CD5L induces inflammation and survival in RA-FLS through ERK1/2 MAPK pathway

OBJECTIVE

To explore the effect of CD5-like molecule (CD5L) on rheumatoid arthritis (RA) fibroblast-like synoviocytes (RA-FLS) and the relative molecular mechanism of CD5L in it.

METHODS

Recombinant protein CD5L was used to stimulate the cultured RA-FLS cells. The inflammation-related cytokines were determined by real time-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). The signal molecules and apoptosis-related molecules were detected by western blot assay (WB), and cell counting kit-8 (CCK-8) was used to detect the proliferation.

RESULTS

CD5L can increase the production of IL-6, IL-8, and TNF-α and this effect can be inhibited by signal pathway inhibitor. At the same time, CD5L activated ERK1/2 MAPK signal, inhibitor treatment can weaken the intensity of phosphorylation. In addition, CD5L can enhance the proliferation ability of RA-FLS.

CONCLUSION

CD5L induces the production of inflammatory cytokines in RA-FLS through the ERK1/2 MAPK pathway and increases cell survival.

Treatment with onion bulb extract both prevents and reverses allergic inflammation in a murine model of asthma

CONTEXT

Asthma presents a global health challenge. The main pharmacotherapy is synthetic chemicals and biological-based drugs that are costly, and have significant side effects. In contrast, use of natural products, such as onion (Allium cepa L., Amaryllidaceae) in the treatment of airway diseases has increased world-wide because of their perceived efficacy and little safety concerns. However, their pharmacological actions remain largely uncharacterized.

OBJECTIVE

We investigated whether onion bulb extract (OBE) can (1) reverse established asthma phenotype (therapeutic treatment) and/or (2) prevent the development of the asthma phenotype, if given before the immunization process (preventative treatment).

MATERIALS AND METHODS

Six groups of male Balb/c mice were established for the therapeutic (21 days) and five groups for the preventative (19 days) treatment protocols; including PBS and house dust mite (HDM)-challenged mice treated with vehicle or OBE (30, 60, and 100 mg/kg/i.p.). Airways inflammation was determined using cytology, histology, immunofluorescence, Western blot, and serum IgE.

RESULTS

Therapeutic (60 mg/kg/i.p.) and preventative (100 mg/kg/i.p.) OBE treatment resulted in down-regulation of HDM-induced airway cellular influx, histopathological changes and the increase in expression of pro-inflammatory signaling pathway EGFR, ERK1/2, AKT, pro-inflammatory cytokines and serum IgE.

DISCUSSION AND CONCLUSION

Our data show that OBE is an effective anti-inflammatory agent with both therapeutic and preventative anti-asthma effects. These findings imply that onion/OBE may be used as an adjunct therapeutic agent in established asthma and/or to prevent development of allergic asthma. However, further studies to identify the active constituents, and demonstrate proof-of-concept in humans are needed.

The role of NLRP3 inflammasome in type 2 inflammation related diseases

Type 2 inflammation related diseases, such as atopic dermatitis, asthma, and allergic rhinitis, are diverse and affect multiple systems in the human body. It is common for individuals to have multiple co-existing type 2 inflammation related diseases, which can impose a significant financial and living burden on patients. However, the exact pathogenesis of these diseases is still unclear. The NLRP3 inflammasome is a protein complex composed of the NLRP3 protein, ASC, and Caspase-1, and is activated through various mechanisms, including the NF-κB pathway, ion channels, and lysosomal damage. The NLRP3 inflammasome plays a role in the immune response to pathogens and cellular damage. Recent studies have indicated a strong correlation between the abnormal activation of NLRP3 inflammasome and the onset of type 2 inflammation. Additionally, it has been demonstrated that suppressing NLRP3 expression effectively diminishes the inflammatory response, highlighting its promising therapeutic applications. Therefore, this article reviews the role of NLRP3 inflammasome in the development and therapy of multiple type 2 inflammation related diseases.

Hydroxycitric acid and capsaicin combination alleviates obesity-induced testicular apoptosis, oxidative stress and inflammation

Recent research in rodents suggests that oxidative stress, inflammation, and apoptosis in the testes caused by high-fat diets (HFD) are a cause of male infertility. To investigate the therapeutic efficacy of the combination of hydroxycitric acid and capsaicin (HCC) against male reproductive disorders, we developed an HFD-induced obese rat model. Rats received HFD supplementation for 21 weeks, which induced obesity. From week 16, HCC (100 mg/kg body weight) was administered to investigate its potential to treat testicular toxicity. According to the results of the current study, treatment of obese rats with HCC improved their sperm quality, increased the production of testosterone, follicle-stimulating hormone, and luteinizing hormone and significantly increased the activities of steroidogenic enzymes and corresponding mRNA levels. In addition, HCC decreased lipid peroxidation and nitric oxide levels in both spermatozoa and testes while increasing the expression of mRNA for the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase in the testes, which in turn reduced oxidative stress in the testes. Moreover, after HCC treatment, testicular tissues showed a remarkable decrease in mRNA levels responsible for inflammation (TNF-α, IL-6, NF-κB) and apoptosis (Bax and Bcl-2). Our results suggest that HCC may alleviate obesity-induced male reproductive dysfunction by attenuating oxidative stress, inflammation, and apoptosis in the testes of HFD-induced obese male rats.

Prenatal exposure to intra-amniotic infection with Ureaplasma species increases the prevalence of bronchopulmonary dysplasia

OBJECTIVES

The present study investigated the relationship between bronchopulmonary dysplasia (BPD) and intra-amniotic infection with Ureaplasma species.

METHODS

This was a single-center, retrospective cohort study. Patients with singleton pregnancies who underwent inpatient management at our department for preterm premature rupture of membranes (PPROM), preterm labor, cervical insufficiency, and asymptomatic cervical shortening at 22-33 gestational weeks were included. Amniocentesis was indicated for patients with PPROM or an elevated maternal C-reactive protein level (≥0.58 mg/dL). Patients with an amniotic fluid IL-6 concentration ≥3.0 ng/mL were diagnosed with intra-amniotic inflammation, while those with positive aerobic, anaerobic, M. hominis, and Ureaplasma spp. cultures were diagnosed with microbial invasion of the amniotic cavity (MIAC). Patients who tested positive for both intra-amniotic inflammation and MIAC were considered to have intra-amniotic infection. An umbilical vein blood IL-6 concentration >11.0 pg/mL indicated fetal inflammatory response syndrome (FIRS). The maternal inflammatory response (MIR) and fetal inflammatory response (FIR) were staged using the Amsterdam Placental Workshop Group Consensus Statement.

RESULTS

Intra-amniotic infection with Ureaplasma spp. was diagnosed in 37 patients, intra-amniotic infection without Ureaplasma spp. in 28, intra-amniotic inflammation without MIAC in 58, and preterm birth without MIR/FIR and FIRS in 86 as controls. Following an adjustment for gestational age at birth, the risk of BPD was increased in patients with intra-amniotic infection with Ureaplasma spp. (adjusted odds ratio: 10.5; 95% confidence interval: 1.55-71.2), but not in those with intra-amniotic infection without Ureaplasma spp. or intra-amniotic inflammation without MIAC.

CONCLUSION

BPD was only associated with intra-amniotic infection with Ureaplasma species.

