HMGB1 promotes the activation of NLRP3 and caspase-8 inflammasomes via NF-κB pathway in acute glaucoma

Irisin attenuates acute glaucoma-induced neuroinflammation by activating microglia-integrin αVβ5/AMPK and promoting autophagy

Neuroinflammation, characterized by microglial activation and the release of multiple inflammatory mediators, is a key factor in acute glaucomatous injury leading to retinal ganglion cell (RGC) death and ultimately irreversible vision loss. Irisin, a novel exercise-induced myokine, has demonstrated anti-inflammatory activity in ischemia/reperfusion injuries across multiple organs and has displayed a significant neuroprotective role in experimental stroke disease models. This study examined the protective impact of irisin and investigated its potential mechanism involved in this process utilizing an acute ocular hypertension (AOH)-induced retinal injury model in mice and a microglia inflammation model induced by lipopolysaccharide (LPS). There was a transient downregulation of irisin in the retina after AOH injury, with parallel emergence of retinal neuroinflammation and RGC death. Irisin attenuated retinal and optic nerve damage and promotes the phenotypic conversion of microglia from M1 to M2. Mechanistically, irisin significantly upregulated the expression of integrin αVβ5, p-AMPK, and autophagy-related markers. Integrin αVβ5 was highly expressed on microglia but hardly expressed on RGC. The integrin αVβ5 inhibitor cilengitide, the AMPK inhibitor dorsomorphin, and the autophagy inhibitor 3-Methyladenine (3-MA) blocked the neuroprotective effects of irisin. Our results suggest irisin attenuates acute glaucoma-induced neuroinflammation and RGC death by activating integrin αVβ5/AMPK in microglia and promoting autophagy. It should be considered a potential neuroprotective therapy for acute glaucoma.

Targeting inflammasomes and pyroptosis in retinal diseases-molecular mechanisms and future perspectives

Retinal diseases encompass various conditions associated with sight-threatening immune responses and are leading causes of blindness worldwide. These diseases include age-related macular degeneration, diabetic retinopathy, glaucoma and uveitis. Emerging evidence underscores the vital role of the innate immune response in retinal diseases, beyond the previously emphasized T-cell-driven processes of the adaptive immune system. In particular, pyroptosis, a newly discovered programmed cell death process involving inflammasome formation, has been implicated in the loss of membrane integrity and the release of inflammatory cytokines. Several disease-relevant animal models have provided evidence that the formation of inflammasomes and the induction of pyroptosis in innate immune cells contribute to inflammation in various retinal diseases. In this review article, we summarize current knowledge about the innate immune system and pyroptosis in retinal diseases. We also provide insights into translational targeting approaches, including novel drugs countering pyroptosis, to improve the diagnosis and treatment of retinal diseases.

Homer1a reduces inflammatory response after retinal ischemia/reperfusion injury

JOURNAL/nrgr/04.03/01300535-202407000-00042/figure1/v/2023-11-20T171125Z/r/image-tiff

Elevated intraocular pressure (IOP) is one of the causes of retinal ischemia/reperfusion injury, which results in NLRP3 inflammasome activation and leads to visual damage. Homer1a is reported to play a protective role in neuroinflammation in the cerebrum. However, the effects of Homer1a on NLRP3 inflammasomes in retinal ischemia/reperfusion injury caused by elevated IOP remain unknown. In our study, animal models were constructed using C57BL/6J and Homer1flox/ –/Homer1a+/ –/Nestin-Cre+/ – mice with elevated IOP-induced retinal ischemia/reperfusion injury. For in vitro experiments, the oxygen-glucose deprivation/reperfusion injury model was constructed with Müller cells. We found that Homer1a overexpression ameliorated the decreases in retinal thickness and Müller cell viability after ischemia/reperfusion injury. Furthermore, Homer1a knockdown promoted NF-κB P65Ser536 activation via caspase-8, NF-κB P65 nuclear translocation, NLRP3 inflammasome formation, and the production and processing of interleukin-1β and interleukin-18. The opposite results were observed with Homer1a overexpression. Finally, the combined administration of Homer1a protein and JSH-23 significantly inhibited the reduction in retinal thickness in Homer1flox/ –/Homer1a+/ –/Nestin-Cre+/ – mice and apoptosis in Müller cells after ischemia/reperfusion injury. Taken together, these studies demonstrate that Homer1a exerts protective effects on retinal tissue and Müller cells via the caspase-8/NF-κB P65/NLRP3 pathway after I/R injury.

Pathogenesis of depression and the potential for traditional Chinese medicine treatment

Depression is a prevalent mental disorder that significantly diminishes quality of life and longevity, ranking as one of the primary causes of disability globally. Contemporary research has explored the potential pathogenesis of depression from various angles, encompassing genetics, neurotransmitter systems, neurotrophic factors, the hypothalamic-pituitary-adrenal axis, inflammation, and intestinal flora, among other contributing factors. In addition, conventional chemical medications are plagued by delayed onset of action, persistent adverse effects, and restricted therapeutic efficacy. In light of these limitations, the therapeutic approach of traditional Chinese medicine (TCM) has gained increasing recognition for its superior effectiveness. Numerous pharmacological and clinical studies have substantiated TCM's capacity to mitigate depressive symptoms through diverse mechanisms. This article attempts to summarize the mechanisms involved in the pathogenesis of depression and to describe the characteristics of herbal medicines (including compounded formulas and active ingredients) for the treatment of depression. It further evaluates their effectiveness by correlating with the multifaceted pathogenesis of depression, thereby furnishing a reference for future research endeavors.

Caspase-8-mediated inflammation but not apoptosis drives death of retinal ganglion cells and loss of visual function in glaucomaa

Background-

Glaucoma is a complex multifactorial disease where apoptosis and inflammation represent two key pathogenic mechanisms. However, the relative contribution of apoptosis versus inflammation in axon degeneration and death of retinal ganglion cells (RGCs) is not well understood. In glaucoma, caspase-8 is linked to RGC apoptosis, as well as glial activation and neuroinflammation. To uncouple these two pathways and determine the extent to which caspase-8-mediated inflammation and/or apoptosis contributes to the death of RGCs, we used the caspase-8 D387A mutant mouse (Casp8 DA/DA ) in which a point mutation in the auto-cleavage site blocks caspase-8-mediated apoptosis but does not block caspase-8-mediated inflammation.

Methods-

Intracameral injection of magnetic microbeads was used to elevate the intraocular pressure (IOP) in wild-type, Fas deficient Faslpr, and Casp8 DA/DA mice. IOP was monitored by rebound tonometry. Two weeks post microbead injection, retinas were collected for microglia activation analysis. Five weeks post microbead injection, visual acuity and RGC function were assessed by optometer reflex (OMR) and pattern electroretinogram (pERG), respectively. Retina and optic nerves were processed for RGC and axon quantification. Two- and five-weeks post microbead injection, expression of the necrosis marker, RIPK3, was assessed by qPCR.

Results-

Wild-type, Faslpr, and Casp8 DA/DA mice showed similar IOP elevation as compared to saline controls. A significant reduction in both visual acuity and pERG that correlated with a significant loss of RGCs and axons was observed in wild-type but not in Faslpr mice. The Casp8 DA/DA mice displayed a significant reduction in visual acuity and pERG amplitude and loss of RGCs and axons similar to that in wild-type mice. Immunostaining revealed equal numbers of activated microglia, double positive for P2ry12 and IB4, in the retinas from microbead-injected wild-type and Casp8 DA/DA mutant mice. qPCR analysis revealed no induction of RIPK3 in wild-type or Casp8 DA/DA mice at two- or five-weeks post microbead injection.

Conclusions-

Our results demonstrate that caspase-8-mediated extrinsic apoptosis is not involved in the death of RGCs in the microbead-induced mouse model of glaucoma implicating caspase-8-mediated inflammation, but not apoptosis, as the driving force in glaucoma progression. Taken together, these results identify the caspase-8-mediated inflammatory pathway as a potential target for neuroprotection in glaucoma.

Molecular Pathogenesis of Ischemic and Hemorrhagic Strokes: Background and Therapeutic Approaches

Stroke represents one of the neurological diseases most responsible for death and permanent disability in the world. Different factors, such as thrombus, emboli and atherosclerosis, take part in the intricate pathophysiology of stroke. Comprehending the molecular processes involved in this mechanism is crucial to developing new, specific and efficient treatments. Some common mechanisms are excitotoxicity and calcium overload, oxidative stress and neuroinflammation. Furthermore, non-coding RNAs (ncRNAs) are critical in pathophysiology and recovery after cerebral ischemia. ncRNAs, particularly microRNAs, and long non-coding RNAs (lncRNAs) are essential for angiogenesis and neuroprotection, and they have been suggested to be therapeutic, diagnostic and prognostic tools in cerebrovascular diseases, including stroke. This review summarizes the intricate molecular mechanisms underlying ischemic and hemorrhagic stroke and delves into the function of miRNAs in the development of brain damage. Furthermore, we will analyze new perspectives on treatment based on molecular mechanisms in addition to traditional stroke therapies.

cFLIP in the molecular regulation of astroglia-driven neuroinflammation in experimental glaucoma

BACKGROUND

Recent experimental studies of neuroinflammation in glaucoma pointed to cFLIP as a molecular switch for cell fate decisions, mainly regulating cell type-specific caspase-8 functions in cell death and inflammation. This study aimed to determine the importance of cFLIP for regulating astroglia-driven neuroinflammation in experimental glaucoma by analyzing the outcomes of astroglia-targeted transgenic deletion of cFLIP or cFLIPL.

METHODS

Glaucoma was modeled by anterior chamber microbead injections to induce ocular hypertension in mouse lines with or without conditional deletion of cFLIP or cFLIPL in astroglia. Morphological analysis of astroglia responses assessed quantitative parameters in retinal whole mounts immunolabeled for GFAP and inflammatory molecules or assayed for TUNEL. The molecular analysis included 36-plexed immunoassays of the retina and optic nerve cytokines and chemokines, NanoString-based profiling of inflammation-related gene expression, and Western blot analysis of selected proteins in freshly isolated samples of astroglia.

