3 and increased expression of mTOR inhibitor Ddit4 at the transcriptional level. 16S rRNA amplicon sequencing found that Bacteroides, a producer of short-chain fatty acids (SCFAs), was enriched in the fecal samples of mice with A. shahii treatment. Metabolic analyses found that, following A. shahii As360 treatment, the SCFAs in the fecal content was increased whereas lactic acid was decreased in the cecal content. These findings suggest that supplementation with A. shahii As360 is a promising strategy to prevent colitis.IMPORTANCEAs one of the core microbes and keystone species in the human gut, Alistipes shahii has the potential to inhibit inflammation and improve inflammatory bowel diseases (IBDs) conditions. In this study, we experimentally demonstrated that oral administration of A. shahii As360 alleviated symptoms of colitis, altered the release of cellular inflammatory factors, reduced the intestinal epithelial barrier damage, and changed gut microbiota and fecal metabolites. These findings provide a deeper understanding of the beneficial effects of A. shahii and its perspective for better strategies to prevent IBD.

Lactobacillus plantarum SMUM211204 Exopolysaccharides Have Tumor-Suppressive Effects on Colorectal Cancer by Regulating Autophagy via the mTOR Pathway

Probiotics have demonstrated their ability to suppress tumors in cell lines and mouse models. However, the precise molecules responsible for these effects remain unidentified. We focused on isolating and analyzing the exopolysaccharides (EPSs) produced by Lactobacillus plantarum (L. plantarum) SMUM211204. Our findings confirm that EPSs impair the growth of HCT116 cells and induce autophagy and apoptosis. Moreover, further experimental evidence demonstrates that EPSs diminish the expression of phosphorylation levels of PI3K, AKT, and mTOR. In contrast, they boost the expression of AMPKa, elevate the ULK1 level, and increase the protein LC3-II/I ratio. Furthermore, when rapamycin is employed to impede EPS-induced autophagy, it results in an enhancement of apoptosis and cell death in HCT116 cells. To validate these findings in vivo, we conducted an animal study using a colorectal cancer xenograft model. The results showed a significant reduction in tumor volume and weight in the EPS-treated group compared with the control group. Immunohistochemical analysis of tumors indicated increased expressions of LC3 and caspase-3, along with decreased levels of phospho-PI3Kinase, phospho-AKT, and P62, consistent with in vitro findings. Our study proved that EPSs have an inhibitory effect on colorectal cancer and can be used as a preventive and therapeutic drug for cancer.

Redox regulation: mechanisms, biology and therapeutic targets in diseases

Redox signaling acts as a critical mediator in the dynamic interactions between organisms and their external environment, profoundly influencing both the onset and progression of various diseases. Under physiological conditions, oxidative free radicals generated by the mitochondrial oxidative respiratory chain, endoplasmic reticulum, and NADPH oxidases can be effectively neutralized by NRF2-mediated antioxidant responses. These responses elevate the synthesis of superoxide dismutase (SOD), catalase, as well as key molecules like nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione (GSH), thereby maintaining cellular redox homeostasis. Disruption of this finely tuned equilibrium is closely linked to the pathogenesis of a wide range of diseases. Recent advances have broadened our understanding of the molecular mechanisms underpinning this dysregulation, highlighting the pivotal roles of genomic instability, epigenetic modifications, protein degradation, and metabolic reprogramming. These findings provide a foundation for exploring redox regulation as a mechanistic basis for improving therapeutic strategies. While antioxidant-based therapies have shown early promise in conditions where oxidative stress plays a primary pathological role, their efficacy in diseases characterized by complex, multifactorial etiologies remains controversial. A deeper, context-specific understanding of redox signaling, particularly the roles of redox-sensitive proteins, is critical for designing targeted therapies aimed at re-establishing redox balance. Emerging small molecule inhibitors that target specific cysteine residues in redox-sensitive proteins have demonstrated promising preclinical outcomes, setting the stage for forthcoming clinical trials. In this review, we summarize our current understanding of the intricate relationship between oxidative stress and disease pathogenesis and also discuss how these insights can be leveraged to optimize therapeutic strategies in clinical practice.

Programmed Transformation of Osteogenesis Microenvironment by a Multifunctional Hydrogel to Enhance Repair of Infectious Bone Defects

Repair of infectious bone defects remains a serious problem in clinical practice owing to the high risk of infection and excessive reactive oxygen species (ROS) during the early stage, and the residual bacteria and delayed Osseo integrated interface in the later stage, which jointly creates a complex and dynamic microenvironment and leads to bone non-union. The melatonin carbon dots (MCDs) possess antibacterial and osteogenesis abilities, greatly simplifying the composition of a multifunctional material. Therefore, a multifunctional hydrogel containing MCDs (GH-MCD) is developed to meet the multi-stage and complex repair needs of infectious bone injury in this study. The GH-MCD can intelligently release MCDs responding to the acidic microenvironment to scavenge intracellular ROS and exhibit good antibacterial activity by inducing the production of ROS in bacteria and inhibiting the expression of secA2. Moreover, it has high osteogenesis and long-lasting antimicrobial activity during bone repair. RNA-seq results reveal that the hydrogels promote the repair of infected bone healing by enhancing cellular resistance to bacteria, balancing osteogenesis and osteoclastogenesis, and regulating the immune microenvironment. In conclusion, the GH-MCD can promote the repair of infectious bone defects through the programmed transformation of the microenvironment, providing a novel strategy for infectious bone defects.

Novel susceptibility genes and biomarkers for obstructive sleep apnea: insights from genetic and inflammatory proteins

STUDY OBJECTIVES

Numerous observational studies link obstructive sleep apnea (OSA) to inflammatory proteins, yet the directionality of these associations remains ambiguous. Therefore, we aimed to clarify the potential associations of gene-predicted inflammatory proteins with OSA.

METHODS

Based on genome-wide association study data, we applied Mendelian randomization (MR) to explore potential connections between circulating inflammatory proteins and OSA, primarily using the inverse-variance weighting method for robustness. Cochran's Q test, MR‒Egger intercept test, MR-PRESSO, and leave-one-out method were used to perform sensitivity tests for pleiotropy and heterogeneity. Replication analyses and meta-analyses were performed using other independent data. Steiger tests and multivariate MR assessed the independent effects of exposure factors, and the functional mapping and annotation (FUMA) platform was used to identify key genes to enhance the understanding of genetics.

RESULTS

Our investigation revealed 21 circulating inflammatory proteins significantly associated with OSA-related phenotypes. Notably, IL-10RA, IL-18R1, TNFSF14, CCL23, ADA, and SLAMF1 had significant effects on multiple phenotypes. After FDR correction, IL-18R1, SLAMF1, IL-10RA, and IL-17C were identified as important candidates for OSA, and multivariate MR analysis strengthened the independent heritability of 20 inflammatory factors. The FUMA platform revealed seven overlapping genes: ROBO1, PRIM1, NACA, SHBG, HSD17B6, RBMS2, and WWOX. All reverse MR analyses and sensitivity analyses confirmed the robustness of these associations.

CONCLUSIONS

Our results underscore crucial associations between inflammatory proteins and OSA pathogenesis, revealing new correlates and susceptibility genes. These findings advance biomarker identification for OSA risk and highlight the importance of genetic and inflammatory profiles in OSA management.

Targeting NCAPD2 as a Therapeutic Strategy for Crohn's Disease: Implications for Autophagy and Inflammation

BACKGROUND

Our earlier studies identified that non-SMC condensin I complex subunit D2 (NCAPD2) induces inflammation through the IKK/NF-κB pathway in ulcerative colitis. However, its role in the development of Crohn's disease (CD) and the specific molecular mechanism still need to be further studied.

METHODS

NCAPD2 expression in clinical ileal CD mucosa vs normal mucosa was examined, alongside its correlation with CD patients' clinical characteristics via their medical records. The biological function and molecular mechanism of NCAPD2 in CD were explored using a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced CD mouse model, along with immunofluorescence, western blot, quantitative real-time PCR, immunohistochemistry, hematoxylin and eosin staining, and cell functional analysis.