Knockdown of RTEL1 Alleviates Chronic Obstructive Pulmonary Disease by Modulating M1, M2 Macrophage Polarization and Inflammation

Chronic obstructive pulmonary disease (COPD) is a common chronic disease characterized by airflow obstruction, which seriously threatens people's health. The COPD mouse model was established with cigarette smoke induction. Hematoxylin-eosin staining and Masson staining were carried out to observe the pathological changes of lung tissues in COPD mice. RTEL1 was silenced in COPD mice, and immunohistochemistry was used to detect RTEL1, ki67 and Caspase-3 expression. The role of RTEL1 in inflammation were evaluated by ELISA, and the impacts of RTEL1 on M1 and M2 macrophage markers (iNOS and CD206) were evaluated by qPCR and western blotting. In COPD model, there was an increase in the number of inflammatory cells, with slightly disorganized cell arrangement, unclear hierarchy, condensed and solidified nuclei, while knockdown of RTEL1 improved the inflammatory infiltration. Moreover, knockdown of RTEL1 reduced ki67-positive cells and increased Caspase-3 positive cells in COPD group. The increased inflammatory factors (IL-1β, MMP-9, TNF-α, IL-4, IL-6, and IL-23) in COPD were suppressed by knockdown of RTEL1, while iNOS was raised and CD206 was inhibited. In conclusion, knockdown of RTEL1 promoted M1 and inhibited M2 macrophage polarization and inflammation to alleviate COPD.

Extracellular Caspase-1 induces hair stem cell migration in wounded and inflamed skin conditions

The wound-healing process is a paradigm of the directed migration of various pools of stem cells from their niche to the site of injury where they replenish damaged cells. Two decades have elapsed since the observation that wounding activates multipotent hair follicle stem cells to infiltrate the epidermis, but the cues that coax these cells out of their niche remain unknown. Here, we report that Caspase-1, a protein classically known as an integral component of the cytosolic inflammasome, is secreted upon wounding and has a non-canonical role in the extracellular milieu. Through its caspase activation recruitment domain (CARD), Caspase-1 is sufficient to initiate the migration of hair follicle stem cells into the epidermis. Uncovering this novel function of Caspase-1 also facilitates a deeper understanding of the mechanistic basis of the epithelial hyperplasia found to accompany numerous inflammatory skin diseases.

Anti-inflammatory effects and related mechanisms in vitro and in vivo of Hedychium coccineum rhizome essential oil

ETHNOPHARMACOLOGICAL RELEVANCE

Hedychium coccineum rhizome is an anti-inflammatory ethnomedicine used to remedy inflammation-related swelling and bronchial asthma.

AIM OF THE STUDY

The study aimed to analyze the phytochemical constituents of H. coccineum rhizome essential oil (EO) and evaluate its in vitro and in vivo anti-inflammatory effects and underlying mechanisms.

MATERIALS AND METHODS

Phytochemical constituents of H. coccineum rhizome EO were analyzed using GC-FID/MS. In RAW264.7 macrophages induced by LPS, blockade of PGE2, NO, IL-1β, IL-6, and TNF-α secretion by H. coccineum rhizome EO was measured, and then Western blot, qRT-PCR, and immunofluorescent staining were used to evaluate its underlying mechanisms. Moreover, we used the xylene-induced ear edema model for testing anti-inflammatory potential in vivo and examined auricular swelling as well as tissue and serum contents of IL-1β, IL-6, and TNF-α.

RESULTS

EO's main components were E-nerolidol (40.5%), borneol acetate (24.8%), spathulenol (4.5%), linalool (3.8%), elemol (3.5%), and borneol (3.4%). In RAW264.7 cells stimulated by LPS, EO downregulated the expression of pro-inflammatory enzyme (iNOS and COX-2) genes and proteins, thereby suppressing pro-inflammatory mediators (NO and PGE2) secretion. Simultaneously, it reduced TNF-α, IL-1β, and IL-6 release by downregulating their mRNA expression. Besides, H. coccineum EO attenuated LPS-stimulated activation of NF-κB (by reducing IκBα phosphorylation and degradation to inhibit NF-κB nuclear translocation) and MAPK (by downregulating JNK, p38, and ERK phosphorylation). In xylene-induced mouse ear edema, EO relieved auricular swelling and lowered serum and tissue levels of TNF-α, IL-1β, and IL-6.

CONCLUSIONS

H. coccineum EO had powerful in vivo and in vitro anti-inflammatory effects by inhibiting MAPK and NF-κB activation. Hence, H. coccineum EO should have great potential for application in the pharmaceutical field as a novel anti-inflammatory agent.

Effect and mechanism of Prunella vulgaris L. extract on alleviating lipopolysaccharide-induced acute mastitis in protecting the blood-milk barrier and reducing inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

According to ancient literature, Prunella vulgaris L. (P vulgaris) alleviates mastitis and has been used in China for many years; however, there are no relevant reports that confirm this or the mechanism of its efficacy.

AIM OF THE STUDY

To explore the anti-acute mastitis effect and potential mechanism of P vulgaris extract.

MATERIALS AND METHODS

First, the active ingredients and targets of P vulgaris against mastitis were predicted using network pharmacology. Next, the relevant active ingredients were enriched using macroporous resins and verified using UV and UPLC-Q-TOF-MS/MS. Lastly, a mouse model of acute mastitis was established by injecting lipopolysaccharides into the mammary gland and administering P vulgaris extract by oral gavage. The pathological changes in mammary tissue were observed by HE staining. Serum and tissue inflammatory factors were measured by ELISA method. MPO activity in mammary tissue was measured using colorimetry and MPO expression was detected by immunohistochemistry. The expression of tight junction proteins (ZO-1, claudin-3, and occludin) in mammary tissue was detected by immunofluorescence and Western blot. iNOS and COX-2 in mammary tissue were detected by Western blot. MAPK pathway and NF-κB pathway related proteins were also detected by Western blot.

RESULTS

Network pharmacology predicted that phenolic acids and flavonoids in P vulgaris had anti-mastitis effects. The contents of total flavonoids and total phenolic acids in P vulgaris extract were 64.5% and 29.4%, respectively. UPLC-Q-TOF-MS/MS confirmed that P vulgaris extract contained phenolic acids and flavonoids. The results of animal experiments showed that P vulgaris extract reduced lipopolysaccharide-induced inflammatory edema, inflammatory cell infiltration, and interstitial congestion of mammary tissue. It also reduced the levels of serum and tissue inflammatory factors TNF-α, IL-6, and IL-1β, and inhibited the activation of MPO. Furthermore, it downregulated the expression of MAPK and NF-κB pathway-related proteins. The expressions of ZO-1, occludin, and claudin-3 in mammary gland tissues were upregulated.

CONCLUSIONS

P vulgaris extract can maintain the integrity of mammary connective tissue and reduce its inflammatory response to prevent acute mastitis. Its mechanism probably involves regulating NF-κB and MAPK pathways.

Type I interferon regulates interleukin-1beta and IL-18 production and secretion in human macrophages

Inflammasomes are immune complexes whose activation leads to the release of pro-inflammatory cytokines IL-18 and IL-1β. Type I IFNs play a role in fighting infection and stimulate the expression of IFN-stimulated genes (ISGs) involved in inflammation. Despite the importance of these cytokines in inflammation, the regulation of inflammasomes by type I IFNs remains poorly understood. Here, we analysed RNA-sequencing data from patients with monogenic interferonopathies and found an up-regulation of several inflammasome-related genes. To investigate the effect of type I IFN on the inflammasome, we treated human monocyte-derived macrophages with IFN-α and observed an increase in CASP1 and GSDMD mRNA levels over time, whereas IL1B and NLRP3 were not directly correlated to IFN-α exposure time. IFN-α treatment reduced the release of mature IL-1β and IL-18, but not caspase-1, in response to ATP-mediated NLRP3 inflammasome activation, suggesting regulation occurs at cytokine expression levels and not the inflammasome itself. However, more studies are required to investigate how regulation by IFN-α occurs and impacts NLRP3 and other inflammasomes at both transcriptional and post-translational levels.