RESULTS

Immunoassays and immunolabeling of retina and optic nerve tissues presented reduced production of various proinflammatory cytokines, including TNFα, in GFAP/cFLIP and GFAP/cFLIPL relative to controls at 12 weeks of ocular hypertension with no detectable alteration in TUNEL. Besides presenting a similar trend of the proinflammatory versus anti-inflammatory molecules displayed by immunoassays, NanoString-based molecular profiling detected downregulated NF-κB/RelA and upregulated RelB expression of astroglia in ocular hypertensive samples of GFAP/cFLIP compared to ocular hypertensive controls. Analysis of protein expression also revealed decreased phospho-RelA and increased phospho-RelB in parallel with an increase in caspase-8 cleavage products.

CONCLUSIONS

A prominent response limiting neuroinflammation in ocular hypertensive eyes with cFLIP-deletion in astroglia values the role of cFLIP in the molecular regulation of glia-driven neuroinflammation during glaucomatous neurodegeneration. The molecular responses accompanying the lessening of neurodegenerative inflammation also seem to maintain astroglia survival despite increased caspase-8 cleavage with cFLIP deletion. A transcriptional autoregulatory response, dampening RelA but boosting RelB for selective expression of NF-κB target genes, might reinforce cell survival in cFLIP-deleted astroglia.

Chronic pain exacerbates memory impairment and pathology of Aβ and tau by upregulating IL-1β and p-65 signaling in a mouse model of Alzheimer's disease

BACKGROUND

Chronic pain is linked to cognitive impairment; however, the underlying mechanisms remain unclear. In the present study, we examined these mechanisms in a well-established mouse model of Alzheimer's disease (AD).

METHODS

Neuropathic pain was modeled in 5-month-old transgenic APPswe/PS1dE9 (APP/PS1) mice by partial ligation of the sciatic nerve on the left side, and chronic inflammatory pain was modeled in another group of APP/PS1 mice by injecting them with complete Freund's adjuvant on the plantar surface of the left hind paw. Six weeks after molding, the animals were tested to assess pain threshold (von Frey filament), learning, memory (novel object recognition, Morris water maze, Y-maze, and passive avoidance), and depression-like symptoms (sucrose preference, tail suspension, and forced swimming). After behavioral testing, mice were sacrificed and the levels of p65, amyloid-β (residues 1-42) and phospho-tau in the hippocampus and cerebral cortex were assayed using western blotting, while interleukin (IL)-1β levels were measured by enzyme-linked immunosorbent assay.

RESULTS

Animals subjected to either type of chronic pain showed lower pain thresholds, more severe deficits in learning and memory, and stronger depression-like symptoms than the corresponding control animals. Either type of chronic pain was associated with upregulation of p65, amyloid-β (1-42), and IL-1β in the hippocampus and cerebral cortex, as well as higher levels of phosphorylated tau.

CONCLUSIONS

Chronic pain may exacerbate cognitive deficits and depression-like symptoms in APP/PS1 mice by worsening pathology related to amyloid-β and tau and by upregulating signaling involving IL-1β and p65.

Caspase-8 promotes NLRP3 inflammasome activation mediates eye development defects in zebrafish larvae exposed to perfulorooctane sulfonate (PFOS)

Epidemiological evidence showed that serum high perfluorooctane sulfonate (PFOS) levels are associated with multiple eye related diseases, but the potential underlying molecular mechanisms remain poorly understood. Zebrafish and photoreceptor cell (661w) models were used to investigate the molecular mechanism of PFOS induced eye development defects. Our results showed a novel molecular mechanism of PFOS-induced inflammation response-mediated photoreceptor cell death associated with eye development defects. Inhibition of Caspase-8 activation significantly decreased photoreceptor cell death in PFOS exposure. Mechanistically, Toll-like receptor 4 (TLR4) mediates activation of Caspase-8 promote activation of NLR family pyrin domain-containing 3 (NLRP3) inflammasome to elicit maturation of interleukin-1 beta (IL-1β) via Caspase-1 activation, facilitating photoreceptor cell inflammation damage in PFOS exposure. In addition, we also made a novel finding that Caspase-3 activation was increased via Caspase-8 activation and directly intensified cell death. Our results show the important role of Caspase-8 activation in PFOS induced eye development defects and highlight Caspase-8 mediated activation of the NLRP3 inflammation triggers activation of Caspase-1 and promote the maturation of IL-1β in retinal inflammatory injury.

Trimebutine prevents corneal inflammation in a rat alkali burn model

Alkaline burns to the cornea lead to loss of corneal transparency, which is essential for normal vision. We used a rat corneal alkaline burn model to investigate the effect of ophthalmic trimebutine solution on healing wounds caused by alkaline burns. Trimebutine, an inhibitor of the high-mobility group box 1-receptor for advanced glycation end products, when topically applied to the burned cornea, suppressed macrophage infiltration in the early phase and neutrophil infiltration in the late phase at the wound site. It also inhibited neovascularization and myofibroblast development in the late phase. Furthermore, trimebutine effectively inhibited interleukin-1β expression in the injured cornea. It reduced scar formation by decreasing the expression of type III collagen. These findings suggest that trimebutine may represent a novel therapeutic strategy for corneal wounds, not only through its anti-inflammatory effects but also by preventing neovascularization.

Regulated Necrosis in Glaucoma: Focus on Ferroptosis and Pyroptosis

Glaucoma is one of the most common causes of irreversible blindness worldwide. This neurodegenerative disease is characterized by progressive and irreversible damage to retinal ganglion cells (RGCs) and optic nerves, which can lead to permanent loss of peripheral and central vision. To date, maintaining long-term survival of RGCs using traditional treatments, such as medication and surgery, remains challenging, as these do not promote optic nerve regeneration. Therefore, it is of great clinical and social significance to investigate the mechanisms of optic nerve degeneration in depth and find reliable targets to provide pioneering methods for the prevention and treatment of glaucoma. Regulated necrosis is a form of genetically programmed cell death associated with the maintenance of homeostasis and disease progression in vivo. An increasing body of innovative evidence has recognized that aberrant activation of regulated necrosis pathways is a common feature in neurodegenerative diseases, such as Alzheimer's, Parkinson's, and glaucoma, resulting in unwanted loss of neuronal cells and function. Among them, ferroptosis and pyroptosis are newly discovered forms of regulated cell death actively involved in the pathophysiological processes of RGCs loss and optic nerve injury. This was shown by a series of in vivo and in vitro studies, and these mechanisms have been emerging as a key new area of scientific research in ophthalmic diseases. In this review, we focus on the molecular mechanisms of ferroptosis and pyroptosis and their regulatory roles in the pathogenesis of glaucoma, with the aim of exploring their implications as potential therapeutic targets and providing new perspectives for better clinical decision-making in glaucoma treatment.

Inhibition of HMGB1 improves experimental mice colitis by mediating NETs and macrophage polarization

OBJECTIVE

Inflammatory bowel disease (IBD) is listed by the World Health Organization as one of the modern intractable diseases. High mobility histone box 1 (HMGB1), originally described as a non-histone nucleoprotein involved in transcriptional regulation, was later identified as a pro-inflammatory cytokine that may contribute to the pathogenesis of inflammatory diseases such as IBD. Neutrophil extracellular traps (NETs) play an important role in the pathophysiology of IBD The aim of this study was to investigate the role of HMGB1 in experimental colitis mice and its potential mechanisms of action.

METHODS

We first constructed the experimental colitis mouse model. Intervention of mice by rhHMGB1 supplementation or HMGB1 inhibition. The pathological morphology of the colon was observed using HE staining. Apoptosis of colonic tissue intestinal epithelial cells was evaluated using Tunel assay. The expression of HMGB1, ZO-1 and occludin in colon tissue was detected by immunohistochemistry, ELISA and western-blot. We also assessed the effects of HMGB1 on colonic injury, NETs content, macrophage polarization and inflammatory cells in mice. The regulatory effect of HMGB1 inhibition on NETs was assessed by combining DNase I.

RESULTS

Inhibition of HMGB1 significantly reduced the inflammatory model in experimental colitis mice, as evidenced by reduced body weight, increased colonic length, reduced DAI scores and apoptosis, reduced inflammatory response, and improved colonic histopathological morphology and intestinal mucosal barrier function. Meanwhile, inhibition of HMGB1 was able to reduce the expression of CD86, citH3 and MPO and increase the expression of CD206 in the colonic tissue of mice. In addition, DNase I intervention was also able to improve colonic inflammation in mice. And the best effect was observed when DNase I and inhibition of HMGB1 were intervened together.

CONCLUSION

Inhibition of HMGB1 ameliorates IBD by mediating NETs and macrophage polarization.

Tomato SlMAPK3 Modulates Cold Resistance by Regulating the Synthesis of Raffinose and the Expression of SlWRKY46

Mitogen-activated protein kinase (MAPK) cascades and raffinose have been observed to increase in plants exposed to cold. However, it remains elusive whether and how MAPK regulates raffinose synthesis under cold stress. Here, overexpression of SlMAPK3 promoted the accumulation of galactinol and raffinose under cold stress, while CRISPR/Cas9-mediated mutants showed the opposite results. Moreover, SlMAPK3 promoted the expression of SlWRKY46 at low temperatures and interacted with SlWRKY46 protein. Overexpression of SlWRKY46 enhanced cold resistance. Furthermore, SlWRKY46 directly bound to the promoter of SlGols1 to enhance its expression and promoted the accumulation of raffinose. Virus-induced gene-silencing (VIGS)-mediated knockdown of SlGols1 remarkably elevated cold sensitivity and reduced raffinose content. Meanwhile, exogenous supplementation of raffinose could improve the cold tolerance of tomato plants. Thus, our data indicates that SlMAPK3 modulates cold resistance by regulating raffinose content and SlWRKY46 expression. SlWRKY46 also promotes the accumulation of raffinose by inducing the expression of SlGols1.

Expression and correlation of the NOD-like receptor family, pyrin domain-containing 3 inflammasome and the silent information regulator 1 in patients with drug-resistant epilepsy

BACKGROUND

The NOD-like receptor family, pyrin domain-containing 3 (NLRP3) inflammatory pathway is implicated in the development of epilepsy and can be suppressed by the activation of the silent information regulator 1 (SIRT1). However, the expression and correlation of the NLRP3 pathway and SIRT1 in drug-resistant epilepsy (DRE) remain unknown.