RESULTS

NCAPD2 was overexpressed in CD tissues and significantly correlated with disease activity in CD patients (P = .016). In a TNBS-induced CD mouse model, NCAPD2 knockdown inhibited the development of TNBS-induced intestinal inflammation in mice. In addition, we found that NCAPD2 inhibited autophagy. Mechanistically, NCAPD2 promoted the phosphorylation of mammalian target of the rapamycin (mTOR) and its direct effector S6K and downregulated the expression of autophagy-related proteins Beclin1, LC3II, and Atg5. In addition, NCAPD2 activates the NF-κB signaling pathway, and the downstream inflammatory factors are continuously released, leading to the persistence of inflammation.

CONCLUSIONS

Our results show that NCAPD2 suppresses autophagy and worsens intestinal inflammation by modulating mTOR signaling and impacting the NF-κB pathway, suggesting a critical role in CD progression. Targeting NCAPD2 could be a promising therapeutic approach to stop CD advancement.

Interaction Between Autophagy and the Inflammasome in Human Tumors: Implications for the Treatment of Human Cancers

Autophagy is a physiologically regulated cellular process orchestrated by autophagy-related genes (ATGs) that, depending on the tumor type and stage, can either promote or suppress tumor growth and progression. It can also modulate cancer stem cell maintenance and immune responses. Therefore, targeted manipulation of autophagy may inhibit tumor development by overcoming tumor-promoting mechanisms. The inflammasome is another multifunctional bioprocess that induces a form of pro-inflammatory programmed cell death, called pyroptosis. Dysregulation or overactivation of the inflammasome has been implicated in tumor pathogenesis and development. Additionally, autophagy can inhibit the NLRP3 inflammasome by removing inflammatory drivers. Recent research suggests that the NLRP3 inflammasome, in turn, affects autophagy. Understanding the complex interplay between autophagy and inflammasomes could lead to more precise and effective strategies for cancer treatments. In this review, we summarize the impact of autophagy and inflammasome dysregulation on tumor progression or suppression. We then highlight their targeting for cancer treatment as monotherapy or in combination with other therapies. Furthermore, we discuss the interaction between autophagy and tumor-promoting inflammation or the NLRP3 inflammasome. Finally, based on recent findings, we review the potential of this interaction for cancer treatment.

Sishen Pill & Tongxieyaofang ameliorated ulcerative colitis through the activation of HIF-1α acetylation by gut microbiota-derived propionate and butyrate

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory bowel disease closely related to gut microbiota dysbiosis and intestinal homeostasis imbalance. Sishen Pill&Tongxieyaofang (SSP-TXYF) has a long history of application in traditional Chinese medicine and is widely used in UC clinics. However, its mechanism of action is still unclear.

PURPOSE

This study aimed to explore the potential regulatory role of SSP-TXYF in protecting against UC through metabolites produced by the intestinal microbiota, and elucidate its underlying molecular mechanism.

STUDY DESIGN AND METHODS

16S rRNA and UPLC-QE-Orbitrap-MS were used to assess the microbiota and short-chain fatty acids (SCFAs). A rat model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced gut microbiota dysbiosis was used to study the effects of SSP-TXYF on UC in vivo. Intestinal epithelial cells-6 (IEC-6) were treated with lipopolysaccharide (LPS). The intestinal mucosal barrier (IMB) functions were investigated by alcian blue staining and western blot analysis. The mechanism of SSP-TXYF influenced the HIF-1α acetylation pathway was examined by real-time fluorescence quantitative PCR (qPCR), Western blotting, and Co-immunoprecipitation.

RESULTS

Using 16S rRNA gene-based microbiota analysis, we found that SSP-TXYF ameliorated TNBS-induced gut microbiota dysbiosis. We found that SSP-TXYF significantly inhibited the decreased abundance of Firmicutes in UC rats, in addition, the abundance of Actinobacteria was also improved. The mechanism of SSP-TXYF-treated TNBS-induced UC resulted from improved IMB functions via the activation of hypoxia-inducible factor-1 (HIF-1α) acetylation. Notably, SSP-TXYF Enriched microbiota-derived metabolites propionate and butyrate, which could activate HIF-1α acetylation in IEC. Furthermore, exogenous treatment of propionate and butyrate reproduced similar protective effects as SSP-TXYF to UC through improving HIF-1α-dependent IMB functions.

CONCLUSIONS

Overall, our findings suggest that the gut microbiota-propionate/butyrate-HIF-1α-IMB axis plays an important role in SSP-TXYF-maintaining intestinal homeostasis, which may represent a novel approach for UC prevention via the intervention of any link in this axis.

Translational characterization of immune pathways in inflammatory bowel disease: insights for targeted treatments

INTRODUCTION

The pathogenesis of inflammatory bowel disease (IBD) involves the dysregulation of multiple inflammatory pathways. The understanding of these mechanisms allows their selective targeting for therapeutic purposes. The discovery of Tumor Necrosis Factor-alpha's (TNF-α) role in mucosal inflammation ushered an exciting new era of drug development which now comprises agents targeting multiple pro-inflammatory signaling pathways, integrins, and leukocyte trafficking regulators.

AREA COVERED

This review provides an overview of the main molecular players of IBD, their translation into therapeutic targets and the successful development of the advanced agents modulating them. We combine basic science with clinical trials data to present a critical review of both the successful and failed drug development programs. A PubMed literature search was conducted to delve into the available literature and clinical trials.

EXPERT OPINION

The treatment landscape for IBD has rapidly expanded, particularly with the development of biologics targeting TNF-α, integrins, and S1P modulators, as well as newer agents such as IL-12/IL-23 inhibitors and JAK inhibitors, offering robust efficacy and safety profiles. However, challenges persist in understanding and effectively treating difficult-to-treat IBD, highlighting the need for continued research to uncover novel therapeutic targets and optimize patient outcomes.

Hypoxia-Inducible Factor-1α Modulates the Toll-Like Receptor 4/Nuclear Factor Kappa B Signaling Pathway in Experimental Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a devastating disease observed in premature infants, characterized by intestinal ischemia and inflammation. Hypoxia-inducible factor-1 alpha (HIF-1α), a master regulator of the cellular response to hypoxia and ischemia, plays a critical role in NEC pathogenesis. However, the precise mechanisms by which HIF-1α influences the intestines in NEC remain poorly understood. Herein, we aimed to explore the role of HIF-1α in NEC using a transgenic mouse model. We induced NEC in neonatal mice from postnatal day 5 to 9, and various parameters, including intestinal injury, oxidative stress, inflammatory responses, intestinal epithelial cell (IEC) proliferation, and apoptosis, were assessed. The results confirmed that the absence of intestinal epithelial HIF-1α increased the susceptibility of mice to NEC-induced intestinal injury, as evidenced by increased oxidative stress, inflammatory responses, apoptosis, and inhibition of proliferation. Additionally, we observed an upregulation of the Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway specifically in the intestines of mice lacking HIF-1α in IECs (HIF-1αΔIEC) with NEC. These findings provide crucial insights into the role of HIF-1α in regulating intestinal oxidative stress and inflammation to maintain intestinal homeostasis, highlighting its association with the TLR4-NF-κB signaling pathway. Furthermore, these insights might lead to the identification of novel therapeutic targets for the treatment of NEC.

New insight in treating autoimmune diseases by targeting autophagy

Autophagy is a highly conserved biological process in eukaryotes, which degrades cellular misfolded proteins, damaged organelles and invasive pathogens in the lysosome-dependent manner. Autoimmune diseases caused by genetic elements, environments and aberrant immune responses severely impact patients' living quality and even threaten life. Recently, numerous studies have reported autophagy can regulate immune responses, and play an important role in autoimmune diseases. In this review, we summarised the features of autophagy and autophagy-related genes, enumerated some autophagy-related genes involved in autoimmune diseases, and further overviewed how to treat autoimmune diseases through targeting autophagy. Finally, we outlooked the prospect of relieving and curing autoimmune diseases by targeting autophagy pathway.