L- lactate inhibits lipopolysaccharide-induced inflammation of microglia in the hippocampus

Objective: Depression is a common psychological and physiological disease in the world, which seriously affects the quality of life of patients and families. Exercise is an economic and noninvasive antidepressant measure, which has been widely recognized and applied in daily life and clinical practice, and the related mechanism research has also been paid attention to. In recent years, a new research report pointed out that peripheral administration of L-lactate can reverse depression-like behavior in mice, which suggesting that the lactic acid produced during exercise may be one of the factors leading to antidepressant effect, but the detailed mechanism is not clear. Inflammation is the pathogenic factor of many diseases and a large number of experiments have proved that inflammation is also an important pathogenic factor leading to depression. The purpose of our experiment is to explore whether lactic acid has anti-inflammatory and antidepressant effects.Methods: Based on the LPS induced inflammatory model, animal behavior observation, protein extraction, Western blotting, immunofluorescence and other techniques were used in this experiment.Results: Lactic acid could inhibit the change of some important inflammatory factors, such as TNF-αIL-1βphospho-NF-κB (p-NF-κB) and NLRP3 inflammasome complex (NLRP3/ASC/caspase-1) induced by LPS.Conclusion: Our current research suggested that lactic acid maybe exert antiinflammatory effect by inhibiting inflammatory factors.

Gut bacterial markers involved in association of dietary inflammatory index with visceral adiposity

OBJECTIVE

To deepen the understanding of the influence of diet on weight gain and metabolic disturbances, we examined associations between diet-related inflammation and body composition and fecal bacteria abundances in participants of the Nutritionists' Health Study.

METHODS

Early-life, dietary and clinical data were obtained from 114 women aged ≤45 years. A validated food frequency questionnaire was used to calculate the energy-adjusted dietary inflammatory index (E-DII). Participants' data were compared by E-DII quartiles using ANOVA or Kruskal-Wallis. Associations of DXA-determined body composition with the E-DII were tested by multiple linear regression using DAG-oriented adjustments. Fecal microbiota was analyzed targeting the V4 region of the 16S rRNA gene. Spearman correlation coefficients were used to test linear associations; differential abundance of genera across the E-DII quartiles was assessed by pair-wise comparisons.

RESULTS

E-DII score was associated with total fat (b=1.80, p<0.001), FMI (b=0.08, p<0.001) and visceral fat (b=1.19, p=0.02), independently of maternal BMI, birth type and breastfeeding. E-DII score was directly correlated to HOMA-IR (r=0.30; p=0.004), C-reactive protein (r=0.29; p=0.003) and to the abundance of Actinomyces, and inversely correlated to the abundance of Eubacterium.xylanophilum.group. Actinomyces were significantly more abundant in the highest (most proinflammatory) E-DII quartile.

CONCLUSIONS

Association of E-DII with markers of insulin resistance, inflammation, body adiposity and certain gut bacteria are consistent with beneficial effects of anti-inflammatory diet on body composition and metabolic profile. Bacterial markers, such as Actinomyces, could be involved in the association between the dietary inflammation with visceral adiposity. Studies designed to explore how a pro-inflammatory diet affects both central fat deposition and gut microbiota are needed.

Exploration of gut microbiome and inflammation: A review on key signalling pathways

The gut microbiome, a crucial component of the human system, is a diverse collection of microbes that belong to the gut of human beings as well as other animals. These microbial communities continue to coexist harmoniously with their host organisms and perform various functions that affect the host's general health. Each person's gut microbiota has a unique makeup. The gut microbiota is well acknowledged to have a part in the local as well as systemic inflammation that underlies a number of inflammatory disorders (e.g., atherosclerosis, diabetes mellitus, obesity, and inflammatory bowel disease).The gut microbiota's metabolic products, such as short-chain fatty acids (butyrate, propionate, and acetate) inhibit inflammation by preventing immune system cells like macrophages and neutrophils from producing pro-inflammatory factors, which are triggered by the structural elements of bacteria (like lipopolysaccharide). The review's primary goal is to provide comprehensive and compiled data regarding the contribution of gut microbiota to inflammation and the associated signalling pathways.

Molecular and pathophysiological relationship between obesity and chronic inflammation in the manifestation of metabolic dysfunctions and their inflammation‑mediating treatment options (Review)

Obesity reaches up to epidemic proportions globally and increases the risk for a wide spectrum of co‑morbidities, including type‑2 diabetes mellitus (T2DM), hypertension, dyslipidemia, cardiovascular diseases, non‑alcoholic fatty liver disease, kidney diseases, respiratory disorders, sleep apnea, musculoskeletal disorders and osteoarthritis, subfertility, psychosocial problems and certain types of cancers. The underlying inflammatory mechanisms interconnecting obesity with metabolic dysfunction are not completely understood. Increased adiposity promotes pro‑inflammatory polarization of macrophages toward the M1 phenotype, in adipose tissue (AT), with subsequent increased production of pro‑inflammatory cytokines and adipokines, inducing therefore an overall, systemic, low‑grade inflammation, which contributes to metabolic syndrome (MetS), insulin resistance (IR) and T2DM. Targeting inflammatory mediators could be alternative therapies to treat obesity, but their safety and efficacy remains to be studied further and confirmed in future clinical trials. The present review highlights the molecular and pathophysiological mechanisms by which the chronic low‑grade inflammation in AT and the production of reactive oxygen species lead to MetS, IR and T2DM. In addition, focus is given on the role of anti‑inflammatory agents, in the resolution of chronic inflammation, through the blockade of chemotactic factors, such as monocytes chemotractant protein‑1, and/or the blockade of pro‑inflammatory mediators, such as IL‑1β, TNF‑α, visfatin, and plasminogen activator inhibitor‑1, and/or the increased synthesis of adipokines, such as adiponectin and apelin, in obesity‑associated metabolic dysfunction.

Pepsin-mediated inflammation in laryngopharyngeal reflux via the ROS/NLRP3/IL-1β signaling pathway

BACKGROUND

Laryngopharyngeal reflux (LPR) is one of the most common disorders in otorhinolaryngology, affecting up to 10% of outpatients visiting otolaryngology departments. In addition, 50% of hoarseness cases are related to LPR. Pepsin reflux-induced aseptic inflammation is a major trigger of LPR; however, the underlying mechanisms are unclear. The nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome has become an important bridge between stimulation and sterile inflammation and is activated by intracellular reactive oxygen species (ROS) in response to danger signals, leading to an inflammatory cascade. In this study, we aimed to determine whether pepsin causes LPR-associated inflammatory injury via mediating inflammasome activation and explore the potential mechanism.

METHODS

We evaluated NLRP3 inflammasome expression and ROS in the laryngeal mucosa using immunofluorescence and immunohistochemistry. Laryngeal epithelial cells were exposed to pepsin and analyzed using flow cytometry, western blotting, and real-time quantitative PCR to determine ROS, NLRP3, and pro-inflammatorycytokine levels.

RESULTS

Pepsin expression was positively correlated with ROS as well as caspase-1 and IL-1β levels in laryngeal tissues. Intracellular ROS levels were elevated by increased pepsin concentrations, which were attenuated by apocynin (APO)-a ROS inhibitor-in vitro. Furthermore, pepsin significantly induced the mRNA and protein expression of thioredoxin-interacting protein, NLRP3, caspase-1, and IL-1β in a dose-dependent manner. APO and the NLRP3 inhibitor, MCC950, inhibited NLRP3 inflammasome formation and suppressed laryngeal epithelial cell damage.

CONCLUSION

Our findings verified that pepsin could regulate the NLRP3/IL-1β signaling pathway through ROS activation and further induce inflammatory injury in LPR. Targeting the ROS/NLRP3 inflammasome signaling pathway may help treat patients with LPR disease.