METHODS

This study evaluated the histopathology of the cerebral cortex from nine patients with DRE and eight patients with cavernous haemangioma undergoing surgical treatment. It analysed the expression of the NLRP3, interleukin-1β (IL-1β), caspase-1 and SIRT1 using immunohistochemistry. Additionally, the contents of NLRP3, caspase-1, IL-1β and SIRT1 in the serum samples of the included study participants were determined using ELISA method. The correlation between the NLRP3 pathway and the SIRT1 was assessed using Spearman's correlation analysis.

RESULTS

The expression of NLRP3, caspase-1 and IL-1β in the cerebral cortex of patients with DRE was elevated, with the NLRP3 expression being negatively correlated with the SIRT1 expression. Furthermore, IL-1β in serum was upregulated in patients with DRE. The correlation between the content of serum SIRT1 and NLRP3, caspase-1 and IL-1β in patients with DRE was not significant. Notably, serum caspase-1 levels were obviously higher in patients with bilateral hippocampal sclerosis than in patients with unilateral hippocampal sclerosis.

CONCLUSIONS

The current results indicate that the expression of the NLRP3/caspase-1/IL-1β pathway is significantly upregulated in patients with DRE and that it is partially correlated with the SIRT1 expression. This study is important for understanding the pathophysiology of DRE and developing new treatment strategies for it.

Hypoxic Preconditioning Attenuates Neuroinflammation via Inhibiting NF-κB/NLRP3 Axis Mediated by p-MLKL after Transient Global Cerebral Ischemia

Hypoxic preconditioning (HPC) has been reported to alleviate neuronal damage and microglial activation in hippocampal CA1 after transient global cerebral ischemia (tGCI). However, the molecular mechanism is unclear. Recent studies identified that nuclear factor-kappa-B (NF-κB)/oligomerization domain-like receptors protein (NLRP) 3 inflammasome pathway is mainly involved in the activation of microglia and that phosphorylated (p)-mixed lineage kinase domain-like (MLKL) is related to the regulation of NF-κB/NLRP3 axis. Hence, in this study, we set out to investigate whether HPC attenuates neuronal damage and microglial activation through inhibiting NF-κB/NLRP3 axis mediated by p-MLKL after tGCI in CA1 of male rats. We found that HPC decreased NLRP3 inflammasome in microglia and inhibited M1 polarization of microglia in CA1 after tGCI. Mechanistically, HPC inhibited the activation of NF-κB signaling pathway and reduced the mRNA and protein levels of NLRP3 inflammasome after tGCI. Additionally, the knockdown of p-MLKL by short hairpin RNA (shRNA) administration inhibited the activation of the NF-κB signaling pathway and reduced the formation of NLRP3 inflammasome, thus attenuating M1 polarization of microglia and decreasing the release of interleukin 1 beta (IL-1β) and necrosis factor alpha (TNF-α) in CA1 post ischemia. We consider that p-MLKL in microglia may be derived from necroptotic neurons after tGCI. In conclusion, the new finding in this study is that HPC-induced neuroprotection against tGCI through inhibiting NF-κB/NLRP3 pathway mediated by p-MLKL.

Increased expression of NLRP3 associated with elevated levels of HMGB1 in children with febrile seizures: a case-control study

BACKGROUND

High mobility group box-1 (HMGB1) is an endogenous danger signal that mediates activation of the innate immune response including NLR pyrin domain containing 3 (NLRP3) inflammasome activation and proinflammatory cytokine release. Although HMGB1 and NLRP3 have been implicated in the pathophysiology of seizures, the correlation between HMGB1 and NLRP3 expression has not been determined in children with febrile seizures (FS). To explore the relationship between extra-cellular HMGB1 and NLRP3 in children with FS, we analyzed serum HMGB1, NLRP3, caspase-1, and proinflammatory cytokines in patients with FS.

METHODS

Thirty children with FS and thirty age-matched febrile controls were included in this study. Blood was obtained from the children with FS within 1 h of the time of the seizure; subsequently, the serum contents of HMGB1, NLRP3, caspase-1, interleukin (IL)-1β, interleukin (IL)-6, and tumour necrosis factor-α (TNF-α) were determined by enzyme-linked immunosorbent assay. The Mann‒Whitney U test was used to compare serum cytokine levels between FS patients and controls. Spearman's rank correlation coefficient was calculated to detect significant correlations between cytokine levels.

RESULTS

Serum levels of HMGB1, NLRP3, caspase-1, IL-1β, IL-6, and TNF-α were significantly higher in FS patients than in febrile controls (p < 0.05). Serum levels of HMGB1 were significantly correlated with levels of NLRP3 and caspase-1 (both, p < 0.05). Serum levels of caspase-1 were significantly correlated with levels of IL-1β (p < 0.05). Serum levels of IL-1β were significantly correlated with levels of IL-6 and TNF-α (p < 0.05).

CONCLUSIONS

HMGB1 is up-regulated in the peripheral serum of FS patients, which may be responsible, at least in part, for the increased expression of NLRP3 and Caspase-1. Increased expression of caspase-1 was significantly associated with elevated serum levels of IL-1β. Given that activated Caspase-1 directly regulates the expression of mature IL-1β and positively correlates with activation of the NLRP3 inflammasome, our data suggest that increased levels of peripheral HMGB1 possibly mediate IL-1β secretion through the activation of the NLRP3 inflammasome in children with FS. Thus, both HMGB1 and NLRP3 might be potential targets for preventing or limiting FS.

CX3CL1/CX3CR1 Signaling Mediated Neuroglia Activation Is Implicated in the Retinal Degeneration: A Potential Therapeutic Target to Prevent Photoreceptor Death

Purpose

Retinal degeneration (RD) is a large cluster of retinopathies that is characterized by the progressive photoreceptor death and visual impairments. CX3CL1/CX3CR1 signaling has been documented to mediate the microglia activation and gliosis reaction during neurodegeneration. We intend to verify whether the CX3CL1/CX3CR1 signaling is involved in the RD pathology.

Methods

A pharmacologically induced RD mice model was established. AZD8797, a CX3CR1 antagonist, was injected into the vitreous cavity of an RD model to modulate the neuroglia activation. Then, the experimental animals were subjected to functional, morphological, and behavioral analysis.

Results

The CX3CL1/CX3CR1 signaling mediated neuroglia activation was implicated in the photoreceptor demise of an RD model. Intravitreal injection of AZD8797 preserved the retinal structure and enhanced the photoreceptor survival through inhibiting the CX3CL1/CX3CR1 expressions. Fundus photography showed that the distribution of retinal vessel was clear, and the severity of lesions was alleviated by AZD8797. In particular, these morphological benefits could be translated into remarkable functional improvements, as evidenced by the behavioral test and electroretinogram (mf-ERG) examination. A mechanism study showed that AZD8797 mitigated the microglia activation and migration in the degenerative retinas. The Müller cell hyper-reaction and secondary gliosis response were also suppressed by AZD8797.

Conclusions

The neuroinflammation is implicated in the photoreceptor loss of RD pathology. Targeting the CX3CL1/CX3CR1 signaling may serve as an effective therapeutic strategy. Future refinements of these findings may cast light into the discovery of new medications for RD.

siRNA Mediated Downregulation of RhoA Expression Reduces Oxidative Induced Apoptosis in Retinal Ganglion Cells

BACKGROUNDS

Glaucoma is the second leading cause of blindness. Apoptosis of retinal ganglion cells (RGCs) is an important mechanism of glaucomatous optic injury. Rho kinase expression is significantly increased in apoptotic RGCs. This study aimed to investigate the role of RhoA, a Rho GTPase, on the survival of RGCs and further to explore its potential therapeutic applications.

METHODS

RGCs were treated with siRhoA for 24 hours in vitro. Knockdown of RhoA was confirmed with quantitative RT-PCR. Oxidative stress was induced by treating the RGCs with 200 μM of H2O2 for 1 hour, and apoptosis of RGCs was quantified with TUNEL assay in situ, and with flow cytometry. The mRNA expression levels of RhoA, Nogo receptor, caspase 3 and Bcl-2 were evaluated by quantitative RT-PCR, and the protein levels of RhoA, ROCK1, ROCK2, Nogo receptor, caspase 3 and Bcl-2 were evaluated by Western blot. We found siRhoA treatment efficiently downregulated the expression of RhoA in RGCs and protected against H2O2-induced injury in RGCs in vitro. Apoptosis of RGC cells under oxidative stress was quantified in situ using TUNEL assay and confirmed with flow cytometry (FCM).

RESULTS

With the knockdown of RhoA, the expression of ROCK1, ROCK2, Nogo Receptor, Casepase-3 were decreased, while the expression of Bcl-2 was increased in both mRNA and protein level. Our data indicated that siRhoA prevented H2O2-induced apoptosis in RGC cells by modulating the RhoA/ROCK pathway.

CONCLUSION

The results suggested that siRhoA may exert potentially effective neuroprotection for RGCs by reducing injury.

High-mobility group box 1 emerges as a therapeutic target for asthma

High-mobility group box 1 (HMGB1) is a highly conserved nonhistone nuclear protein found in the calf thymus and participates in a variety of intracellular processes such as DNA transcription, replication and repair. In the cytoplasm, HMGB1 promotes mitochondrial autophagy and is involved in in cellular stress response. Once released into the extracellular, HMGB1 becomes an inflammatory factor that triggers inflammatory responses and a variety of immune responses. In addition, HMGB1 binding with the corresponding receptor can activate the downstream substrate to carry out several biological effects. Meanwhile, HMGB1 is involved in various signaling pathways, such as the HMGB1/RAGE pathway, HMGB1/NF-κB pathway, and HMGB1/JAK/STAT pathway, which ultimately promote inflammation. Moreover, HMGB1 may be involved in the pathogenesis of asthma by regulating downstream signaling pathways through corresponding receptors and mediates a number of signaling pathways in asthma, such as HMGB1/TLR4/NF-κB, HMGB1/RAGE, HMGB1/TGF-β, and so forth. Accordingly, HMGB1 emerges as a therapeutic target for asthma.