Mechanisms and cross-talk of regulated cell death and their epigenetic modifications in tumor progression

Cell death is a fundamental part of life for metazoans. To maintain the balance between cell proliferation and metabolism of human bodies, a certain number of cells need to be removed regularly. Hence, the mechanisms of cell death have been preserved during the evolution of multicellular organisms. Tumorigenesis is closely related with exceptional inhibition of cell death. Mutations or defects in cell death-related genes block the elimination of abnormal cells and enhance the resistance of malignant cells to chemotherapy. Therefore, the investigation of cell death mechanisms enables the development of drugs that directly induce tumor cell death. In the guidelines updated by the Cell Death Nomenclature Committee (NCCD) in 2018, cell death was classified into 12 types according to morphological, biochemical and functional classification, including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, PARP-1 parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence and mitotic catastrophe. The mechanistic relationships between epigenetic controls and cell death in cancer progression were previously unclear. In this review, we will summarize the mechanisms of cell death pathways and corresponding epigenetic regulations. Also, we will explore the extensive interactions between these pathways and discuss the mechanisms of cell death in epigenetics which bring benefits to tumor therapy.

Involvement of gut microbiota recovery and autophagy induction in Youhua Kuijie formula's protection against experimental ulcerative colitis

Ulcerative colitis (UC) is characterized by overactive inflammatory response, impaired intestinal mucosal barrier and disrupted gut microbiota. Youhua Kuijie formula is a classic empirical prescription based on the pathogenesis of UC. The present study was designed to verify the protective effect of Youhua Kuijie formula on DSS-induced UC in mice and uncover the related mechanism. Youhua Kuijie formula were orally administrated to UC mice induced by DSS dissolved in drinking water for ten days. The protective effect of Youhua Kuijie formula was evidenced by reduced pathological symptoms accompanied by palliative inflammatory response and relatively intact intestinal barrier. The data from 16S rRNA gene sequencing and GC-MS untargeted metabolomics indicated that the supplement of Youhua Kuijie formula restructured gut microbiota community structure, and thereby modulated the metabolic profiles in UC mice. The analysis of pathway enrichment analysis suggested the major alterations in metabolic pathway were related to protein digestion and absorption. Besides, the results of the following experiments suggested that Youhua Kuijie formula treatment increased adenosine monophosphate-activated protein kinase (AMPK) activation, decreased mechanistic target of rapamycin (mTOR) phosphorylation, and thereby reversing autophagy deficiency in the intestinal tract of UC mice. Collectively, our results demonstrated that the regulation of AMPK/mTOR was involved in Youhua Kuijie formula administration mediated protective effect on UC.

Non-coding RNAs as a Critical Player in the Regulation of Inflammasome in Inflammatory Bowel Diseases; Emphasize on lncRNAs

Inflammatory bowel disease (IBD) is an idiopathic disease caused by a dysregulated immune response to host intestinal microflora. A hyperactive inflammatory and immunological response in the gut has been shown to be one of the disease's long-term causes despite the complexity of the clinical pathology of IBD. The innate immune system activator known as human gut inflammasome is thought to be a significant underlying cause of pathology and is closely linked to the development of IBD. It is essential to comprehend the function of inflammasome activation in IBD to treat it effectively. Systemic inflammasome regulation may be a proper therapeutic and clinical strategy to manage IBD symptoms since inflammasomes may have a significant function in IBD. Non-coding RNAs (ncRNAs) are a type of RNA transcript that is incapable of encoding proteins or peptides. In IBD, inflammation develops and worsens as a result of its imbalance. Culminating evidence has been shown that ncRNAs, and particularly long non-coding RNAs (lncRNAs), may play a role in the regulation of NLR family pyrin domain containing 3 (NLRP3) inflammasome activation in IBD. The relationship between IBD and the gut inflammasome, as well as current developments in IBD research and treatment approaches, have been the main topics of this review. We have covered inflammasomes and their constituents, results from in vivo research, inflammasome inhibitors, and advancements in inflammasome-targeted therapeutics for IBD.

Acute hypoxic conditions preceding endotoxin administration result in an increased proinflammatory cytokine response in healthy men

Tissues often experience hypoxia at sites of inflammation due to malperfusion, massive immune cell recruitment, and increased oxygen consumption. Organisms adapt to these hypoxic conditions through the transcriptional activation of various genes. In fact, there is significant crosstalk between the transcriptional responses to hypoxia and inflammatory processes. This interaction, named inflammatory hypoxia, plays a crucial role in various diseases including malignancies, chronic inflammatory lung diseases, and sepsis. To further elucidate the crosstalk between hypoxia and inflammation in vivo and assess its potential for innovative therapies, our study aimed at investigating the impact of acute hypoxic conditions on inflammation-induced immune responses. To this end, we exposed healthy human subjects to hypoxia either before (hypoxia priming) or after a single intravenous (i.v.) injection of 0.4 ng/kg LPS. Our data show that hypoxia exposure prior to LPS injection (hypoxia priming) amplified the proinflammatory response. This was reflected by an increase in body temperature, plasma noradrenaline levels, and the production of proinflammatory cytokines (i.e., IL-6 and TNF-α), compared with LPS control conditions. These effects were not observed when participants were exposed to hypoxia after LPS administration, demonstrating that the interaction between hypoxia and inflammation highly depends on the timing of both stimuli. Our findings suggest that acute hypoxia (i.e., hypoxia priming) modulates transient inflammation, leading to an enhanced proinflammatory response in healthy human subjects. This highlights the need for further investigations to understand the pathology of various hypoxia-inducible factor (HIF)-associated inflammatory diseases and to develop suitable, innovative therapies.NEW & NOTEWORTHY To our knowledge, this is the first in vivo study investigating the effects of hypoxia preceding (hypoxia priming) or following LPS administration on the endotoxin-induced inflammatory response in healthy human subjects. The data show that hypoxia priming amplified the proinflammatory response, reflected by an increased body temperature, increased plasma noradrenaline levels, and higher production of proinflammatory cytokines (i.e., IL-6 and TNF-α) compared with LPS control conditions.

Nano-vibration exciter: Hypoxia-inducible factor 1 signaling pathway-mediated extracellular vesicles as bioactive glass substitutes for bone regeneration

Bioactive glasses (BG) play a vital role in angiogenesis and osteogenesis through releasing functional ions. However, the rapid ion release in the early stage will cause excessive accumulation of metal ions, which in turn leads to obvious cytotoxicity, long-term inflammation, and bone repair failure. Inspired by the vibration exciter, small extracellular vesicles (sEVs) obtained by treating mesenchymal stem cells with copper-doped bioactive glass (CuBG-sEVs), is prepared as a nano-vibration exciter. The nano-vibration exciter can convert the ion signals of CuBG into biochemical factor signals through hypoxia-inducible factor 1 (HIF-1) signaling pathway and its activated autophagy, so as to better exert the osteogenic activity of BG. The results showed that CuBG extracts could significantly improve the enrichment of key miRNAs and increase the yield of CuBG-sEVs by activating HIF-1 signaling pathway and its activated autophagy. Cell experiments showed that CuBG-sEVs are favor to cell recruitment, vascularization and osteogenesis as the enrichment of key miRNAs. The animal experiments results showed that CuBG-sEVs stimulated angiogenesis mediated by CD31 and promoted bone regeneration by activating signaling pathways related to osteogenesis. These findings underscored the significant potential of sEVs as alternative strategies to better roles of BG.