Mesenteric adipose tissue B lymphocytes promote intestinal injury in severe acute pancreatitis by mediating enteric pyroptosis

BACKGROUND

Visceral adipose tissue (VAT) has been linked to the severe acute pancreatitis (SAP) prognosis, although the underlying mechanism remains unclear. It has been reported that pyroptosis worsens SAP. The present study aimed to verify whether mesenteric adipose tissue (MAT, a component of VAT) can cause secondary intestinal injury through the pyroptotic pathway.

METHODS

Thirty-six male Sprague Dawley (SD) rats were divided into six different groups. Twelve rats were randomly divided into the SAP and control groups. We monitored the changes of MAT and B lymphocytes infiltration in MAT of SAP rats. Twelve SAP rats were injected with MAT B lymphocytes or phosphate buffer solution (PBS). The remaining twelve SAP rats were first injected with MAT B lymphocytes, and then with MCC950 (NLRP3 inhibitor) or PBS. We collected blood and tissue samples from pancreas, gut and MAT for analysis.

RESULTS

Compared to the control rats, the SAP group showed inflammation in MAT, including higher expression of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6), lower expression of IL-10, and histological changes. Flow cytometry analysis revealed B lymphocytes infiltration in MAT but not T lymphocytes and macrophages. The SAP rats also exhibited intestinal injury, characterized by lower expression of zonula occludens-1 (ZO-1) and occludin, higher levels of lipopolysaccharide and diamine oxidase, and pathological changes. The expression of NLRP3 and n-GSDMD, which are responsible for pyroptosis, was increased in the intestine of SAP rats. The injection of MAT B lymphocytes into SAP rats exacerbated the inflammation in MAT. The upregulation of pyroptosis reduced tight junction in the intestine, which contributed to the SAP progression, including higher inflammatory indicators and worse histological changes. The administration of MCC950 to SAP + MAT B rats downregulated pyroptosis, which subsequently improved the intestinal barrier and ameliorated inflammatory response of SAP.

CONCLUSIONS

In SAP, MAT B lymphocytes aggravated local inflammation, and promoted the injury to the intestine through the enteric pyroptotic pathway.

Octreotide attenuates intestinal barrier damage by maintaining basal autophagy in Caco2 cells

The intestinal mucosal barrier is of great importance for maintaining the stability of the internal environment, which is closely related to the occurrence and development of intestinal inflammation. Octreotide (OCT) has potential applicable clinical value for treating intestinal injury according to previous studies, but the underlying molecular mechanisms have remained elusive. This article is based on a cell model of inflammation induced by lipopolysaccharide (LPS), aiming to explore the effects of OCT in protecting intestinal mucosal barrier function. A Cell Counting Kit‑8 assay was used to determine cell viability and evaluate the effectiveness of OCT. Gene silencing technology was used to reveal the mediated effect of somatostatin receptor 2 (SSTR2). The changes in intestinal permeability were detected through trans‑epithelial electrical resistance and fluorescein isothiocyanate‑dextran 4 experiments, and the alterations in tight junction proteins were detected using immunoblotting and reverse transcription fluorescence‑quantitative PCR technology. Autophagosomes were observed by electron microscopy and the dynamic changes of the autophagy process were characterized by light chain (LC)3‑II/LC3‑I conversion and autophagic flow. The results indicated that SSTR2‑dependent OCT can prevent the decrease in cell activity. After LPS treatment, the permeability of monolayer cells decreased and intercellular tight junctions were disrupted, resulting in a decrease in tight junction protein zona occludens 1 in cells. The level of autophagy‑related protein LC3 was altered to varying degrees at different times. These abnormal changes gradually returned to normal levels after the combined application of LPS and SSTR2‑dependent OCT, confirming the role of OCT in protecting intestinal barrier function. These experimental results suggest that OCT maintains basal autophagy and cell activity mediated by SSTR2 in intestinal epithelial cells, thereby preventing the intestinal barrier dysfunction in inflammation injury.

ACKR3 in olfactory glia cells shapes the immune defense of the olfactory mucosa

Barrier-forming olfactory glia cells, termed sustentacular cells, play important roles for immune defense of the olfactory mucosa, for example as entry sites for SARS-CoV-2 and subsequent development of inflammation-induced smell loss. Here we demonstrate that sustentacular cells express ACKR3, a chemokine receptor that functions both as a scavenger of the chemokine CXCL12 and as an activator of alternative signaling pathways. Differential gene expression analysis of bulk RNA sequencing data obtained from WT and ACKR3 conditional knockout mice revealed upregulation of genes involved in immune defense. To map the regulated genes to the different cell types of the olfactory mucosa, we employed biocomputational methods utilizing a single-cell reference atlas. Transcriptome analysis, PCR and immunofluorescence identified up-regulation of NF-κB-related genes, known to amplify inflammatory signaling and to facilitate leukocyte transmigration, in the gliogenic lineage. Accordingly, we found a marked increase in leukocyte-expressed genes and confirmed leukocyte infiltration into the olfactory mucosa. In addition, lack of ACKR3 led to enhanced expression and secretion of early mediators of immune defense by Bowman's glands. As a result, the number of apoptotic cells in the epithelium was decreased. In conclusion, our research underlines the importance of sustentacular cells in immune defense of the olfactory mucosa. Moreover, it identifies ACKR3, a druggable G protein-coupled receptor, as a promising target for modulation of inflammation-associated anosmia.

Deciphering microglial activation and neuronal apoptosis post‑traumatic brain injury: The role of TYROBP in inflammation regulation networks

Traumatic Brain Injury (TBI) represents a significant public health challenge. Recovery from brain injury necessitates the collaborative efforts of various resident neural cells, predominantly microglia. The present study analyzed rat and mouse RNA expression micro‑arrays, high‑throughput RNA sequencing and single‑cell sequencing data sourced from public databases. To construct an inflammation regulation network around TYRO protein tyrosine kinase‑binding protein (TYROBP), to evaluate the role of TYROBP in cell death after TBI. These findings indicate that following TBI, neurons predominantly communicate with one another through the CXC chemokine ligand (CXCL) and CC chemokine ligand (CCL) signaling pathways, employing a paracrine mechanism to activate microglia. These activated microglia intensify the pathological progression of brain injury by releasing factors such as tumor necrosis factor α (TNF‑α), vascular endothelial growth factor and transforming growth factor β via the NF‑κB pathway. Cells co‑culture experiments demonstrated that neurons, impaired by mechanical injury, interact with microglia through non‑contact mechanisms. Activated microglia secrete cytokines, including TNF‑α, CXCL‑8 and CCL2, which trigger an inflammatory response and facilitate neuronal apoptosis. TYROBP gene knockout in microglia was demonstrated to reduce this interaction and reduce neuronal cell apoptosis rates.

Mincle as a potential intervention target for the prevention of inflammation and fibrosis (Review)

Macrophage‑inducible C‑type lectin receptor (Mincle) is predominantly found on antigen‑presenting cells. It can recognize specific ligands when stimulated by certain pathogens such as fungi and Mycobacterium tuberculosis. This recognition triggers the activation of the nuclear factor‑κB pathway, leading to the production of inflammatory factors and contributing to the innate immune response of the host. Moreover, Mincle identifies lipid damage‑related molecules discharged by injured cells, such as Sin3‑associated protein 130, which triggers aseptic inflammation and ultimately hastens the advancement of renal damage, autoimmune disorders and malignancies by fostering tissue inflammation. Presently, research on the functioning of the Mincle receptor in different inflammatory and fibrosis‑associated conditions has emerged as a popular topic. Nevertheless, there remains a lack of research on the impact of Mincle in promoting long‑lasting inflammatory reactions and fibrosis. Additional investigation is required into the function of Mincle receptors in chronological inflammatory reactions and fibrosis of organ systems, including the progression from inflammation to fibrosis. Hence, the present study showed an overview of the primary roles and potential mechanism of Mincle in inflammation, fibrosis, as well as the progression of inflammation to fibrosis. The aim of the present study was to clarify the potential mechanism of Mincle in inflammation and fibrosis and to offer perspectives for the development of drugs that target Mincle.