The Inflammasome-Dependent Dysfunction and Death of Retinal Ganglion Cells after Repetitive Intraocular Pressure Spikes

The dysfunction and selective loss of retinal ganglion cells (RGCs) is a known cause of vision loss in glaucoma and other neuropathies, where ocular hypertension (OHT) is the major risk factor. We investigated the impact of transient non-ischemic OHT spikes (spOHT) on RGC function and viability in vivo to identify cellular pathways linking low-grade repetitive mechanical stress to RGC pathology. We found that repetitive spOHT had an unexpectedly high impact on intraocular homeostasis and RGC viability, while exposure to steady OHT (stOHT) of a similar intensity and duration failed to induce pathology. The repetitive spOHT induced the rapid activation of the inflammasome, marked by the upregulation of NLRP1, NLRP3, AIM2, caspases -1, -3/7, -8, and Gasdermin D (GSDMD), and the release of interleukin-1β (IL-1β) and other cytokines into the vitreous. Similar effects were also detected after 5 weeks of exposure to chronic OHT in an induced glaucoma model. The onset of these immune responses in both spOHT and glaucoma models preceded a 50% deficit in pattern electroretinogram (PERG) amplitude and a significant loss of RGCs 7 days post-injury. The inactivation of inflammasome complexes in Nlrp1-/-, Casp1-/-, and GsdmD-/- knockout animals significantly suppressed the spOHT-induced inflammatory response and protected RGCs. Our results demonstrate that mechanical stress produced by acute repetitive spOHT or chronic OHT is mechanistically linked to inflammasome activation, which leads to RGC dysfunction and death.

HMGB1 inhibition reduces TDI-induced occupational asthma through ROS/AMPK/autophagy pathway

Exposure to toluene diisocyanate (TDI) can cause pulmonary diseases such as asthma. Inhibition of high mobility group box 1 protein (HMGB1) has been found to be protective against the toxic effects of TDI on human bronchial epithelial (HBE) cells. Here, we evaluated the in vivo positive roles of HMGB1 in the TDI-caused asthma mice and explored its underlying mechanisms in HBE cells. We found that suppression of HMGB1 obviously alleviated airway inflammation, airway hyperresponsiveness, and airway remodeling in the lung tissue of the asthma mice. The in vitro results showed that inhibition of HMGB1 ameliorated TDI-induced reactive oxygen species (ROS) release, inflammatory response, and activation of autophagy in HBE cells. At the molecular level, inhibition of HMGB1 decreased the expressions of HMGB1, Toll-like receptor 4, Vimentin and matrix metalloproteinase-9 proteins, activated NF-κB and NOD-like receptor protein 3 (NLRP3) inflammasome, and increased E-cadherin expression. Importantly, activation of autophagy could lead to the overactivation of NLRP3 inflammasome in TDI-induced asthma. These results suggest that inhibition of HMGB1 can alleviate TDI-induced asthma through ROS/AMPK/autophagy pathways, which may provide valuable evidence for the pathogenesis and therapeutic targets of TDI-induced asthma.

Endoplasmic reticulum stress: molecular mechanism and therapeutic targets

The endoplasmic reticulum (ER) functions as a quality-control organelle for protein homeostasis, or "proteostasis". The protein quality control systems involve ER-associated degradation, protein chaperons, and autophagy. ER stress is activated when proteostasis is broken with an accumulation of misfolded and unfolded proteins in the ER. ER stress activates an adaptive unfolded protein response to restore proteostasis by initiating protein kinase R-like ER kinase, activating transcription factor 6, and inositol requiring enzyme 1. ER stress is multifaceted, and acts on aspects at the epigenetic level, including transcription and protein processing. Accumulated data indicates its key role in protein homeostasis and other diverse functions involved in various ocular diseases, such as glaucoma, diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, achromatopsia, cataracts, ocular tumors, ocular surface diseases, and myopia. This review summarizes the molecular mechanisms underlying the aforementioned ocular diseases from an ER stress perspective. Drugs (chemicals, neurotrophic factors, and nanoparticles), gene therapy, and stem cell therapy are used to treat ocular diseases by alleviating ER stress. We delineate the advancement of therapy targeting ER stress to provide new treatment strategies for ocular diseases.

Inhibition of NOX4 with GLX351322 alleviates acute ocular hypertension-induced retinal inflammation and injury by suppressing ROS mediated redox-sensitive factors activation

Reactive oxygen species (ROS) overproduction plays an essential role in the etiology of ischemic/hypoxic retinopathy caused by acute glaucoma. NADPH oxidase (NOX) 4 was discovered as one of the main sources of ROS in glaucoma. However, the role and potential mechanisms of NOX4 in acute glaucoma have not been fully elucidated. Therefore, the current study aims to investigate the NOX4 inhibitor GLX351322 that targets NOX4 inhibition in acute ocular hypertension (AOH)-induced retinal ischemia/hypoxia injury in mice. Herein, NOX4 was highly expressed in AOH retinas, particularly the retinal ganglion cell layer (GCL). Importantly, the NOX4 inhibitor GLX351322 reduced ROS overproduction, inhibited inflammatory factor release, suppressed glial cell activation and hyperplasia, inhibited leukocyte infiltration, reduced retinal cell senescence and apoptosis in damaged areas, reduced retinal degeneration and improved retinal function. This neuroprotective effect is at least partially associated with mediated redox-sensitive factor (HIF-1α, NF-κB, and MAPKs) pathways by NOX4-derived ROS overproduction. These results suggest that inhibition of NOX4 with GLX351322 attenuated AOH-induced retinal inflammation, cellular senescence, and apoptosis by inhibiting the activation of the redox-sensitive factor pathway mediated by ROS overproduction, thereby protecting retinal structure and function. Targeted inhibition of NOX4 is expected to be a new idea in the treatment of acute glaucoma.

Huangqi Guizhi Wuwu decoction promotes M2 microglia polarization and synaptic plasticity via Sirt1/NF-κB/NLRP3 pathway in MCAO rats

Huangqi Guizhi Wuwu decoction (HGWD) has been demonstrated to ameliorate cerebral ischemia-reperfusion injury in clinical application. Nevertheless, the exact mechanisms of HGWD have not been conclusively elucidated. This study aimed to investigate the potential role and mechanism of HGWD on neurological deficits in a rat model of middle cerebral artery occlusion (MCAO). Our results showed that HGWD significantly alleviated neurological deficits in MCAO rats, evidenced by high mNSS score, reduced cerebral infarction area, and improved brain pathological injury. Besides, HGWD reduced the levels of TNF-α, IL-1β, IL-6, SOD, MDA and GSH in the brain tissue. Further study suggested that HGWD promoted microglia polarization towards M2 by inhibiting M1 activation (Iba1+/CD16+, iNOS) and enhancing M2 activation (Iba1+/CD206+, Arg-1). Additionally, HGWD increased dendritic spine density and enhanced levels of synapse marker proteins (PSD95, Synapsin I). HGWD also up-regulated Sirt1 expression while inhibited p-NF-κB, NLRP3, ASC, and cleaved caspase-1 level in the hippocampus of MCAO rats. Sirt1 specific inhibitor EX527 notably weakened the neuroprotective efficacy of HGWD against cerebral ischemia, and significantly abolished its modulation on microglia polarization and synaptic plasticity in vivo. Collectively, our findings suggested that HGWD ameliorated neuronal injury in ischemic stroke by modulating M2 microglia polarization and synaptic plasticity, at least partially, via regulating Sirt1/NF-κB/NLRP3 pathway, further supporting HGWD as a potential therapy for neuroprotection after ischemic stroke.

Bibliometric and visual analysis of diabetes mellitus and pyroptosis from 2011 to 2022

OBJECTIVE

To visualize and analyze the published literature on diabetes mellitus and pyroptosis based on a bibliometric approach, so as to provide a comprehensive picture of the hot research directions and dynamic progress in this field.

METHODS

This study was based on the web of science core collection database to conduct a comprehensive search of the published literature in the field of diabetes mellitus and Pyroptosis from January 1985 to August 2022, including the published research literature in this field, as well as a visual analysis of the number of citations, year of publication, journal, author, research institution, country, and research topic.

RESULTS

A total of 139 literature on research related to diabetes mellitus and cellular scorch from 2011 to 2022 were retrieved, with a total of 3009 citations and a maximum of 255 citations for a single article, which had a first author Schmid-Burgk, JL The first author of this article is from Germany; among 20 publishing countries, China leads with 100 articles; among 222 publishing institutions, Harbin Medical University leads with 18 articles and 184 citations; among 980 authors, Chen, X from China tops the list of high-impact authors with 5 articles and 29 citations. Among the 98 journals, "CELL DEATH DISEASE" ranked first in both volume and high-impact journals with 4 articles and 29 citations. Among 349 keywords, "pyroptosis" ranked first with a cumulative frequency of 65 times. The cluster analysis was divided into three categories, chronic complications of diabetes mellitus and pyroptosis (67 articles), diabetes mellitus and pyroptosis (60 articles), and diabetes mellitus combined with other diseases and pyroptosis (12 articles), and the number of articles related to diabetes mellitus and its chronic complications increased rapidly from 2019, among which, diabetic cardiomyopathy (27 articles) had the highest number of articles.

CONCLUSIONS

Based on a comprehensive analysis of published literature in the field of diabetes mellitus and pyroptosis from 2011 to 2022, this study achieved a visual analysis of studies with significant and outstanding contributions to the field, thus framing a picture showing the development and changes in the field. At the same time, this study provides research information and direction for clinicians and investigators to conduct diabetes mellitus and pyroptosis-related research in the future.

HMGB1 in depression: An overview of microglial HMBG1 in the pathogenesis of depression

Depression is a prevalent psychiatric disorder with elusive pathogenesis. Studies have proposed that enhancement and persistence of aseptic inflammation in the central nervous system (CNS) may be closely associated with the development of depressive disorder. High mobility group box 1 (HMGB1) has obtained significant attention as an evoking and regulating factor in various inflammation-related diseases. It is a non-histone DNA-binding protein that can be released as a pro-inflammatory cytokine by glial cells and neurons in the CNS. Microglia, as the immune cell of the brain, interacts with HMGB1 and induces neuroinflammation and neurodegeneration in the CNS. Therefore, in the current review, we aim to investigate the role of microglial HMGB1 in the pathogenetic process of depression.