LncRNA MIAT suppresses inflammation in LPS-induced J774A.1 macrophages by promoting autophagy through miR-30a-5p/SOCS1 axi

Accumulated data implicate that long noncoding RNA (lncRNA) plays a pivotal role in rheumatoid arthritis (RA), potentially serving as a competitive endogenous RNA (ceRNA) for microRNAs (miRNAs). The lncRNA myocardial infarction-associated transcript (MIAT) has been demonstrated to regulate inflammation. However, the role of MIAT in the inflammation of RA remains inadequately explored. This study aims to elucidate MIAT's role in the inflammation of lipopolysaccharide (LPS)-induced macrophages and to uncover the underlying molecular mechanisms. We observed heightened MIAT expression in LPS-induced J774A.1 cells and collagen-induced arthritis mouse models, in contrast to the expression pattern of miR-30a-5p. Silencing MIAT resulted in increased expression of the inflammatory cytokines IL-1β and TNF-α. Simultaneously, MIAT interference significantly impeded macrophage autophagy, evidenced by decreased expression of autophagy-related markers LC3-II and Beclin-1, alongside increased levels of p62 in LPS-induced J774A.1 cells. Notably, MIAT functioned as a ceRNA, sponging miR-30a-5p and exerting a negative regulatory influence on its expression. SOCS1 emerged as a target of miR-30a-5p, modulated by MIAT. Mechanistically, inhibiting miR-30a-5p reversed the impact of MIAT deficiency in promoting LPS-induced inflammation, while SOCS1 knockdown countered the cytokine inhibitory effect induced by silencing miR-30a-5p. In summary, this study indicates that lncRNA MIAT suppresses inflammation in LPS-induced J774A.1 macrophages by stimulating autophagy through the miR-30a-5p/SOCS1 axis. This suggests that MIAT holds promise as a potential therapeutic target for RA inflammation.

HIF-2α-dependent induction of miR-29a restrains TH1 activity during T cell dependent colitis

Metabolic imbalance leading to inflammatory hypoxia and stabilization of hypoxia-inducible transcription factors (HIFs) is a hallmark of inflammatory bowel diseases. We hypothesize that HIF could be stabilized in CD4+ T cells during intestinal inflammation and alter the functional responses of T cells via regulation of microRNAs. Our assays reveal markedly increased T cell-intrinsic hypoxia and stabilization of HIF protein during experimental colitis. microRNA screen in primary CD4+ T cells points us towards miR-29a and our subsequent studies identify a selective role for HIF-2α in CD4-cell-intrinsic induction of miR-29a during hypoxia. Mice with T cell-intrinsic HIF-2α deletion display elevated T-bet (target of miR-29a) levels and exacerbated intestinal inflammation. Mice with miR-29a deficiency in T cells show enhanced intestinal inflammation. T cell-intrinsic overexpression of HIF-2α or delivery of miR-29a mimetic dampen TH1-driven colitis. In this work, we show a previously unrecognized function for hypoxia-dependent induction of miR-29a in attenuating TH1-mediated inflammation.

Acetate attenuates hypothalamic pyroptosis in experimentally induced polycystic ovarian syndrome

This study hypothesized that SCFA, acetate impacts positively on hypothalamic pyroptosis and its related abnormalities in experimentally induced PCOS rat model, possibly through NrF2/HIF1-α modulation. Eight-week-old female Wister rats were divided into groups (n = 5), namely control, PCOS, acetate and PCOS + acetate groups. Induction of PCOS was performed by administering 1 mg/kg body weight of letrozole for 21 days. After PCOS confirmation, the animals were treated with 200 mg/kg of acetate for 6 weeks. Rats with PCOS were characterized with insulin resistance, leptin resistance, increased plasma testosterone as well as degenerated ovarian follicles. There was also a significant increase in hypothalamic triglyceride level, triglyceride-glucose index, inflammatory biomarkers (SDF-1 and NF-kB) and caspase-6 as well as plasma LH and triglyceride. A decrease was observed in plasma adiponectin, GnRH, FSH, and hypothalamic GABA with severe inflammasome expression in PCOS rats. These were accompanied by decreased level of NrF2/HIF1-α, and the alterations were reversed when treated with acetate. Collectively, the present results suggest the therapeutic impact of acetate on hypothalamic pyroptosis and its related comorbidity in PCOS, a beneficial effect that is accompanied by modulation of NrF2/HIF1-α.

Osteopontin deficiency promotes cartilaginous endplate degeneration by enhancing the NF-κB signaling to recruit macrophages and activate the NLRP3 inflammasome

Intervertebral disc degeneration (IDD) is a major cause of discogenic pain, and is attributed to the dysfunction of nucleus pulposus, annulus fibrosus, and cartilaginous endplate (CEP). Osteopontin (OPN), a glycoprotein, is highly expressed in the CEP. However, little is known on how OPN regulates CEP homeostasis and degeneration, contributing to the pathogenesis of IDD. Here, we investigate the roles of OPN in CEP degeneration in a mouse IDD model induced by lumbar spine instability and its impact on the degeneration of endplate chondrocytes (EPCs) under pathological conditions. OPN is mainly expressed in the CEP and decreases with degeneration in mice and human patients with severe IDD. Conditional Spp1 knockout in EPCs of adult mice enhances age-related CEP degeneration and accelerates CEP remodeling during IDD. Mechanistically, OPN deficiency increases CCL2 and CCL5 production in EPCs to recruit macrophages and enhances the activation of NLRP3 inflammasome and NF-κB signaling by facilitating assembly of IRAK1-TRAF6 complex, deteriorating CEP degeneration in a spatiotemporal pattern. More importantly, pharmacological inhibition of the NF-κB/NLRP3 axis attenuates CEP degeneration in OPN-deficient IDD mice. Overall, this study highlights the importance of OPN in maintaining CEP and disc homeostasis, and proposes a promising therapeutic strategy for IDD by targeting the NF-κB/NLRP3 axis.

Hypoxia-Induced Adaptations of Embryonic Fibroblasts: Implications for Developmental Processes

Animal embryonic development occurs under hypoxia, which can promote various developmental processes. Embryonic fibroblasts, which can differentiate into bone and cartilage and secrete various members of the collagen protein family, play essential roles in the formation of embryonic connective tissues and basement membranes. However, the adaptations of embryonic fibroblasts under hypoxia remain poorly understood. In this study, we investigated the effects of hypoxia on mouse embryonic fibroblasts (MEFs). We found that hypoxia can induce migration, promote metabolic reprogramming, induce the production of ROS and apoptosis, and trigger the activation of multiple signaling pathways of MEFs. Additionally, we identified several hypoxia-inducible genes, including Proser2, Bean1, Dpf1, Rnf128, and Fam71f1, which are regulated by HIF1α. Furthermore, we demonstrated that CoCl2 partially mimics the effects of low oxygen on MEFs. However, we found that the mechanisms underlying the production of ROS and apoptosis differ between hypoxia and CoCl2 treatment. These findings provide insights into the complex interplay between hypoxia, fibroblasts, and embryonic developmental processes.

Unraveling the Triad: Hypoxia, Oxidative Stress and Inflammation in Neurodegenerative Disorders

The mammalian brain's complete dependence on oxygen for ATP production makes it highly susceptible to hypoxia, at high altitudes or in clinical scenarios including anemia or pulmonary disease. Hypoxia plays a crucial role in the development of various brain disorders, such as Alzheimer's, Parkinson's, and other age-related neurodegenerative diseases. On the other hand, a decrease in environmental oxygen levels, such as prolonged stays at high elevations, may have beneficial impacts on the process of ageing and the likelihood of death. Additionally, the utilization of controlled hypoxia exposure could potentially serve as a therapeutic approach for age-related brain diseases. Recent findings indicate that the involvement of HIF-1α and the NLRP3 inflammasome is of significant importance in the development of Alzheimer's disease. HIF-1α serves as a pivotal controller of various cellular reactions to oxygen deprivation, exerting influence on a multitude of physiological mechanisms such as energy metabolism and inflammatory responses. The NLRP3 plays a crucial role in the innate immune system by coordinating the initiation of inflammatory reactions through the assembly of the inflammasome complex. This review examines the information pertaining to the contrasting effects of hypoxia on the brain, highlighting both its positive and deleterious effects and molecular pathways that are involved in mediating these different effects. This study explores potential strategies for therapeutic intervention that focus on restoring cellular balance and reducing neuroinflammation, which are critical aspects in addressing this severe neurodegenerative condition and addresses crucial inquiries that warrant further future investigations.