MZB1 regulates cellular proliferation, mitochondrial dysfunction, and inflammation and targets the PI3K-Akt signaling pathway in acute pancreatitis

BACKGROUND

Acute pancreatitis (AP) is a pathological condition characterized by the premature release and activation of trypsinogens and other enzyme precursors. In severe cases, the mortality rates are in the range of 20-30% and may even be as high as 50%. Though various prophylaxes are available for AP, the mechanism of its progression is unclear. Marginal zone B and B-1 cell-specific protein 1 (MZB1) is found in the endoplasmic reticulum (ER) where it is expressed exclusively in the B cells there. MZB1 promotes proliferation, inhibits apoptosis, invasion, and inflammation, and mitigates mitochondrial damage in cells. However, the importance of MZB1 in AP has not yet been determined.

METHODS

Differentially expressed genes (DEGs) between healthy pancreatic cells and those affected by AP were identified using datasets from Gene Expression Omnibus (GEO) datasets. Relative differences in MZB1 expression between normal and diseased tissues and cells were validated in vivo using a rat AP model induced with 4% (w/v) sodium taurocholate and in vitro using the AR42J rat pancreatic cell line exposed to caerulein (CAE). Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2`-deoxyuridine (EdU) assays were performed to detect and compare normal and pathological cell proliferation. Flow cytometry was employed to assess and compare cellular apoptosis. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot (WB) were applied to evaluate the apoptotic factors Bax and Bcl. The inflammatory factors interleukin (IL)-6 and IL-1β were quantified using Enzyme-linked immunosorbent assay (ELISA) and qRT-PCR techniques. Mitochondrial function was evaluated using assays for reactive oxygen species (ROS) and tetramethylrhodamine methyl ester (TMRM). WB and qRT-PCR were utilized to measure the expression levels of the PI3K-Akt signaling pathway, followed by a rescue experiment involving the inhibitor of wortmannin.

RESULTS

MZB1 was upregulated in the AP cases screened from the GEO datasets, the rat AP model, and the AR42J cells exposed to CAE. Overexpression of MZB1 enhanced the growth and supressed the cell death of AR42J cells while also activating the PI3K-Akt signaling pathway. MZB1 knockdown led to mitochondrial dysfunction and exacerbated inflammation. The rescue experiment demonstrated that MZB1 enhanced proliferation and inhibited apoptosis, mitochondrial dysfunction, and inflammation in pancreatic cells through the PI3K-Akt pathway.

CONCLUSIONS

AP cells and tissues exhibited markedly elevated levels of MZB1 expression compared to their healthy counterparts. MZB1 overexpression promoted proliferation and supressed apoptosis, mitochondrial dysfunction, and inflammation in pancreatic cells through the positive regulation of the PI3K-Akt signaling pathway.

Protopine protects chondrocytes from undergoing ferroptosis by activating Nrf2 pathway

Osteoarthritis is a highly prevalent joint disease; however, effective treatments are lacking. Protopine (PTP) is an isoquinoline alkaloid with potent anti-inflammatory and antioxidant properties; however, it has not been studied in osteoarthritis. This study aimed to investigate whether PTP can effectively protect chondrocytes from ferroptosis. Primary mouse chondrocytes were treated with tert-butyl hydroperoxide (TBHP) to simulate oxidative stress in an in vitro model of osteoarthritis. Two concentrations of PTP (10 and 20 μg/mL) were validated for in vitro experiments. Cellular inflammation and metabolism were detected using RT-qPCR and western blotting (WB). Ferroptosis was assessed via WB, qPCR, reactive oxygen species (ROS) levels, lipid ROS, and immunofluorescence staining. In vitro, PTP significantly ameliorated chondrocyte inflammation and cytolytic metabolism and significantly suppressed chondrocyte ferroptosis through the activation of the Nrf2 pathway. The anterior cruciate ligament transection (ACLT) mouse model was used to validate the in vivo effects of PTP. The joint cartilage was assessed using the Osteoarthritis Research Society International (OARSI) score, Safranin O staining, and immunohistochemistry. The intra-articular administration of PTP alleviated cartilage inflammation and ferroptosis, as evidenced by the expression of MMP3, MMP13, COL2A1, GPX4, and Nrf2. Overall, we find that PTP exerted anti-ferroptosis and anti-inflammatory effects on chondrocytes to protect the articular cartilage.

Shengjihuayu formula ameliorates the oxidative injury in human keratinocytes via blocking JNK/c-Jun/MMPs signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The reactive oxygen species (ROS) surge in the chronic wound tissue of diabetic ulcers (DUs) aggravates the inflammatory response. The oxidative stress state during inflammation will exacerbate inflammation and cause tissue damage, resulting in prolonged wound healing. Shengjihuayu Formula (SJHYF) is a renowned Chinese medicine prescription for treating chronic wounds in diabetic ulcers. Growing clinical evidence has demonstrated that SJHYF exhibits superior therapeutic efficacy and has a favorable safety profile. However, the underlying mechanisms by which SJHYF ameliorates oxidative damage under pathological conditions of DUs remain unclear.

OBJECTIVE

To investigate the cytoprotective properties of SJHYF on hydrogen peroxide (H2O2)-induced cell damage in human HaCaT keratinocytes and to explore its potential targets and molecular pathways in treating DUs using RNA-seq.

METHODS

HaCaT cells were incubated with H2O2 for 24 h to construct an oxidative stress cell model. Cell viability and proliferation were measured using the MTT and EdU assays, respectively. Cell migration was assessed using the scratch assay, and the fluorescence intensity of ROS was measured using the DCFH-DA probe. The chemical components of SJHYF were analyzed by UPLC-Q-TOF/MS, while the therapeutic effects of SJHYF on H2O2-induced HaCaT cells were analyzed using RNA-Seq. The potential target genes were validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). At the same time, the pathway phenotype expression of SJHYF on the protection of H2O2-induced HaCaT cells was explored using Western Blot.

RESULTS

The application of SJHY at a concentration of 0.25 mg/mL promoted cell proliferation, cell migration, and reduced ROS production. In addition, SJHYF was detected to have a total of 93 active compounds, including key components such as Galloyl-beta-D-glucose, Danshensu, Procyanidin B2, Catechin, and Alkannin. The RNA-seq analysis identified several core targets namely KRT17, TGM1, JUNB, PRDX5, TXNIP, PRDX1, HSP90AA1, HSP90AB1, HSPA8, and TNF-α. Western blot revealed the presence of the JNK/c-Jun/MMPs pathway and its related transcription factors.

CONCLUSION

SJHYF displays significant protective effects on H2O2-induced oxidative cell damage in HaCaT cells via blocking the JNK/c-Jun/MMPs pathway.

Inhibition of p38 MAPK/NF-κB p65 signaling pathway activity by rare ginsenosides ameliorates cyclophosphamide-induced premature ovarian failure and KGN cell injury

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C. A. Mey., one of the most used herbs in the world, shows effective treatment in reproductive injury. Recent studies have proven that the processed product, red ginseng, which is more active than ginseng itself. Therefore, it is speculated that its main functional component, rare ginsenosides (heat-transformed saponin, HTS), may be effective in treating premature ovarian failure (POF), but its efficacy has not yet been experimentally confirmed.

AIM OF THE STUDY

To evaluate whether HTS could attenuate cyclophosphamide-induced inflammation and oxidative damage in POF model rats and the human granulosa-like KGN cell line and protect granulosa cell proliferation.