Apigenin attenuates atherosclerosis and non-alcoholic fatty liver disease through inhibition of NLRP3 inflammasome in mice

Apigenin (APN), a flavone found in several plant foods with various biological properties such as anti-obesity, anti-inflammation and other abilities, alleviates atherosclerosis and non-alcoholic fatty liver disease (NAFLD) induced by a high fat diet (HFD) in mice. However, the underlying mechanisms have not been fully understood. In this study, we investigated the role of NLRP3 in anti-atherosclerosis and anti-NAFLD effect of APN in mouse models with NLRP3 deficiency. Atherosclerosis and NAFLD models were established by treatment of low density lipoprotein receptor-deficient (Ldlr^-/-) mice and NLRP3^-/- Ldlr^-/- mice with a HFD diet (20% fat and 0.5% cholesterol) with or without APN. En face lipid accumulation analysis, plasma lipid levels, hepatic lipid accumulation and inflammation were analyzed and quantified. For in vitro experiments, HepG2 cells were stimulated by LPS plus oleic acid (OA) in the absence or presence of APN (50 μM). Lipid accumulation and the effect of APN on the NLRP3/NF-κB signaling pathway were investigated. APN administration partly reversed atherosclerosis and hepatic lipid accumulation, and decreased body weight and plasma lipid levels in Ldlr^-/- mice when fed a HFD. Compared with Ldlr^-/- mice, NLRP3^-/- Ldlr^-/- mice showed more severe atherosclerosis and hepatic lipid accumulation. Treating the HepG2 cells with APN reduced lipid accumulation. APN also inhibited activation of the NLRP3/ NF-κB signaling pathway stimulated by OA together with LPS. Our results indicate that APN supplementation prevents atherosclerosis and NAFLD via NLRP3 inhibition in mice, and suggest that APN might be a potential therapeutic agent for the prevention of atherosclerosis and NAFLD.

NLRP3 Inflammasome’s Activation in Acute and Chronic Brain Diseases—An Update on Pathogenetic Mechanisms and Therapeutic Perspectives with Respect to Other Inflammasomes

Increasingly prevalent acute and chronic human brain diseases are scourges for the elderly. Besides the lack of therapies, these ailments share a neuroinflammation that is triggered/sustained by different innate immunity-related protein oligomers called inflammasomes. Relevant neuroinflammation players such as microglia/monocytes typically exhibit a strong NLRP3 inflammasome activation. Hence the idea that NLRP3 suppression might solve neurodegenerative ailments. Here we review the recent Literature about this topic. First, we update conditions and mechanisms, including RNAs, extracellular vesicles/exosomes, endogenous compounds, and ethnic/pharmacological agents/extracts regulating NLRP3 function. Second, we pinpoint NLRP3-activating mechanisms and known NLRP3 inhibition effects in acute (ischemia, stroke, hemorrhage), chronic (Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, MS, ALS), and virus-induced (Zika, SARS-CoV-2, and others) human brain diseases. The available data show that (i) disease-specific divergent mechanisms activate the (mainly animal) brains NLRP3; (ii) no evidence proves that NLRP3 inhibition modifies human brain diseases (yet ad hoc trials are ongoing); and (iii) no findings exclude that concurrently activated other-than-NLRP3 inflammasomes might functionally replace the inhibited NLRP3. Finally, we highlight that among the causes of the persistent lack of therapies are the species difference problem in disease models and a preference for symptomatic over etiologic therapeutic approaches. Therefore, we posit that human neural cell-based disease models could drive etiological, pathogenetic, and therapeutic advances, including NLRP3’s and other inflammasomes’ regulation, while minimizing failure risks in candidate drug trials.

Exosomal Lnc NEAT1 from endothelial cells promote bone regeneration by regulating macrophage polarization via DDX3X/NLRP3 axis

BACKGROUND

Bone regeneration is a complex procedure that involves an interaction between osteogenesis and inflammation. Macrophages in the microenvironment are instrumental in bone metabolism. Amount evidence have revealed that exosomes transmitting lncRNA is crucial nanocarriers for cellular interactions in various biotic procedures, especially, osteogenesis. However, the underlying mechanisms of the regulatory relationship between the exosomes and macrophages are awaiting clarification. In the present time study, we aimed to explore the roles of human umbilical vein endothelial cells (HUVECs)-derived exosomes carrying nuclear enrichment enriched transcript 1 (NEAT1) in the osteogenesis mediated by M2 polarized macrophages and elucidate the underlying mechanisms.

RESULTS

We demonstrated HUVECs-derived exosomes expressing NEAT1 significantly enhanced M2 polarization and attenuated LPS-induced inflammation in vitro. Besides, the conditioned medium from macrophages induced by the exosomes indirectly facilitated the migration and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Mechanically, Exos carrying NEAT1 decreased remarkably both expression of dead-box helicase 3X-linked (DDX3X) and nod-like receptor protein 3 (NLRP3). The level of NLRP3 protein increased significantly after RAW264.7 cells transfected with DDX3X overexpression plasmid. Additionally, the knockdown of NEAT1 in exosomes partially counteracted the aforementioned effect of Exos. The results of air pouch rat model demonstrated that HUVECs-derived exosomes increased anti-inflammatory cytokines (IL-10) and decreased pro-inflammatory cytokines (IL-1β and IL-6) significantly in vivo, contributing to amelioration of LPS-induced inflammation. Afterwards, we further confirmed that the HUVECs-derived exosomes encapsulated in alginate/gelatin methacrylate (GelMA) interpenetrating polymer network (IPN) hydrogels could promote the bone regeneration, facilitate the angiogenesis, increase the infiltration of M2 polarized macrophages as well as decrease NLRP3 expression in the rat calvarial defect model.

CONCLUSIONS

HUVECs-derived exosomes enable transmitting NEAT1 to alleviate inflammation by inducing M2 polarization of macrophages through DDX3X/NLRP3 regulatory axis, which finally contributes to osteogenesis with the aid of alginate/GelMA IPN hydrogels in vivo. Thus, our study provides insights in bone healing with the aid of HUVECs-derived exosomes-encapsulated composite hydrogels, which exhibited potential towards the use of bone tissue engineering in the foreseeable future.

DTX3L induced NLRP3 ubiquitination inhibit R28 cell pyroptosis in OGD/R injury

Ischemia/reperfusion (I/R) injury is one of the most common etiologies in many diseases. Retinal I/R leads to cytokine storm, resulting in tissue damage and cell death. Pyroptosis, a novel type of regulated cell death, occurs after cellular I/R injury. In this study, we established an oxygen glucose deprivation (OGD/R) cellular model (R28) to simulate retinal I/R injury. We conducted an LDH assay, and EthD-III and PI staining procedures to confirm pyroptosis. Mass spectrometry and bioinformatics analysis were used to identify the possible proteins interacting with NLRP3. Co-IP and various molecular biology techniques were used to investigate the possible modes regulating NLRP3 by DTX3L. EthD-III, PI staining and LDH assays demonstrated pyroptosis induced by OGD/R injury, mediated via NLRP3 pathway. Mass spectrometry and bioinformatics analysis screened out three candidate proteins interacting with NLRP3, and further Co-IP experiment indicated that DTX-3L may interact with NLRP3 to regulate its protein levels after injury. Co-IP experiments and various molecular biology methods demonstrated that DTX3L ubiquitinates NLRP3 resulting in pyroptosis after R28 OGD/R injury. Further, NLRP3 LRR and DTX3L RING domains interact with each other. Our study demonstrated that DTX3L may ubiquitinate NLRP3 to regulate OGD/R-induced pyroptosis globally in R28 cells.

Integrative applications of network pharmacology and molecular docking: An herbal formula ameliorates H9c2 cells injury through pyroptosis

Background

QiShen YiQi pills (QSYQ) is a Traditional Chinese Medicine (TCM) formula, which has a significant effect on the treatment of patients with myocardial infarction (MI) in clinical practice. However, the molecular mechanism of QSYQ regulation pyroptosis after MI is still not fully known. Hence, this study was designed to reveal the mechanism of the active ingredient in QSYQ.

Methods

Integrated approach of network pharmacology and molecular docking, were conducted to screen active components and corresponding common target genes of QSYQ in intervening pyroptosis after MI. Subsequently, STRING and Cytoscape were applied to construct a PPI network, and obtain candidate active compounds. Molecular docking was performed to verify the binding ability of candidate components to pyroptosis proteins and oxygen-glucose deprivation (OGD) induced cardiomyocytes injuries were applied to explore the protective effect and mechanism of the candidate drug.

Results

Two drug-likeness compounds were preliminarily selected, and the binding capacity between Ginsenoside Rh2 (Rh2) and key target High Mobility Group Box 1 (HMGB1)was validated in the form of hydrogen bonding. 2 μM Rh2 prevented OGD-induced H9c2 death and reduced IL-18 and IL-1β levels, possibly by decreasing the activation of the NLRP3 inflammasome, inhibiting the expression of p12-caspase1, and attenuating the level of pyroptosis executive protein GSDMD-N.

Conclusions

We propose that Rh2 of QSYQ can protect myocardial cells partially by ameliorating pyroptosis, which seems to have a new insight regarding the therapeutic potential for MI.

RAGE contributes to allergen driven severe neutrophilic airway inflammation via NLRP3 inflammasome activation in mice

Background

Asthma is a major public healthcare burden, affecting over 300 million people worldwide. While there has been great progress in the treatment of asthma, subsets of patients who present with airway neutrophilia, often have more severe disease, and tend to be resistant to conventional corticosteroid treatments. The receptor for advanced glycation endproducts (RAGE) plays a central role in the pathogenesis of eosinophilic asthma, however, it's role in neutrophilic asthma remains largely uninvestigated.

Methods

A mouse model of severe steroid resistant neutrophilic airway disease (SSRNAD) using the common fungal allergen Alternaria alternata (AA) was employed to evaluate the effects of genetic ablation of RAGE and pharmacological inhibition of the NLRP3 inflammasome on neutrophilic airway inflammation.