New horizons for the role of selenium on cognitive function: advances and challenges

Cognitive deficits associated with oxidative stress and the dysfunction of the central nervous system are present in some neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Selenium (Se), an essential microelement, exhibits cognition-associated functions through selenoproteins mainly owing to its antioxidant property. Due to the disproportionate distribution of Se in the soil, the amount of Se varies greatly in various foods, resulting in a large proportion of people with Se deficiency worldwide. Numerous cell and animal experiments demonstrate Se deficiency-induced cognitive deficits and Se supplementation-improved cognitive performances. However, human studies yield inconsistent results and the mechanism of Se in cognition still remains elusive, which hinder the further exploration of Se in human cognition. To address the urgent issue, the review summarizes Se-contained foods (plant-based foods, animal-based foods, and Se supplements), brain selenoproteins, mechanisms of Se in cognition (improvement of synaptic plasticity, regulation of Zn2+ level, inhibition of ferroptosis, modulation of autophagy and de novo synthesis of L-serine), and effects of Se on cognitive deficits, as well as consequently sheds light on great potentials of Se in the prevention and treatment of cognitive deficits.

FORWARD: A Learning Framework for Logical Network Perturbations to Prioritize Targets for Drug Development

Despite advances in artificial intelligence (AI), target-based drug development remains a costly, complex and imprecise process. We introduce F.O.R.W.A.R.D [ Framework for Outcome-based Research and Drug Development ], a network-based target prioritization approach and test its utility in the challenging therapeutic area of Inflammatory Bowel Diseases (IBD), which is a chronic condition of multifactorial origin. F.O.R.W.A.R.D leverages real-world outcomes, using a machine-learning classifier trained on transcriptomic data from seven prospective randomized clinical trials involving four drugs. It establishes a molecular signature of remission as the therapeutic goal and computes, by integrating principles of network connectivity, the likelihood that a drug's action on its target(s) will induce the remission-associated genes. Benchmarking F.O.R.W.A.R.D against 210 completed clinical trials on 52 targets showed a perfect predictive accuracy of 100%. The success of F.O.R.W.A.R.D was achieved despite differences in targets, mechanisms, and trial designs. F.O.R.W.A.R.D-driven in-silico phase '0' trials revealed its potential to inform trial design, justify re-trialing failed drugs, and guide early terminations. With its extendable applications to other therapeutic areas and its iterative refinement with emerging trials, F.O.R.W.A.R.D holds the promise to transform drug discovery by generating foresight from hindsight and impacting research and development as well as human-in-the-loop clinical decision-making.

NLRP3-mediated autophagy dysfunction links gut microbiota dysbiosis to tau pathology in chronic sleep deprivation

Emerging evidence indicates that sleep deprivation (SD) can lead to Alzheimer's disease (AD)-related pathological changes and cognitive decline. However, the underlying mechanisms remain obscure. In the present study, we identified the existence of a microbiota-gut-brain axis in cognitive deficits resulting from chronic SD and revealed a potential pathway by which gut microbiota affects cognitive functioning in chronic SD. Our findings demonstrated that chronic SD in mice not only led to cognitive decline but also induced gut microbiota dysbiosis, elevated NLRP3 inflammasome expression, GSK-3β activation, autophagy dysfunction, and tau hyperphosphorylation in the hippocampus. Colonization with the "SD microbiota" replicated the pathological and behavioral abnormalities observed in chronic sleep-deprived mice. Remarkably, both the deletion of NLRP3 in NLRP3 -/- mice and specific knockdown of NLRP3 in the hippocampus restored autophagic flux, suppressed tau hyperphosphorylation, and ameliorated cognitive deficits induced by chronic SD, while GSK-3β activity was not regulated by the NLRP3 inflammasome in chronic SD. Notably, deletion of NLRP3 reversed NLRP3 inflammasome activation, autophagy deficits, and tau hyperphosphorylation induced by GSK-3β activation in primary hippocampal neurons, suggesting that GSK-3β, as a regulator of NLRP3-mediated autophagy dysfunction, plays a significant role in promoting tau hyperphosphorylation. Thus, gut microbiota dysbiosis was identified as a contributor to chronic SD-induced tau pathology via NLRP3-mediated autophagy dysfunction, ultimately leading to cognitive deficits. Overall, these findings highlight GSK-3β as a regulator of NLRP3-mediated autophagy dysfunction, playing a critical role in promoting tau hyperphosphorylation.

Residual Microglia Following Short-term PLX5622 Treatment in 5xFAD Mice Exhibit Diminished NLRP3 Inflammasome and mTOR Signaling, and Enhanced Autophagy

Chronic neuroinflammation represents a prominent hallmark of Alzheimer's disease (AD). While moderately activated microglia are pivotal in clearing amyloid beta (Aβ), hyperactivated microglia perpetuate neuroinflammation. Prior investigations have indicated that the elimination of ∼80% of microglia through a month-long inhibition of the colony-stimulating factor 1 receptor (CSF1R) during the advanced stage of neuroinflammation in 5xFamilial AD (5xFAD) mice mitigates synapse loss and neurodegeneration without impacting Aβ levels. Furthermore, prolonged CSF1R inhibition diminished the development of parenchymal plaques. Nonetheless, the immediate effects of short-term CSF1R inhibition during the early stages of neuroinflammation on residual microglial phenotype or metabolic fitness are unknown. Therefore, we investigated the effects of 10-day CSF1R inhibition in three-month-old female 5xFAD mice, a stage characterized by the onset of neuroinflammation and minimal Aβ plaques. We observed ∼65% microglia depletion in the hippocampus and cerebral cortex. The leftover microglia demonstrated a noninflammatory phenotype, with highly branched and ramified processes and reduced NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome complexes. Moreover, plaque-associated microglia were reduced in number with diminished Clec7a (dectin-1) expression. Additionally, both microglia and neurons displayed reduced mechanistic target of rapamycin (mTOR) signaling and autophagy. Biochemical assays validated the inhibition of NLRP3 inflammasome activation, decreased mTOR signaling, and enhanced autophagy. However, short-term CSF1R inhibition did not influence Aβ plaques, soluble Aβ-42 levels, or hippocampal neurogenesis. Thus, short-term CSF1R inhibition during the early stages of neuroinflammation in 5xFAD mice promotes the retention of homeostatic microglia with diminished inflammasome activation and mTOR signaling, alongside increased autophagy.

Autophagy: A potential target for natural products in the treatment of ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease primarily affecting the mucosa of the colon and rectum. UC is characterized by recurrent episodes, often necessitating lifelong medication use, imposing a significant burden on patients. Current conventional and advanced treatments for UC have the disadvantages of insufficient efficiency, susceptibility to drug resistance, and notable adverse effects. Therefore, developing effective and safe drugs has become an urgent need. Autophagy is an intracellular degradation process that plays an important role in intestinal homeostasis. Emerging evidence suggests that aberrant autophagy is involved in the development of UC, and modulating autophagy can effectively alleviate experimental colitis. A growing number of studies have established that autophagy can interplay with endoplasmic reticulum stress, gut microbiota, apoptosis, and the NLRP3 inflammasome, all of which contribute to the pathogenesis of UC. In addition, a variety of intestinal epithelial cells, including absorptive cells, goblet cells, and Paneth cells, as well as other cell types like neutrophils, antigen-presenting cells, and stem cells in the gut, mediate the development of UC through autophagy. To date, many studies have found that natural products hold the potential to exert therapeutic effects on UC by regulating autophagy. This review focuses on the possible effects and pharmacological mechanisms of natural products to alleviate UC with autophagy as a potential target in recent years, aiming to provide a basis for new drug development.

Modulation of NLRP3 inflammasome-related-inflammation via RIPK1/RIPK3-DRP1 or HIF-1α signaling by phenothiazine in hypothermic and normothermic neuroprotection after acute ischemic stroke

BACKGROUND

Inflammation and subsequent mitochondrial dysfunction and cell death worsen outcomes after revascularization in ischemic stroke. Receptor-interacting protein kinase 1 (RIPK1) activated dynamin-related protein 1 (DRP1) in a NLRPyrin domain containing 3 (NLRP3) inflammasome-dependent fashion and Hypoxia-Inducible Factor (HIF)-1α play key roles in the process. This study determined how phenothiazine drugs (chlorpromazine and promethazine (C + P)) with the hypothermic and normothermic modality impacts the RIPK1/RIPK3-DRP1 and HIF-1α pathways in providing neuroprotection.