MATERIAL AND METHODS

HTS were isolated from ginsenosides and high performance liquid chromatography (HPLC) analysis was used to analyze the HTS components. Cyclophosphamide (CP) was used to establish a POF rat model and KGN cell injury model. Reactive oxygen species (ROS) and antioxidant enzyme production was determined using specific assays, while inflammatory cytokine secretion was measured by enzyme-linked immunosorbent assay (ELISA). The proliferative function of granulosa cells was assessed using high-content screening and immunohistochemistry to determine the Ki67 protein level. Protein expression in ovarian tissues and KGN cells was analyzed by Western blotting, quantitative real-time PCR (qRT-PCR) was used to determine the transcriptional changes in ovarian tissues and KGN cells.

RESULTS

In CP-treated POF model rats, HTS significantly decreased malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) levels, increased glutathione oxidase (GSH) levels, and upregulated Ki67 expression in ovarian granulosa cells. In addition, HTS significantly increased cell survival and Ki67 expression levels in CP-treated cells, and superoxide dismutase (SOD) levels were significantly increased. HTS significantly downregulated IL-6, TNF-α, and interleukin-1β (IL-1β) mRNA expression and significantly inhibited nuclear factor kappa-B p65 (NF-κB p65) and p38 mitogen activated protein kinase (p38 MAPK) phosphorylation in POF model rats and KGN cells. Moreover, NF-κB p65 and p38 MAPK levels were significantly increased in ovarian granulosa cells. p65 and p38 protein and gene expression was significantly downregulated.

CONCLUSION

HTS ameliorated CP-induced POF and human granulosa cell injury, possibly by inhibiting inflammation and oxidative damage mediated by the p38 MAPK/NF-κB p65 signaling pathway.

The mast cells - Cytokines axis in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a neurodevelopmental disturbance, diagnosed in early childhood. It is associated with varying degrees of dysfunctional communication and social skills, repetitive and stereotypic behaviors. Regardless of the constant increase in the number of diagnosed patients, there are still no established treatment schemes in global practice. Many children with ASD have allergic symptoms, often in the absence of mast cell (MC) positive tests. Activation of MCs may release molecules related to inflammation and neurotoxicity, which contribute to the pathogenesis of ASD. The aim of the present paper is to enrich the current knowledge regarding the relationship between MCs and ASD by providing PPI network analysis-based data that reveal key molecules and immune pathways associated with MCs in the pathogenesis of autism. Network and enrichment analyzes were performed using receptor information and secreted molecules from activated MCs identified in ASD patients. Our analyses revealed cytokines and key marker molecules for MCs degranulation, molecular pathways of key mediators released during cell degranulation, as well as various receptors. Understanding the relationship between ASD and the activation of MCs, as well as the involved molecules and interactions, is important for elucidating the pathogenesis of ASD and developing effective future treatments for autistic patients by discovering new therapeutic target molecules.

Hydroethanolic extract of Gentiana kurroo Royle rhizome ameliorates ethanol-induced liver injury by reducing oxidative stress, inflammation and fibrogenesis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Gentiana kurroo Royle is a medicinal plant mentioned as Traymana in Ayurveda. In the folklore, it is used to cure fever, stomach ache, skin diseases and liver disorders. However, limited reports are available on the therapeutic potential of Gentiana kurroo Royle against alcohol-induced liver damage.

AIM OF THE STUDY

To assess the effectiveness of the hydroethanolic extract of Gentiana kurroo Royle rhizome (GKRE) against alcohol-induced liver injury and explore the mechanism of action.

MATERIALS AND METHODS

GKRE was characterized using UHPLC-QTOF-MS/MS. The binding affinity of the identified compound was studied in silico. In vitro studies were performed in the Huh-7 cell line. An acute oral toxicity study (2 g/kg BW) of GKRE was done in rats following OECD 420 guidelines. In the efficacy study, rats were treated with 50% ethanol (5 mL/kg BW, orally) for 4 weeks, followed by a single intraperitoneal dose of CCl4 (30%; 1 mL/kg BW) to induce liver injury. After 4th week, the rats were treated with GKRE at 100, 200 and 400 mg/kg BW doses for the next fifteen days. The biochemical and antioxidant parameters were analyzed using commercial kits and a biochemistry analyzer. Histopathology, gene and protein expressions were studied using qRT PCR and western blotting.

RESULTS

Thirteen compounds were detected in GKRE. Few compounds showed a strong interaction with the fibrotic and inflammatory proteins in silico. GKRE reduced (p < 0.05) the ethanol-induced ROS production and inflammation in Huh-7 cells. The acute oral toxicity study revealed no adverse effect of GKRE in rats at 2 g/kg BW. GKRE improved (p < 0.05) the body and liver weights in ethanol-treated rats. GKRE improved (p < 0.05) the mRNA levels of ADH, SREBP1c and mitochondrial biogenesis genes in the liver tissues. GKRE also improved (p < 0.05) the liver damage markers, lipid peroxidation and levels of antioxidant enzymes in the liver. A reduced severity (p < 0.05) of pathological changes, fibrotic tissue deposition and caspase 3/7 activity were observed in the liver tissues of GKRE-treated rats. Further, GKRE downregulated (p < 0.05) the expression of fibrotic (TGFβ, αSMA and SMADs) and inflammatory markers (TNFα, IL6, IL1β and NFκB) in the liver.

CONCLUSION

GKRE showed efficacy against alcohol-induced liver damage by inhibiting oxidative stress, apoptosis, inflammation and fibrogenesis in the liver.

Timosaponin BⅡ reduces colonic inflammation and alleviates DSS-induced ulcerative colitis by inhibiting NLRP3

ETHNOPHARMACOLOGICAL RELEVANCE

The Timosaponin BⅡ (TBⅡ) is one of the main active components of the traditional Chinese medicine Anemarrhena asphodeloides, and it is a steroidal saponin with various pharmacological activities such as anti-oxidation, anti-inflammatory and anti-apoptosis. However, its role in acute ulcerative colitis remains unexplored thus far.

AIM OF THE STUDY

This study aims to investigate the protective effect of TBⅡ against dextran sulfate sodium (DSS)-induced ulcerative colitis in mice and elucidate its underlying mechanisms.

METHODS

Wild-type (WT) and NLRP3 knockout (NLRP3-/-) mice were applied to evaluate the protective effect of TBⅡ in DSS-induced mice colitis. Pharmacological inhibition of NLRP3 or adenovirus-mediated NLRP3 overexpression in bone marrow-derived macrophages (BMDM) from WT mice and colonic epithelial HCoEpiC cells was used to assess the role of TBⅡ in LPS + ATP-induced cell model. RNA-seq, ELISA, western blots, immunofluorescence staining, and expression analysis by qPCR were performed to examine the alterations of colonic NLRP3 expression in DSS-induced colon tissues and LPS + ATP-induced cells, respectively.

RESULTS

In mice with DSS-induced ulcerative colitis, TBⅡ treatment attenuated clinical symptoms, repaired the intestinal mucosal barrier, reduced inflammatory infiltration, and alleviated colonic inflammation. RNA-seq analysis and protein expression levels demonstrated that TBⅡ could prominently inhibit NLRP3 signaling. TBⅡ-mediated NLRP3 inhibition was associated with alleviating intestinal permeability and inflammatory response via the blockage of communication between epithelial cells and macrophages, probably in an NLRP3 inhibition mechanism. However, pharmacological inhibition of NLRP3 by MCC950 or Ad-NLRP3 mediated NLRP3 overexpression significantly impaired the TBⅡ-mediated anti-inflammatory effect. Mechanistically, TBⅡ-mediated NLRP3 inhibition may be partly associated with the suppression of NF-κB, a master pro-inflammatory factor for transcriptional regulation of NLRP3 expression in the priming step. Moreover, co-treatment TBⅡ with NF-κB inhibitor BAY11-7082 partly impaired TBⅡ-mediated NLRP3 inhibition, and consequently affected the IL-1β mature and secretion. Importantly, TBⅡ-mediated amelioration was not further enhanced in NLPR3-/- mice.