Results

AA exposure induced robust neutrophil-dominant airway inflammation and increased BALF levels of Th1/Th17 cytokines in wild-type mice, which was significantly reduced in RAGE^-/- mice. Serum levels of IgE and IgG1 were increased similarly in both wild-type and RAGE^-/- mice. Pharmacological inhibition of NLRP3 blocked the effects of AA exposure and NLRP3 inflammasome activation was RAGE-dependent. Neutrophil extracellular traps were elevated in the BALF of wild-type but not RAGE^-/- mice and an atypical population of SiglecF+ neutrophils were identified in the BALF. Lastly, time-course studies found that RAGE expression promoted sustained neutrophil accumulation in the BALF of mice in response to AA.

Danger signals released during cold ischemia storage activate NLRP3 inflammasome in myeloid cells and influence early allograft function in liver transplantation

BACKGROUND

Innate immunity plays a fundamental role in solid organ transplantation. Myeloid cells can sense danger signals or DAMPs released after tissue or cell damage, such as during ischemia processes. This study aimed to identify DAMPs released during cold ischemia storage of human liver and analyze their ability to activate the inflammasome in myeloid cells and the possible implications in terms of short-term outcomes of liver transplantation.

METHODS

79 samples of organ preservation solution (OPS) from 79 deceased donors were collected after cold static storage. We used different analytical methods to measure DAMPs in these end-ischemic OPS (eiOPS) samples. We also used eiOPS in the human macrophage THP-1 cell line and primary monocyte cultures to study inflammasome activation.

FINDINGS

Different DAMPs were identified in eiOPS, several of which induced both priming and activation of the NLRP3 inflammasome in human myeloid cells. Cold ischemia time and donation after circulatory death negatively influenced the DAMP signature. Moreover, the presence of oligomeric inflammasomes and interleukin-18 in eiOPS correlated with early allograft dysfunction in liver transplant patients.

INTERPRETATION

DAMPs released during cold ischemia storage prime and activate the NLRP3 inflammasome in liver macrophages after transplantation, inducing a pro-inflammatory environment that will complicate the outcome of the graft. The use of pharmacological blockers targeting DAMPs or the NLRP3 inflammasome in liver ischemia during static cold storage or through extracorporeal organ support could be a suitable strategy to increase the success of liver transplantation.

FUNDING

Fundación Mutua Madrileña and Instituto de Salud Carlos III, Madrid, Spain.

Gastroprotective effects of water extract of domesticated Amauroderma rugosum against several gastric ulcer models in rats

CONTEXT

Amauroderma rugosum (Blume & T. Nees) Torrend (Ganodermataceae) is an edible mushroom with medicinal properties. However, the effects of A. rugosum on gastric ulcer remain unclear.

OBJECTIVE

To investigate the gastroprotective efficacy of water extract of A. rugosum (WEA) on gastric ulcer.

MATERIALS AND METHODS

Sprague-Dawley rats were randomly grouped as control, model, lansoprazole and 200, 100 and 50 mg/kg of WEA. After pre-treatment for seven days, ethanol- and indomethacin-induced gastric ulcer models were established. The gastric ulcer and histopathology were investigated. Enzyme-linked immunosorbent assay (ELISA), quantitative polymerase chain reaction (Q-PCR) and Western blot assays were conducted to explore the potential anti-inflammatory effect and mechanism of WEA. Additionally, the pyloric ligation model was used to explore the influence of WEA on gastric acid and mucus.

RESULTS

Pre-treatment with WEA (200, 100 and 50 mg/kg) effectively reduced ulcerous area in both ethanol-induced (71%, 88% and 71%) and indomethacin-induced (77%, 65% and 86%) gastric ulcer model. The gastric levels of tumour necrosis factor-alpha (TNF-α) (34% and 50 mg/kg), interleukin-6 (IL-6) (32% and 100 mg/kg) and interleukin-1β (IL-1β) (36%, 45% and 41%) were reduced significantly (p < 0.05) by WEA. Serum nitric oxide was decreased significantly (p < 0.05) at 200 and 50 mg/kg and PGE2 concentration was increased remarkably (p < 0.05) at 100 mg/kg. Gene expression of inflammasome Nlrp3, and the nuclear translocation of nuclear factor-κB (NF-κB) P65 were significantly decreased by WEA pre-treatment. However, the pH of gastric acid and secretion of mucus did not show any significant change.

CONCLUSIONS

The gastroprotective effect of WEA on gastric damage is attributed to anti-inflammation through the inhibition on NF-κB P65 nuclear migration and Nlrp3 gene expression.

Linear ubiquitination of LKB1 activates AMPK pathway to inhibit NLRP3 inflammasome response and reduce chondrocyte pyroptosis in osteoarthritis

Background

Osteoarthritis (OA) is the most common chronic disease. It is characterized by high levels of clinical heterogeneity and low inflammation. Therefore, elucidation of the mechanisms that regulate gene expression is critical for developing effective OA therapies. This study aimed to explore the role of LKB1/AMPK in the progression of OA.

Methods

Anterior cruciate ligament transection (ACLT) was performed on Sprague Dawley (SD) rats right knee to construct OA model, followed by AICAR [AMP-activated protein kinase (AMPK) activator] treatment. The level changes [AMPK, IL-10, IL-13, IL-1β, TNF-α, IL-6, ASC, Caspase-1, Ki67, and hibit Nod-like receptor protein 3 (NLRP3)] and the degree of tissue injury were assessed by western blot, Immunohistochemical (IHC), Enzyme-linked immunosorbent assay (ELISA), Hematoxylin-eosin staining (HE), Immunofluorescence (IF), Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, and Safranin O and Fast Green staining (S-O). Human chondrocytes were induced by LPS to construct a cellular inflammatory model, and then transfected with oe-AMPK or oe-HOIL-1-interacting protein (HOIP). Cell viability/apoptotic and intracellular content of AMPK, HOIP, IL-1β, IL-10, IL-13, TNF-α, IL-6, ASC, NLRP3 and Caspase-1 were measured by western blot, ELISA, CCK-8, IF, flow cytometry and TUNEL assays.

Results

After AICAR treatment with OA rats, the expression of p-AMPK, IL-10, IL-13, Ki67 and Bcl-2 increased, the level of NLRP3 inflammasome, TNF-α, IL-6, Bax and Caspase-3 levels were decreased, and tissue damage and apoptosis were significantly alleviated. After transfected with oe-LKB1, chondrocyte activity and LKB1 linear ubiquitination were enhanced, and the level of HOIP, p-AMPK, IL-10 and IL-13 were increased. In contrast, NLRP3 inflammasome (ASC, NLRP3, Caspase-1, IL-1β, and cleaved Caspase-1), TNF-α, and IL-6 levels decreased, apoptosis rate and TUNEL positive rate were attenuated.

Conclusion

LKB1/AMPK pathway significantly ameliorated NLRP3 inflammasome response and chondrocyte injury. Activation of AMPK pathway by linear ubiquitination of LKB1 may be a potential target for OA treatment.

The translational potential of this article

This study highlights the importance of the LKB1/AMPK pathway in NLRP3 inflammatory body response and chondrocyte injury. Activation of LKB1 by modulating linear ubiquitination may be a potential target for OA treatment.

ANGPTL4 Regulates Lung Adenocarcinoma Pyroptosis and Apoptosis via NLRP3\ASC\Caspase 8 Signaling Pathway to Promote Resistance to Gefitinib

BACKGROUND

Prior research has identified ANGPTL4 as a key player in the control of the body's lipid and glucose metabolism and a contributor to the onset of numerous cardiovascular conditions. Recently, it has been shown that ANGPTL4 also plays a critical role in tumor growth and progression. Nowadays, the number of EGFR-TKI resistant patients is increasing, and it is important to investigate the role of ANGPTL4 in regulating gefitinib resistance in PC9/GR non-small-cell lung cancer (NSCLC).

METHODS

The expression of ANGPTL4 in A549, PC9, H1975, BEAS-2B and PC9/GR cells was verified by Western blot and qRT-PCR assays, and the effect of gefitinib on the proliferative ability of each cell was probed by CCK-8 assay. By using shRNA to inhibit ANGPTL4 expression in cells, the effect of ANGPTL4 on cell migratory ability was examined and the effect of ANGPTL4 on cellular gefitinib sensitivity was confirmed using the CCK-8 assay and the edu proliferation test. Mouse transplantation tumors were constructed, and the effect of ANGPTL4 on cellular gefitinib sensitivity was investigated in vivo by flow cytometry, Tunel staining assay, immunohistochemical staining, and ROS fluorescence staining assay. ANGPTL4 expression in homoRNA overexpression cells was constructed, and the changes in the expression levels of ASC\NLRP3\Caspase 8 pathway and focal and apoptotic proteins were investigated in vitro, in vivo, afterknockdown and overexpression of ANGPTL4 expression by Westen blot assay.

RESULTS

ANGPTL4 was highly expressed in PC9/GR cells. Interfering with ANGPTL4 expression resulted in decreased proliferation and migration ability, decreased resistance to gefitinib, and increased scorching and apoptosis in PC9/GR cells. Interfering with ANGPTL4 expression in PC9/GR cells was shown to promote sensitivity to gefitinib and to mediate the NLRP3/ASC/Caspase 8 pathway to induce cell scorching and apoptosis.

CONCLUSIONS

ANGPTL4 promotes gefitinib resistance in PC9/GR cells by regulating the NLRP3/ASC/Caspase 8 pathway to inhibit scorch death. ANGPTL4 may be an effective new target for inhibiting EGFR-TKI resistance in lung adenocarcinoma cells.

Gastric alarmin release: A warning signal in the development of gastric mucosal diseases

Alarmins exist outside cells and are early warning signals to the immune system; as such, alarmin receptors are widely distributed on various immune cells. Alarmins, proinflammatory molecular patterns associated with tissue damage, are usually released into the extracellular space, where they induce immune responses and participate in the damage and repair processes of mucosal diseases.In the stomach, gastric alarmin release has been shown to be involved in gastric mucosal inflammation, antibacterial defense, adaptive immunity, and wound healing; moreover, this release causes damage and results in the development of gastric mucosal diseases, including various types of gastritis, ulcers, and gastric cancer. Therefore, it is necessary to understand the role of alarmins in gastric mucosal diseases. This review focuses on the contribution of alarmins, including IL33, HMGB1, defensins and cathelicidins, to the gastric mucosal barrier and their role in gastric mucosal diseases. Here, we offer a new perspective on the prevention and treatment of gastric mucosal diseases.