METHODS

A total of 150 adult male Sprague-Dawley rats were subjected to 2 h middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion. 8 mg/kg of C + P was administered at onset of reperfusion. Infarct volumes, mRNA and protein expressions of HIF-1α, RIPK1, RIPK3, DRP-1, NLRP3-inflammation and cytochrome c-apoptosis were assessed. Apoptotic cell death, infiltration of neutrophils and macrophages, and mitochondrial function were evaluated. Interaction between RIPK1/RIPK3 and HIF-1α/NLRP3 were determined. In SH-SY5Y cells subjected to oxygen/glucose deprivation (OGD), the normothermic effect of C + P on inflammation and apoptosis were examined.

RESULTS

C + P significantly reduced infarct volumes, mitochondrial dysfunction (ATP and ROS concentration, citrate synthase and ATPase activity), inflammation and apoptosis with and without induced hypothermia. Overexpression of RIPK1, RIPK3, DRP-1, NLRP3-inflammasome and cytochrome c-apoptosis were all significantly reduced by C + P at 33 °C and the RIPK1 inhibitor (Nec1s), suggesting hypothermic effect of C + P via RIPK1/RIPK3-DRP1pathway. When body temperature was maintained at 37 °C, C + P and HIF-1α inhibitor (YC-1) reduced HIF-1α expression, leading to reduction in mitochondrial dysfunction, NLRP3 inflammasome and cytochrome c-apoptosis, as well as the interaction of HIF-1α and NLRP3. These were also evidenced in vitro, indicating a normothermic effect of C + P via HIF-1α.

CONCLUSION

Hypothermic and normothermic neuroprotection of C + P involve different pathways. The normothermic effect was mediated by HIF-1α, while hypothermic effect was via RIPK1/RIPK3-DRP1 signaling. This provides a theoretical basis for future precise exploration of hypothermic and normothermic neuroprotection.

Biochanin a ameliorates DSS-induced ulcerative colitis by improving colonic barrier function and protects against the development of spontaneous colitis in the Muc2 deficient mice

There is an increasing appreciation that colonic barrier function is closely related to the development and progression of colitis. The mucus layer is a crucial component of the colonic barrier, responsible for preventing harmful bacteria from invading the intestinal epithelium and causing inflammation. Furthermore, a defective mucus barrier is also a significant characteristic of ulcerative colitis (UC). Biochanin A (BCA), an isoflavonoid, has garnered increasing interest due to its significant biological activities. However, the impact of BCA on UC has not been reported yet. In this study, we used a dextran sodium sulfate (DSS)-induced ulcerative colitis model and the Muc2 deficient (Muc2-/-) mice spontaneous colitis model to explore the mechanisms of BCA in the treatment of UC. Here, we verified that DSS-induced UC was observably attenuated and spontaneous colitis in Muc2-/- mice was relieved by BCA. Treatment with BCA improved colitis-related symptoms and reduced intestinal permeability by upregulating the levels of goblet cells and tight junction (TJ) proteins. In addition, we confirmed that BCA promotes autophagy through the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)/Unc-51-like kinase 1 (ULK1) pathway, thereby alleviating DSS-induced UC. In addition, the administration of BCA was able to reduce apoptosis and promote proliferation by suppressing Cleaved Caspase-3 (Cleaved Cas-3) expression, and increasing PCNA and Ki67 levels. Further research revealed that BCA treatment ameliorated spontaneous colitis and alleviated epithelial damage in Muc2-/- mice by restoring the intestinal barrier and promoting autophagy. Our results demonstrated that BCA alleviated UC by enhancing intestinal barrier function and promoting autophagy. These findings indicate that BCA may be a novel treatment alternative for UC.

Hypoxia, hypoxia-inducible factors and inflammatory bowel diseases

Adequate oxygen supply is essential for maintaining the body's normal physiological function. In chronic inflammatory conditions such as inflammatory bowel disease (IBD), insufficient oxygen reaching the intestine triggers the regulatory system in response to environmental changes. However, the pathogenesis of IBD is still under investigation. Recent research has highlighted the significant role of hypoxia in IBD, particularly the involvement of hypoxia-inducible factors (HIF) and their regulatory mechanisms, making them promising therapeutic targets for IBD. This review will delve into the role of hypoxia, HIF, and the associated hypoxia-inflammatory microenvironment in the context of IBD. Potential interventions for addressing these challenging gastrointestinal inflammatory diseases will also be discussed within this framework.

The role of epithelial cells in fibrosis: Mechanisms and treatment

Fibrosis is a pathological process that affects multiple organs and is considered one of the major causes of morbidity and mortality in multiple diseases, resulting in an enormous disease burden. Current studies have focused on fibroblasts and myofibroblasts, which directly lead to imbalance in generation and degradation of extracellular matrix (ECM). In recent years, an increasing number of studies have focused on the role of epithelial cells in fibrosis. In some cases, epithelial cells are first exposed to external physicochemical stimuli that may directly drive collagen accumulation in the mesenchyme. In other cases, the source of stimulation is mainly immune cells and some cytokines, and epithelial cells are similarly altered in the process. In this review, we will focus on the multiple dynamic alterations involved in epithelial cells after injury and during fibrogenesis, discuss the association among them, and summarize some therapies targeting changed epithelial cells. Especially, epithelial mesenchymal transition (EMT) is the key central step, which is closely linked to other biological behaviors. Meanwhile, we think studies on disruption of epithelial barrier, epithelial cell death and altered basal stem cell populations and stemness in fibrosis are not appreciated. We believe that therapies targeted epithelial cells can prevent the progress of fibrosis, but not reverse it. The epithelial cell targeting therapies will provide a wonderful preventive and delaying action.

Crosstalk between hypoxia-inducible factor-1α and short-chain fatty acids in inflammatory bowel disease: key clues toward unraveling the mystery

The human intestinal tract constitutes a complex ecosystem, made up of countless gut microbiota, metabolites, and immune cells, with hypoxia being a fundamental environmental characteristic of this ecology. Under normal physiological conditions, a delicate balance exists among these complex "residents", with disruptions potentially leading to inflammatory bowel disease (IBD). The core pathology of IBD features a disrupted intestinal epithelial barrier, alongside evident immune and microecological disturbances. Central to these interconnected networks is hypoxia-inducible factor-1α (HIF-1α), which is a key regulator in gut cells for adapting to hypoxic conditions and maintaining gut homeostasis. Short-chain fatty acids (SCFAs), as pivotal gut metabolites, serve as vital mediators between the host and microbiota, and significantly influence intestinal ecosystem. Recent years have seen a surge in research on the roles and therapeutic potential of HIF-1α and SCFAs in IBD independently, yet reviews on HIF-1α-mediated SCFAs regulation of IBD under hypoxic conditions are scarce. This article summarizes evidence of the interplay and regulatory relationship between SCFAs and HIF-1α in IBD, pivotal for elucidating the disease's pathogenesis and offering promising therapeutic strategies.

Combined administration of anisodamine and neostigmine alleviated colitis by inducing autophagy and inhibiting inflammation

Our previous work demonstrated that the anisodamine (ANI) and neostigmine (NEO) combination produced an antiseptic shock effect and rescued acute lethal crush syndrome by activating the α7 nicotinic acetylcholine receptor (α7nAChR). This study documents the therapeutic effect and underlying mechanisms of the ANI/NEO combination in dextran sulfate sodium (DSS)-induced colitis. Treating mice with ANI and NEO at a ratio of 500:1 alleviated the DSS-induced colitis symptoms, reduced body weight loss, improved the disease activity index, enhanced colon length, and alleviated colon inflammation. The combination treatment also enhanced autophagy in the colon of mice with DSS-induced colitis and lipopolysaccharide/DSS-stimulated Caco-2 cells. Besides, the ANI/NEO treatment significantly reduced INF-γ, TNF-α, IL-6, and IL-22 expression in colon tissues and decreased TNF-α, IL-1β, and IL-6 mRNA levels in Caco-2 cells. Meanwhile, the autophagy inhibitor 3-methyladenine and ATG5 siRNA attenuated these effects. Furthermore, 3-methyladenine (3-MA) and the α7nAChR antagonist methyllycaconitine (MLA) weakened the ANI/NEO-induced protection on DSS-induced colitis in mice. Overall, these results indicate that the ANI/NEO combination exerts therapeutic effects through autophagy and α7nAChR in a DSS-induced colitis mouse model.