CONCLUSION

TBⅡ exerted a prominent protective effect against DSS-induced colitis via regulation of alleviation of intestinal permeability and inflammatory response via the blockage of crosstalk between epithelial cells and macrophages in an NLRP3-mediated inhibitory mechanism. These beneficial effects could make TBⅡ a promising drug for relieving colitis.

Annexin A1 conveys neuroprotective function via inhibiting oxidative stress in diffuse axonal injury of rats

Diffuse axonal injury (DAI) is a critical pathological facet of traumatic brain injury (TBI). Oxidative stress plays a significant role in the progress of DAI. Annexin A1 (AnxA1) has been demonstrated to benefit from recovery of neurofunctional outcomes after TBI. However, whether AnxA1 exhibits neuronal protective function by modulating oxidative stress in DAI remains unknown. Expression of AnxA1 was evaluated via real-time PCR and western blotting in rat brainstem after DAI. The neurological effect of AnxA1 following DAI through quantification of modified neurologic severity score (mNSS) was compared between wild-type and AnxA1-knockout rats. Brain edema and neuronal apoptosis, as well as expression of oxidative factors and inflammatory cytokines, were analyzed between wild-type and AnxA1 deficiency rats after DAI. Furthermore, mNSS, oxidative and inflammatory cytokines were assayed after timely administration of recombinant AnxA1 for DAI rats. In the brainstem of DAI, the expression of AnxA1 remarkably increased. Ablation of AnxA1 increased the mNSS score and brain water content of rats after DAI. Neuron apoptosis in the brainstem after DAI was exaggerated by AnxA1 deficiency. In addition, AnxA1 deficiency significantly upregulated the level of oxidative and inflammatory factors in the brainstem of DAI rats. Moreover, mNSS decreased by AnxA1 treatment in rats following DAI. Expression of oxidative and inflammatory molecules in rat brainstem subjected to DAI inhibited by AnxA1 administration. AnxA1 exhibited neuronal protective function in the progression of DAI mainly dependent on suppressing oxidative stress and inflammation.

Role of sulfatide-reactive vNKT cells in promoting lung Treg cells via dendritic cell modulation in asthma models

Our previous studies have showed that sulfatide-reactive type II NKT (i.e. variant NKT, vNKT) cells inhibit the immunogenic maturation during the development of mature lung dendritic cells (LDCs), leading todeclined allergic airway inflammation in asthma. Nonetheless, the specific immunoregulatory roles of vNKT cells in LDC-mediated Th2 cell responses remain incompletely understood. Herein, we found that administration of sulfatide facilitated the generation of CD4+FoxP3+ regulatory T (Treg) cells in the lungs of wild-type mice, but not in CD1d-/- and Jα18-/- mice, after ovalbumin or house dust mite exposure. This finding implies that the enhancement of lung Treg cells by sulfatide requires vNKT cells, which dependent on invariant NKT (iNKT) cells. Furthermore, the CD4+FoxP3+ Treg cells induced by sulfatide-reactive vNKT cells were found to be associated with PD-L1 molecules expressed on LDCs, and this association was dependent on iNKT cells. Collectively, our findings suggest that in asthma-mimicking murine models, sulfatide-reactive vNKT cells facilitate the generation of lung Treg cells through inducing tolerogenic properties in LDCs, and this process is dependent on the presence of lung iNKT cells. These results may provide a potential therapeutic approach to treat allergic asthma.

mm9_circ_014683 regulates microglia polarization through canonical NFκB signaling pathway in diabetic retinopathy

Diabetic retinopathy (DR) is still the major cause of visual loss in working-aged people, one of the critical pathological processes are retinal microglia-mediated inflammation. Our previous study demonstrated that enhanced M1 microglial polarization was involved in retinal inflammation in DR, but the detailed mechanism needs further investigation. Circular RNAs (circRNAs) are important kind of noncoding RNAs involved in the regulation of various cell biological processes. Herein, the circRNA expression profiles of BV2 mouse microglia treated with or without glucose were detected, and a total of 347 differentially expressed circRNAs were identified in glucose-treated BV2 cells. The key circRNA mm9_circ_014683 increased after glucose stimulation. Inhibiting or overexpressing mm9_circ_014683 showed no effect on the proliferation and apoptosis of microglia. Inhibiting mm9_circ_014683 impeded M1 polarization and promoted M2 polarization, and overexpressing mm9_circ_014683 showed the opposite effect. A total of 216 differentially expressed genes were identified in mm9_circ_014683-knockdown BV2 cells, which were enriched in several signaling pathways, including the NFκB signaling pathway. Moreover, mm9_circ_014683 positively regulated the canonical, NFκB signaling pathway. Besides, mm9_circ_014683 was highly expressed in the retinal microglia of diabetic mice, and intraocular injection of Lv-circRNA inhibited M1 but enhanced M2 retinal microglial polarization. In conclusion, mm9_circ_014683 regulates microglial polarization through the canonical NFκB signaling pathway in diabetic retinopathy. This study may provide insight into the pathogenesis and treatment of DR.

Perturbed liver gene zonation in a mouse model of non-alcoholic steatohepatitis

Liver zonation characterizes the separation of metabolic pathways along the lobules and is required for optimal hepatic function. Wnt signaling is a master regulator of spatial liver zonation. A perivenous-periportal Wnt activity gradient orchestrates metabolic zonation by activating gene expression in perivenous hepatocytes, while suppressing gene expression in their periportal counterparts. However, the understanding as to the liver gene zonation and zonation regulators in diseases is limited. Non-alcoholic steatohepatitis (NASH) is a chronic liver disease characterized by fat accumulation, inflammation, and fibrosis. Here, we investigated the perturbation of liver gene zonation in a mouse NASH model by combining spatial transcriptomics, bulk RNAseq and in situ hybridization. Wnt-target genes represented a major subset of genes showing altered spatial expression in the NASH liver. The altered Wnt-target gene expression levels and zonation spatial patterns were in line with the up regulation of Wnt regulators and the augmentation of Wnt signaling. Particularly, we found that the Wnt activator Rspo3 expression was restricted to the perivenous zone in control liver but expanded to the periportal zone in NASH liver. AAV8-mediated RSPO3 overexpression in controls resulted in zonation changes, and further amplified the disturbed zonation of Wnt-target genes in NASH, similarly Rspo3 knockdown in Rspo3+/- mice resulted in zonation changes of Wnt-target genes in both chow and HFD mouse. Interestingly, there were no impacts on steatosis, inflammation, or fibrosis NASH pathology from RSPO3 overexpression nor Rspo3 knockdown. In summary, our study demonstrated the alteration of Wnt signaling in a mouse NASH model, leading to perturbed liver zonation.

Expression of Siglec-9 in peripheral blood neutrophils was increased and associated with disease severity in patients with AECOPD

BACKGROUND

The pathogenesis and treatment strategies for chronic obstructive pulmonary disease (COPD) require further exploration. Abnormal neutrophil inflammation and the overexpression of neutrophil extracellular traps (NETs) are closely associated with acute exacerbations of COPD (AECOPD). Siglec-9, a specific receptor expressed on neutrophils that inhibits their function, prompted us to investigate its relationship with NETs found in induced sputum and the severity of the disease.

METHODS

We collected clinical data from patients with AECOPD and assessed the expression of Siglec-9 in peripheral blood neutrophils and the presence of NETs in induced sputum. We then observed the correlation between Siglec-9, the inflammatory response, and the severity of AECOPD.