Identification of the Mechanism of Matrine Combined with Glycyrrhizin for Hepatocellular Carcinoma Treatment through Network Pharmacology and Bioinformatics Analysis

Matrine and glycyrrhizin are representative active ingredients of traditional Chinese medicine (TCM) used in clinical practice. Studies have demonstrated that matrine has antitumor pharmacological effects and that glycyrrhizin protects liver function. However, the potential bioactive compounds and mechanisms remain unknown, as well as whether they have synergistic effects in killing cancer cells and protecting liver cells. To investigate the synergistic effects and mechanism of matrine combined with glycyrrhizin in hepatocellular carcinoma (HCC) treatment, we used both network pharmacology and bioinformatics analyses. First, the chemical gene interaction information of matrine and glycyrrhizin was obtained from the PubChem database. The pathogenic genes of HCC were accessed from five public databases. The RNA sequencing data and clinical information of HCC patients were downloaded from The Cancer Genome Atlas (TCGA). Next, the overlapping genes among the potential targets of matrine and glycyrrhizin and HCC-related targets were determined using bioinformatics analysis. We constructed the drug-target interaction network. Prognosis-associated genes were acquired through the univariate Cox regression model and Lasso-Cox regression model. The results were verified by the International Cancer Genome Consortium (ICGC) database. Finally, we predicted the immune function of the samples. The drug-target interaction network consisted of 10 matrine and glycyrrhizin targets. We selected a Lasso-Cox regression model consisting of 3 differentially expressed genes (DEGs) to predict the efficacy of the combination in HCC. Subsequently, we successfully predicted the overall survival of HCC patients using the constructed prognostic model and investigated the correlation of the immune response. Matrine and glycyrrhizin have synergistic effects on HCC. The model we obtained consisted of three drug-target genes by Lasso-Cox regression analysis. The model independently predicted the combined effect of matrine and glycyrrhizin in HCC treatment and OS, which will be helpful for guiding clinical treatment. The prognostic model was correlated with the immune cells and immune checkpoints of patients, which had an adjuvant effect on HCC immunotherapy. Matrine and glycyrrhizin can have therapeutic effects on HCC by promoting the production or enhancing the core gene activity in the drug network and improving the immune system function of patients.

Activation of Inflammatory Networks in the Lungs Caused by Chronic Cold Stress Is Moderately Attenuated by Glucose Supplementation

Mammals that live in cold climates endure months of exposure to low temperature in the winter. The incidence of respiratory diseases has increased. The goal of this study was to investigate the effects of chronic cold stress on lung inflammatory networks, apoptosis, and mitochondrial function via Yorkshire pig models, as well as the ameliorative effect of glucose as energy supplements. Here, two trials were conducted (chronic cold stress and glucose supplementation). The results showed that chronic cold stress induced obvious inflammatory cell infiltration in the lungs and damaged the lung tissue structure. Compared with the Y-Con group, the expression of toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), high mobility group box 1 (HMGB1), nucleotide-binding domain, and leucine-rich repeat protein 3 (NLRP3), IL-1β, IL-2, IL-6, and IFN-γ in the lungs of the Y-CS group was enhanced by chronic cold stress (p < 0.05). Moreover, chronic cold stress promoted the expression of the Bax and Mfn2 in lungs of Y-CS group (p < 0.05). Interestingly, dietary glucose supplementation significantly reduced inflammatory cell infiltration in the lungs. Moreover, glucose supplementation inhibited the expression of TLR4, MyD88, HMGB1, NLRP3, IL-1β, IL-2, IL-6, IFN-γ, and Bax during chronic cold stress. In conclusion, chronic cold stress promoted inflammatory networks, apoptosis, and mitochondrial fusion in the lungs. Dietary glucose supplementation inhibited the inflammatory network during chronic cold stress.

Glycyrrhizic Acid Protects Experimental Sepsis Rats against Acute Lung Injury and Inflammation

Background

The incidence of acute lung injury/acute respiratory distress (ALI/ARDS) is high in sepsis aggravating morbidity and mortality. Glycyrrhizic acid (GA) has pharmacological activities in the treatment of inflammation and antiviral.

Materials and Methods

Sepsis rats were constructed by the cecal ligation and puncture (CLP) surgery. After GA (25 and 50 mg/kg) injection, the survival rate, blood oxygen, biochemical indexes, myeloperoxidase (MPO) activity, and wet/dry weight ratio of the lung were observed. The bronchoalveolar lavage fluid was collected to count the cells and measure the level of TNF-α, IL-1β, IL-10, and high mobility group box-1 protein (HMGB1). Lung tissue sections were taken to observe the levels of histopathological injury and apoptosis by HE and TUNEL staining. The levels of HMGB1, TLR4, p-38 MAPK, NF-κB, and ERK1/2 proteins were observed by immunohistochemistry and Western blot.

Results

GA treatment improved the survival rate, blood oxygen, ALT, AST, BUN, and Scr of CLP rats. It could advance the MPO activity, the wet/dry weight ratio, histopathological injury, apoptosis, and the IL-10 level in the lung. After GA injection, the number of total cells, neutrophils, and macrophages in the CLP rats was reduced and the levels of TNF-α, IL-1β, HMGB1, TLR4, p-38 MAPK, and ERK1/2 in the CLP rat were also repressed.

Conclusions

GA treatment may improve the sepsis-induced ALI/ARDS and inflammation by inhibiting HMBG1. This study provided an experimental basis for the prevention and treatment of ALI/ARDS caused by sepsis.

Spotlight on pyroptosis: role in pathogenesis and therapeutic potential of ocular diseases

Pyroptosis is a programmed cell death characterized by swift plasma membrane disruption and subsequent release of cellular contents and pro-inflammatory mediators (cytokines), including IL‐1β and IL‐18. It differs from other types of programmed cell death such as apoptosis, autophagy, necroptosis, ferroptosis, and NETosis in terms of its morphology and mechanism. As a recently discovered form of cell death, pyroptosis has been demonstrated to be involved in the progression of multiple diseases. Recent studies have also suggested that pyroptosis is linked to various ocular diseases. In this review, we systematically summarized and discussed recent scientific discoveries of the involvement of pyroptosis in common ocular diseases, including diabetic retinopathy, age-related macular degeneration, AIDS-related human cytomegalovirus retinitis, glaucoma, dry eye disease, keratitis, uveitis, and cataract. We also organized new and emerging evidence suggesting that pyroptosis signaling pathways may be potential therapeutic targets in ocular diseases, hoping to provide a summary of overall intervention strategies and relevant multi-dimensional evaluations for various ocular diseases, as well as offer valuable ideas for further research and development from the perspective of pyroptosis.

Signaling pathways involved in ischemic stroke: molecular mechanisms and therapeutic interventions

Ischemic stroke is caused primarily by an interruption in cerebral blood flow, which induces severe neural injuries, and is one of the leading causes of death and disability worldwide. Thus, it is of great necessity to further detailly elucidate the mechanisms of ischemic stroke and find out new therapies against the disease. In recent years, efforts have been made to understand the pathophysiology of ischemic stroke, including cellular excitotoxicity, oxidative stress, cell death processes, and neuroinflammation. In the meantime, a plethora of signaling pathways, either detrimental or neuroprotective, are also highly involved in the forementioned pathophysiology. These pathways are closely intertwined and form a complex signaling network. Also, these signaling pathways reveal therapeutic potential, as targeting these signaling pathways could possibly serve as therapeutic approaches against ischemic stroke. In this review, we describe the signaling pathways involved in ischemic stroke and categorize them based on the pathophysiological processes they participate in. Therapeutic approaches targeting these signaling pathways, which are associated with the pathophysiology mentioned above, are also discussed. Meanwhile, clinical trials regarding ischemic stroke, which potentially target the pathophysiology and the signaling pathways involved, are summarized in details. Conclusively, this review elucidated potential molecular mechanisms and related signaling pathways underlying ischemic stroke, and summarize the therapeutic approaches targeted various pathophysiology, with particular reference to clinical trials and future prospects for treating ischemic stroke.

Ginsenoside Rh2 Inhibits NLRP3 Inflammasome Activation and Improves Exosomes to Alleviate Hypoxia-Induced Myocardial Injury

The inflammatory microenvironment after acute myocardial infarction (MI) is a key limiting factor in the clinical application of stem cell transplantation and paracrine exosome therapy. Qishen Yiqi Pills contain a saponin ingredient called Ginsenoside Rh2 (Rh2) which exhibits a certain therapeutic effect on MI. However, the mechanism by which Rh2 alleviates the inflammatory microenvironment and improves the therapeutic efficiency of exosomes remains enigmatic. Here, we found that Rh2 attenuated the adverse effect of oxygen-glucose deprivation (OGD)-induced cellular injury, an in vitro pathological model of MI. Confocal microscopy revealed that DiI-labeled BMSCs-derived exosomes exhibited an increased homing ability of cardiomyocytes, which, in turn, inhibited the nuclear translocation of NF-κB p65 and NLRP3 inflammasome activation, thereby alleviating the inflammatory microenvironment and further facilitating the homing of exosomes to cardiomyocytes by forming a feed-forward enhancement loop. Additionally, we found that Rh2 could regulate the HMGB1/NF-κB signaling pathway to improve the OGD environment of cardiomyocytes, increasing the efficiency of the feed-forward loop. In conclusion, we found that Rh2 can improve the inflammatory microenvironment by enhancing the protection of exosomes against myocardial injury, providing new insights into the indirect modification of exosomes by Rh2 in MI treatment.