Sacral Nerve Stimulation Alleviates Intestinal Inflammation Through Regulating the Autophagy of Macrophages and Activating the Inflammasome Mediated by a Cholinergic Antiinflammatory Pathway in Colitis Rats

BACKGROUND

Inflammatory bowel disease (IBD) is characterized by chronic progressive intestinal inflammation. Sacral nerve stimulation (SNS) ameliorates colon inflammation caused by IBD. The aim of this study was to investigate the antiinflammatory benefits of SNS in colitis rats and explore the roles of the cholinergic antiinflammatory pathway, macrophage autophagy, and nucleotide oligomerization domain-like receptor thermal protein domain associated protein 3 (NLRP3) inflammatory bodies.

MATERIALS AND METHODS

Rats were divided into four groups: healthy control, dextran sulfate sodium (DSS), DSS + sham-SNS, and DSS + SNS groups. An electrode was surgically placed in the right sacral nerve (S3) for stimulation. The disease activity index (DAI) score was recorded each day, and the degree of inflammatory injury was evaluated using hematoxylin and eosin staining. The alpha7 nicotinic acetylcholine receptor (α7nAChR) and autophagy- and NLRP3-related factors were assessed using immunofluorescence staining and Western blotting.

RESULTS

The DSS group showed a higher DAI score, colon shortening, upregulated proinflammatory action, and colon damage, and the DSS + SNS group showed significantly improved symptoms. The number of α7nAChR+ cells and the expression level of autophagy decreased in the DSS group but increased in the DSS + SNS group. Conversely, the DSS group showed increased activation of NLRP3 inflammatory bodies, whereas the DSS + SNS group showed decreased activation of NLRP3 inflammatory bodies.

CONCLUSION

In this study, SNS ameliorated colon inflammation by enhancing macrophage autophagy and inhibiting the activation of NLRP3 inflammatory bodies, which may be related to the opening of the cholinergic antiinflammatory pathway.

The HIF-1/ BNIP3 pathway mediates mitophagy to inhibit the pyroptosis of fibroblast-like synoviocytes in rheumatoid arthritis

BACKGROUND

Synovial hypoxia, a critical pathological characteristic of rheumatoid arthritis (RA), significantly contributes to synovitis and synovial hyperplasia. In response to hypoxic conditions, fibroblast-like synoviocytes (FLS) undergo adaptive changes involving gene expression modulation, with hypoxia-inducible factors (HIF) playing a pivotal role. The regulation of BCL2/adenovirus e1B 19 kDa protein interacting protein 3 (BNIP3) and nucleotide-binding oligomerization segment-like receptor family 3 (NLRP3) expression has been demonstrated to be regulated by HIF-1. The objective of this study was to examine the molecular mechanism that contributes to the aberrant activation of FLS in response to hypoxia. Specifically, the interaction between BNIP3-mediated mitophagy and NLRP3-mediated pyroptosis was conjointly highlighted.

METHODS

The research methodology employed Western blot and immunohistochemistry techniques to identify the occurrence of mitophagy in synovial tissue affected by RA. Additionally, the levels of mitophagy under hypoxic conditions were assessed using Western blot, immunofluorescence, quantitative polymerase chain reaction (qPCR), and CUT&Tag assays. Pyroptosis was observed through electron microscopy, fluorescence microscopy, and Western blot analysis. Furthermore, the quantity of reactive oxygen species (ROS) was measured. The silencing of HIF-1α and BNIP3 was achieved through the transfection of short hairpin RNA (shRNA) into cells.

RESULTS

In the present study, a noteworthy increase in the expression of BNIP3 and LC3B was observed in the synovial tissue of patients with RA. Upon exposure to hypoxia, FLS of RA exhibited BNIP3-mediated mitophagy and NLRP3 inflammasome-mediated pyroptosis. It appears that hypoxia regulates the expression of BNIP3 and NLRP3 through the transcription factor HIF-1. Additionally, the activation of mitophagy has been observed to effectively inhibit hypoxia-induced pyroptosis by reducing the intracellular levels of ROS.

CONCLUSION

In summary, the activation of FLS in RA patients under hypoxic conditions involves both BNIP3-mediated mitophagy and NLRP3 inflammasome-mediated pyroptosis. Additionally, mitophagy can suppress hypoxia-induced FLS pyroptosis by eliminating ROS and inhibiting the HIF-1α/NLRP3 pathway.

Hypoxia-Induced Signaling in Gut and Liver Pathobiology

Oxygen (O2) is essential for cellular metabolism and biochemical reactions. When the demand for O2 exceeds the supply, hypoxia occurs. Hypoxia-inducible factors (HIFs) are essential to activate adaptive and survival responses following hypoxic stress. In the gut (intestines) and liver, the presence of oxygen gradients or physiologic hypoxia is necessary to maintain normal homeostasis. While physiologic hypoxia is beneficial and aids in normal functions, pathological hypoxia is harmful as it exacerbates inflammatory responses and tissue dysfunction and is a hallmark of many cancers. In this review, we discuss the role of gut and liver hypoxia-induced signaling, primarily focusing on HIFs, in the physiology and pathobiology of gut and liver diseases. Additionally, we examine the function of HIFs in various cell types during gut and liver diseases, beyond intestinal epithelial and hepatocyte HIFs. This review highlights the importance of understanding hypoxia-induced signaling in the pathogenesis of gut and liver diseases and emphasizes the potential of HIFs as therapeutic targets.

Role of Autophagy and Pyroptosis in Intervertebral Disc Degeneration

Intervertebral disc degeneration is a chronic degenerative disease caused by the interaction of genetic and environmental factors, mainly manifested as lower back pain. At present, the diagnosis of intervertebral disc degeneration mainly relies on imaging. However, early intervertebral disc degeneration is usually insidious, and there is currently a lack of relevant clinical biomarkers that can reliably reflect early disease progression. Pyroptosis is a regulatory form of cell death triggered by the activation of inflammatory bodies and caspase, which can induce the formation of plasma membrane pores and cell swelling or lysis. Previous studies have shown that during the progression of intervertebral disc degeneration, sustained activation of inflammasomes leads to nuclear cell pyroptosis, which can occur in the early stages of intervertebral disc degeneration. Moreover, intervertebral disc nucleus pulposus cells adapt to the external environment through autophagy and maintain cellular homeostasis and studying the mechanism of autophagy in IDD and intervening in its pathological and physiological processes can provide new ideas for the clinical treatment of IDD. This review analyzes the effects of pyroptosis and autophagy on IDD by reviewing relevant literature in recent years, in order to explore the relationship between pyroptosis, autophagy and IDD.

Autophagy dysfunction contributes to NLRP1 inflammasome-linked depressive-like behaviors in mice

BACKGROUND

Major depressive disorder (MDD) is a common but severe psychiatric illness characterized by depressive mood and diminished interest. Both nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 1 (NLRP1) inflammasome and autophagy have been reported to implicate in the pathological processes of depression. However, the mechanistic interplay between NLRP1 inflammasome, autophagy, and depression is still poorly known.