HMGB1-NLRP3-P2X7R pathway participates in PM2.5-induced hippocampal neuron impairment by regulating microglia activation

Neuroinflammation is a key mechanism underlying the cognitive impairment induced by PM_2.5, and activated microglia plays an important role in this process. However, the mechanisms by which activated microglia induced by PM_2.5 impair hippocampal neurons have not been fully elucidated. In this study, we focused on the role of HMGB1-NLRP3-P2X7R pathway which mediated the microglia activation in hippocampal neurons impairment induced by PM_2.5 using a co-culture model of microglia and hippocampal neurons. We found that PM_2.5 resulted in activated microglia and HMGB1-NLRP3 inflammatory pathway, and elevated proinflammatory cytokines of IL-18 and IL-1β in a dose-dependent manner. Notably, we next utilized previously reported pharmacological inhibitors or siRNA for HMGB1 and found that they significantly inhibited the activation of downstream NLRP3 and MAPK pathways derived from PM_2.5 exposure, and down-regulated IL-18 and IL-1β in microglia. Furthermore, we employed co-cultured hippocampal neurons and microglia and found that reducing HMGB1 significantly decreased neuron impairment, apoptosis related protein of cl-caspase3, synaptic damage, and neurotransmitter receptor of 5-HT2A, along with notably elevated presynaptic and postsynaptic proteins of SYP and PSD-95, as well as learning and memory related proteins of p-CREB and BDNF. The neuronal impairment induced by PM_2.5 could not be prevented in the case of simultaneous employment of HMGB1 siRNA and NLRP3 agonist. After silencing NLRP3 alone in microglia, hippocampal neurons demonstrated decreased excessive autophagy and up-regulated synaptic protein of GAP43 as well as learning and memory related protein of NCAM1. Therefore, we further studied how hippocampal neurons affected microglia under PM_2.5 exposure, Further investigation indicated that silencing HMGB1 could affect the activation of P2X7R and reduce the release of ATP from hippocampal neurons, thus protecting the interaction between microglia and hippocampal neurons. The present work suggests that regulation of HMGB1-NLRP3-P2X7R pathway can inhibit the microglia activation induced by PM_2.5 to alleviate hippocampal neuron impairment and stabilize the microenvironment between microglia and neurons. This contributes to maintaining the normal function of hippocampal neurons and alleviating the cognitive impairment derived from PM_2.5 exposure.

High-Mobility Group Box 1 Inhibitor BoxA Alleviates Neuroinflammation-Induced Retinal Ganglion Cell Damage in Traumatic Optic Neuropathy

Traumatic optic neuropathy (TON) is a significant cause of vision loss and irreversible blindness worldwide. It is defined as retinal ganglion cell death and axon degeneration caused by injury. Optic nerve crush (ONC), a well-validated model of TON, activates retinal microglia and initiates neuroinflammation. High-mobility group box 1 (HMGB1), a non-histone chromosomal binding protein in the nucleus of eukaryotic cells, is an important inducer of microglial activation and pro-inflammatory cytokine release. The purpose of this study was to examine the protective effects and mechanism of the HMGB1 inhibitor BoxA to neuroinflammation-induced retinal ganglion cells (RGCs) damage in traumatic optic neuropathy. For that purpose, an optic nerve crush model was established in C57BL/6J mice at 10–12 weeks. Model mice received an intravitreal injection of PBS and the HMGB1 inhibitor BoxA. Our data demonstrated that HMGB1 expression increased after optic nerve crush. Retinal ganglion cell function and morphology were damaged, and retinal ganglion cell numbers were reduced after optic nerve crush. Intravitreal injection of BoxA after ONC can alleviate damage. Furthermore, BoxA reduced microglial activation and expression levels of nuclear factor κB (NF-kB), nucleotide-binding domain, leucine-rich repeat containing protein 3 (NLRP3), and apoptosis-associated speck-like protein containing a CARD (ASC) in experimental ONC mice. In summary, HMGB1 mediates NLRP3 inflammasome via NF-kB to participate in retinal inflammatory injury after ONC. Thus, intravitreal injection of BoxA has potential therapeutic benefits for the effective treatment of RGC death to prevent TON.

HMGB1 signaling pathway in diabetes-related dementia: Blood-brain barrier breakdown, brain insulin resistance, and Aβ accumulation

Diabetes contributes to the onset of various diseases, including cancer and cardiovascular and neurodegenerative diseases. Recent studies have highlighted the similarities and relationship between diabetes and dementia as an important issue for treating diabetes-related cognitive deficits. Diabetes-related dementia exhibits several features, including blood-brain barrier disruption, brain insulin resistance, and Aβ over-accumulation. High-mobility group box1 (HMGB1) is a protein known to regulate gene transcription and cellular mechanisms by binding to DNA or chromatin via receptor for advanced glycation end-products (RAGE) and toll-like receptor 4 (TLR4). Recent studies have demonstrated that the interplay between HMGB1, RAGE, and TLR4 can impact both neuropathology and diabetic alterations. Herein, we review the recent research regarding the roles of HMGB1-RAGE-TLR4 axis in diabetes-related dementia from several perspectives and emphasize the importance of the influence of HMGB1 in diabetes-related dementia.

Inherited Retinal Dystrophies: Role of Oxidative Stress and Inflammation in Their Physiopathology and Therapeutic Implications

Inherited retinal dystrophies (IRDs) are a large group of genetically and clinically heterogeneous diseases characterized by the progressive degeneration of the retina, ultimately leading to loss of visual function. Oxidative stress and inflammation play fundamental roles in the physiopathology of these diseases. Photoreceptor cell death induces an inflammatory state in the retina. The activation of several molecular pathways triggers different cellular responses to injury, including the activation of microglia to eliminate debris and recruit inflammatory cells from circulation. Therapeutical options for IRDs are currently limited, although a small number of patients have been successfully treated by gene therapy. Many other therapeutic strategies are being pursued to mitigate the deleterious effects of IRDs associated with oxidative metabolism and/or inflammation, including inhibiting reactive oxygen species’ accumulation and inflammatory responses, and blocking autophagy. Several compounds are being tested in clinical trials, generating great expectations for their implementation. The present review discusses the main death mechanisms that occur in IRDs and the latest therapies that are under investigation.

No longer married to inflammasome signaling: the diverse interacting pathways leading to pyroptotic cell death

For over 15 years the lytic cell death termed pyroptosis was defined by its dependency on the inflammatory caspase, caspase-1, which, upon pathogen sensing, is activated by innate immune cytoplasmic protein complexes known as inflammasomes. However, this definition of pyroptosis changed when the pore-forming protein gasdermin D (GSDMD) was identified as the caspase-1 (and caspase-11) substrate required to mediate pyroptotic cell death. Consequently, pyroptosis has been redefined as a gasdermin-dependent cell death. Studies now show that, upon liberation of the N-terminal domain, five gasdermin family members, GSDMA, GSDMB, GSDMC, GSDMD and GSDME can all form plasma membrane pores to induce pyroptosis. Here, we review recent research into the diverse stimuli and cell death signaling pathways involved in the activation of gasdermins; death and toll-like receptor triggered caspase-8 activation of GSDMD or GSMDC, apoptotic caspase-3 activation of GSDME, perforin-granzyme A activation of GSDMB, and bacterial protease activation of GSDMA. We highlight findings that have begun to unravel the physiological situations and disease states that result from gasdermin signaling downstream of inflammasome activation, death receptor and mitochondrial apoptosis, and necroptosis. This new era in cell death research therefore holds significant promise in identifying how distinct, yet often networked, pyroptotic cell death pathways might be manipulated for therapeutic benefit to treat a range of malignant conditions associated with inflammation, infection and cancer.

Exploring the Mechanism of Ling-Gui-Zhu-Gan Decoction in Ventricular Remodeling after Acute Myocardial Infarction Based on UPLC and In Vivo Experiments

Ventricular remodeling (VR) after acute myocardial infarction (AMI) is an important pathophysiological basis for the development of chronic heart failure (CHF). At present, Ling-Gui-Zhu-Gan decoction (LGZGD) has been widely reported in the clinical treatment and basic research of cardiovascular diseases (CVDs), such as myocardial infarction, heart failure, and angina pectoris. However, the mechanism of LGZGD against VR after AMI remains unclear. Ultra-performance liquid chromatography (UPLC) was applied to investigate the major constituents of LGZGD, and molecular docking was used to predict the targets on the NLRP3/Caspase-1/GSDMD signaling pathway. In vivo, histological changes in the myocardium were visualized using HE staining and Masson staining, and cardiomyocyte apoptosis was detected using TUNEL. IL-1β activity in rat serum was determined by ELISA. Finally, NLRP3, Caspase-1, and GSDMD expressions were analyzed through RT-qPCR and Western blotting. The results showed that 8 authentic reference substances have been detected in LGZGD. Molecular docking showed that the major chemical constituents of LGZGD had a good binding activity with NLRP3, Caspase-1, and GSDMD. Our results showed that LGZGD treatment markedly improved cardiac pathology, decreased cardiomyocyte apoptosis, reduced IL-1β activity, and regulated the expression of genes and proteins related to the NLRP3/Caspase-1/GSDMD signal pathway. These results suggest that LGZGD protects against VR after AMI through NLRP3/Caspase-1/GSDMD signal pathway.

Targeting HMGB1-NFκb Axis and miR-21 by Glycyrrhizin: Role in Amelioration of Corneal Injury in a Mouse Model of Alkali Burn

Corneal neovascularization (CNV) is a sight-threatening condition usually associated with various inflammatory settings including chemical injury. High mobility group box 1 (HMGB1) is identified as an inflammatory alarmin in diverse tissue damage. Here, we evaluate the expression of HMGB1 and the consequences of its inhibition through its selective inhibitor glycyrrhizin (GLY) in alkali burn-induced corneal inflammation and neovascularization. GLY effectively attenuated alkali burn-induced HMGB1 expression at both mRNA and protein levels. Furthermore, slit-lamp analysis, ink perfusion, H&amp;E staining, and CD31 histochemical staining showed that GLY relieved corneal neovascularization, while GLY attenuated VEGF expression via inhibiting HMGB1/NF-κB/HIF-1α signal pathway. In addition, GLY treatment decreased the cytokine expression of CCL2 and CXCL5, accompanied by the reduction of their receptors of CCR2 and CXCR2. GLY diminished the inflammatory cell infiltration of the cornea, as well as reduced the expression of IL-1β, IL-6, and TNF-α. Moreover, treatment with GLY reduced the degree of cornea opacity through inactivating extracellular HMGB1 function, which otherwise induces TGF-β1 release and myofibroblast differentiation. Furthermore, we found that GLY treatment attenuated the upregulation of miR-21 levels in alkali burned cornea; while inhibition of miR-21in keratocytes in vitro, significantly inhibited TGF-β1-induced myofibroblast differentiation. Collectively, our results suggested that targeting HMGB1-NFκb axis and miR-21 by GLY could introduce a therapeutic approach to counter CNV.