METHODS

Animal model of depression was established by chronic social defeat stress (CSDS). Depressive-like behaviors were determined by social interaction test (SIT), sucrose preference test (SPT), open field test (OFT), forced swim test (FST), and tail-suspension test (TST). The protein expression levels of NLRP1 inflammasome complexes, pro-inflammatory cytokines, phosphorylated-phosphatidylinositol 3-kinase (p-PI3K)/PI3K, phosphorylated-AKT (p-AKT)/AKT, phosphorylated-mechanistic target of rapamycin (p-mTOR)/mTOR, brain-derived neurotrophic factor (BDNF), phosphorylated-tyrosine kinase receptor B (p-TrkB)/TrkB, Bcl-2-associated X protein (Bax)/B-cell lymphoma-2 (Bcl2) and cleaved cysteinyl aspartate-specific proteinase-3 (caspase-3) were examined by western blotting. The mRNA expression levels of pro-inflammatory cytokines were tested by quantitative real-time PCR. The interaction between proteins was detected by immunofluorescence and coimmunoprecipitation. Neuronal injury was assessed by Nissl staining. The autophagosomes were visualized by transmission electron microscopy. Nlrp1a knockdown was performed using an adeno-associated virus (AAV) vector containing Nlrp1a-shRNA-eGFP infusion.

RESULTS

CSDS exposure caused a bidirectional change in hippocampal autophagy function, which was activated in the initial period but impaired at the later stage. In addition, CSDS exposure increased the expression levels of hippocampal NLRP1 inflammasome complexes, pro-inflammatory cytokines, p-PI3K, p-AKT and p-mTOR in a time-dependent manner. Interestingly, NLRP1 is immunoprecipitated with mTOR but not PI3K/AKT and CSDS exposure facilitated the immunoprecipitation between them. Hippocampal Nlrp1a knockdown inhibited the activity of PI3K/AKT/mTOR signaling, rescued the impaired autophagy and ameliorated depressive-like behavior induced by CSDS. In addition, rapamycin, an autophagy inducer, abolished NLRP1 inflammasome-driven inflammatory reactions, alleviated depressive-like behavior and exerted a neuroprotective effect.

CONCLUSIONS

Autophagy dysfunction contributes to NLRP1 inflammasome-linked depressive-like behavior in mice and the regulation of autophagy could be a valuable therapeutic strategy for the management of depression.

Associations between HIFs and tumor immune checkpoints: mechanism and therapy

Hypoxia, which activates a variety of signaling pathways to enhance tumor cell growth and metabolism, is among the primary features of tumor cells. Hypoxia-inducible factors (HIFs) have a substantial impact on a variety of facets of tumor biology, such as epithelial-mesenchymal transition, metabolic reprogramming, angiogenesis, and improved radiation resistance. HIFs induce hypoxia-adaptive responses in tumor cells. Many academics have presented preclinical and clinical research targeting HIFs in tumor therapy, highlighting the potential applicability of targeted HIFs. In recent years, the discovery of numerous pharmacological drugs targeting the regulatory mechanisms of HIFs has garnered substantial attention. Additionally, HIF inhibitors have attained positive results when used in conjunction with traditional oncology radiation and/or chemotherapy, as well as with the very promising addition of tumor immunotherapy. Immune checkpoint inhibitors (CPIs), which are employed in a range of cancer treatments over the past decades, are essential in tumor immunotherapy. Nevertheless, the use of immunotherapy has been severely hampered by tumor resistance and treatment-related toxicity. According to research, HIF inhibitors paired with CPIs may be game changers for multiple malignancies, decreasing malignant cell plasticity and cancer therapy resistance, among other things, and opening up substantial new pathways for immunotherapy drug development. The structure, activation mechanisms, and pharmacological sites of action of the HIF family are briefly reviewed in this work. This review further explores the interactions between HIF inhibitors and other tumor immunotherapy components and covers the potential clinical use of HIF inhibitors in combination with CPIs.

(-)-Epigallocatechin gallate alleviates chronic unpredictable mild stress-induced depressive symptoms in mice by regulating the mTOR autophagy pathway and inhibiting NLRP3 inflammasome activation

Depression is a global public health issue that is widely studied due to the large number of people it affects and its serious consequences. Clinical studies have shown that regular tea consumption may reduce depression risk. (-)-Epigallocatechin gallate (EGCG), the main tea polyphenol, was observed to alleviate depression, but the underlying mechanism has not been elucidated. In this study, chronic unpredictable mild stress (CUMS) was used to induce depression-like behavior in mice, and behavioral tests, such as sucrose preference test and forced swim test, were performed. Then, ELISA, western blot and QT-PCR tests were used to assess the expression of the key components of the NLRP3 inflammasome and its downstream inflammatory effectors (e.g., IL-1β, IL-18), autophagy markers (Beclin-1, LC3, P62) and apoptosis markers (Bax, Bcl-2) in mouse brain tissues. Changes in serum lipid levels were also assessed. EGCG alleviated CUMS-induced depression-like behavioral changes in mice, reduced activation of the NLRP3 inflammasome, inhibited the mTOR signaling pathway, restored autophagy levels, reduced apoptosis marker expression and attenuated abnormal changes in blood lipid levels. Our study demonstrates that EGCG exerts antidepressive effects through multiple mechanisms, providing new insight into the pathological mechanism of depression and laying the foundation for the development of new therapeutic measures.

Non-coding RNAs: Emerging biomarkers and therapeutic targets in ulcerative colitis

Ulcerative colitis (UC) is a persistent inflammatory condition affecting the colon's mucosal lining, leading to chronic bowel inflammation. Despite extensive research, the precise molecular mechanisms underlying UC pathogenesis remain elusive. NcRNAs form a category of functional RNA molecules devoid of protein-coding capacity. They have recently surfaced as pivotal modulators of gene expression and integral participants in various pathological processes, particularly those related to inflammatory disorders. The diverse classes of ncRNAs, encompassing miRNAs, circRNAs, and lncRNAs, have been implicated in UC. It highlights their involvement in key UC-related processes, such as immune cell activation, epithelial barrier integrity, and the production of pro-inflammatory mediators. ncRNAs have been identified as potential biomarkers for UC diagnosis and monitoring disease progression, offering promising avenues for personalized medicine. This approach may pave the way for novel, more specific treatments with reduced side effects, addressing the current limitations of conventional therapies. A comprehensive understanding of the interplay between ncRNAs and UC will advance our knowledge of the disease, potentially leading to more effective and personalized treatments for patients suffering from this debilitating condition. This review explores the pivotal role of ncRNAs in the context of UC, shedding light on their possible targets for diagnosis, prognosis, and therapeutic interventions.

Research Progress on the Mechanism of Intestinal Barrier Damage and Drug Therapy in a High Altitude Environment

The plateau is a typical extreme environment with low temperature, low oxygen and high ultraviolet rays. The integrity of the intestinal barrier is the basis for the functioning of the intestine, which plays an important role in absorbing nutrients, maintaining the balance of intestinal flora, and blocking the invasion of toxins. Currently, there is increasing evidence that high altitude environment can enhance intestinal permeability and disrupt intestinal barrier integrity. This article mainly focuses on the regulation of the expression of HIF and tight junction proteins in the high altitude environment, which promotes the release of pro-inflammatory factors, especially the imbalance of intestinal flora caused by the high altitude environment. The mechanism of intestinal barrier damage and the drugs to protect the intestinal barrier are reviewed. Studying the mechanism of intestinal barrier damage in high altitude environment is not only conducive to understanding the mechanism of high altitude environment affecting intestinal barrier function, but also provides a more scientific medicine treatment method for intestinal damage caused by the special high altitude environment.

Role of autophagy in pathogenesis of ulcerative colitis

Ulcerative colitis is a chronic idiopathic inflammatory disease involving the colorectal mucosa. It is characterized by recurrent attacks, such as abdominal pain, diarrhea, mucus, and purulent stool. At present, the pathogenesis of ulcerative colitis is not fully understood. Most scholars generally believe that the pathogenesis of ulcerative colitis is affected by genetic susceptibility, environmental factors, immune system disorders, microflora and intestinal microflora disorders, and other factors. In recent years, the concept of autophagy has gradually attracted the attention of the scientific community, and more and more scholars have begun to study the pathogenesis of ulcerative colitis on the basis of autophagy theory. This review will give an overview of cellular autophagy and discuss its role in the pathogenesis of ulcerative colitis.