RESULTS

We observed an increase in the expression of Siglec-9 in the peripheral blood neutrophils of patients with AECOPD. Concurrently, these patients exhibited more severe clinical symptoms, higher systemic inflammation levels, and a reduced quality of life compared to those with induced sputum NET expression. Further subgroup analysis of AECOPD patients with high Siglec-9 expression revealed worsened quality of life and more severe inflammation, particularly in indicators such as the BODE index, CRP, peripheral blood neutrophil count, IL-6, IL-8, TNF-α expression, and others. Furthermore, we noted a significant increase in NET-specific expression in the sputum of patients with high Siglec-9 expression levels. In comparison to patients with low Siglec-9 expression, those with high expression experienced more systemic inflammatory reactions and a lower quality of life. Correlation analysis of the aforementioned indicators revealed that the expression ratio of Siglec-9 in the peripheral blood of patients correlated with lung function, quality of life, and NETs in the induced sputum of patients with AECOPD.

CONCLUSION

The increased expression of Siglec-9 in peripheral blood neutrophils of AECOPD patients leads to elevated NET expression in induced sputum, exacerbating the systemic inflammatory response and worsening lung function and quality of life in these patients.

MM165 - A Small Hybrid Molecule Modulates the Kynurenine Pathway and Attenuates Lipopolysaccharide-Induced Memory Deficits and Inflammation

Cognitive dysfunctions are now recognized as core symptoms of various psychiatric disorders e.g., major depressive disorder. Sustained immune activation may leads to cognitive dysfunctions. Proinflammatory cytokines shunt the metabolism of tryptophan towards kynurenine and quinolinic acid may accumulate at toxic concentrations. This acid triggers an increase in neuronal nitric oxide synthase function and promotes oxidative stress. The searching for small molecules that can regulate tryptophan metabolites produced in the kynurenic pathway has become an important goal in developing treatments for various central nervous system diseases with an inflammatory component. Previously we have identified a small hybrid molecule - MM165 which significantly reduces depressive-like symptoms caused by inflammation induced by lipopolysaccharide administration. In the present study, we investigated whether this compound would mitigate cognitive deficits induced by lipopolysaccharide administration and whether treatment with it would affect the plasma or brain levels of quinolinic acid and kynurenic acid. Neuroinflammation was induced in rats by administering lipopolysaccharide at a dose of 0.5 mg/kg body weight for 10 days. We conducted two tests: novel object recognition and object location, to assess the effect on memory impairment in animals previously treated with lipopolysaccharide. In plasma collected from rats, the concentrations of C-reactive protein and tumor necrosis factor alfa were determined. The concentrations of kynurenic acid and quinolinic acid were determined in plasma and homogenates obtained from the cerebral cortex of rats. Interleukin 6 in the cerebral cortex of rats was determined. Additionally, the body and spleen mass and spontaneous activity were measured in rats. Our study shows that MM165 may mitigate cognitive deficits induced by inflammation after administration of lipopolysaccharide and alter the concentrations of tryptophan metabolites in the brain. Compounds exhibiting a mechanism of action analogous to that of MM165 may serve as foundational structures for the development of a new class of antidepressants.

Boric Acid Alleviates Gastric Ulcer by Regulating Oxidative Stress and Inflammation-Related Multiple Signaling Pathways

Oxidative stress and inflammation have pivotal roles in gastric ulcer development caused by alcohol consumption. Trace element boric acid taken into the human and animal body from dietary sources displays strong antioxidant and anti-inflammatory functions. However, the mechanisms underlying these actions of boric acid remain unclear, and its effectiveness in preventing gastric lesions is unknown. Therefore, the present study was undertaken to evaluate the protective effects of boric acid in alcohol-induced gastric ulcer and elucidate its potential mechanisms. Gastric ulcer was induced by 75% oral ethanol administration in rats, and the effectiveness of prophylactic boric acid treatment at 100 mg/kg concentration was assessed by histopathological examination, ELISA assay and qRT-PCR. Gross macroscopic and histopathological evaluations revealed that boric acid alleviated gastric mucosal lesions. Boric acid decreased reactive oxygen species (ROS) and malondialdehyde (MDA) concentration and the overall oxidation state of the body while improving antioxidant status. It reduced the concentration of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). The mRNA expression of JAK2 and STAT3 was decreased while the expression of AMPK was increased with boric acid pretreatment. Moreover, Sema3A and PlexinA1 levels were elevated upon boric acid pretreatment, and homocysteine levels were reduced. Our results demonstrated that boric acid protects gastric mucosa from ethanol-induced damage by regulating oxidative and inflammatory responses. In addition, our findings suggested that the gastroprotective activity of boric acid could be attributed to its regulatory function in the IL-6/JAK2/STAT3 signaling modulated by AMPK and that Sema3A/PlxnA1 axis and homocysteine are potentially involved in this process.

Hyperactivation of succinate dehydrogenase promotes pyroptosis of macrophage via ROS-induced GSDMD oligomerization in acute liver failure

Acute liver failure (ALF) is a life-threatening disease with high mortality. Given excessive inflammation is one of the major pathogenesis of ALF, candidates targeting inflammation could be beneficial in the condition. Now the effect of hyperactivated succinate dehydrogenase (SDH) on promoting inflammation in lipopolysaccharide (LPS)-treated macrophages has been studied. However, its role and mechanism in ALF is not well understood. Here intraperitoneal injection of D-galactosamine and LPS was conducted in male C57BL/6 J mice to induce the ALF model. Dimethyl malonate (DMM), which inhibited SDH activity, was injected intraperitoneally 30 min before ALF induction. Macrophage pyroptosis was induced by LPS plus adenosine triphosphate (ATP). Pyroptosis-related molecules and proteins including GSDMD oligomer were examined by ELISA and western blot techniques, respectively. ROS production was assessed by fluorescence staining. The study demonstrated SDH activity was increased in liver macrophages from ALF mice. Importantly, DMM administration inhibited ROS, IL-1β, and pyroptosis-associated proteins levels (NLRP3, cleaved caspase-1, GSDMD-N, and GSDMD oligomers) both in the ALF model and in macrophages stimulated with LPS plus ATP. In vitro, ROS promoted pyroptosis by facilitating GSDMD oligomerization. Additionally, when ROS levels were increased through the addition of H2O2 to the DMM group, the levels of GSDMD oligomers were reverted. In conclusion, SDH hyperactivation promotes macrophage pyroptosis by ROS-mediated GSDMD oligomerization, suggesting that targeting this pathway holds promise as a strategy for treating ALF and other inflammatory diseases.

Adipocyte-Specific Hnrnpa1 Knockout Aggravates Obesity-Induced Metabolic Dysfunction via Upregulation of CCL2

Heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1) is involved in lipid and glucose metabolism via mRNA processing. However, whether and how HNRNPA1 alters adipocyte function in obesity remain obscure. Here, we found that the obese state downregulated HNRNPA1 expression in white adipose tissue (WAT). The depletion of adipocyte HNRNPA1 promoted markedly increased macrophage infiltration and expression of proinflammatory and fibrosis genes in WAT of obese mice, eventually leading to exacerbated insulin sensitivity, glucose tolerance, and hepatic steatosis. Mechanistically, HNRNPA1 interacted with Ccl2 and regulated its mRNA stability. Intraperitoneal injection of CCL2-CCR2 signaling antagonist improved adipose tissue inflammation and systemic glucose homeostasis. Furthermore, HNRNPA1 expression in human WAT was negatively correlated with BMI, fat percentage, and subcutaneous fat area. Among individuals with 1-year metabolic surgery follow-up, HNRNPA1 expression was positively related to percentage of total weight loss. These findings identify adipocyte HNRNPA1 as a link between adipose tissue inflammation and systemic metabolic homeostasis, which might be a promising therapeutic target for obesity-related disorders.

ARTICLE HIGHLIGHTS

Tryptophan metabolism and kynurenine metabolites in cancer: systemic nutritional and metabolic implications

PURPOSE OF REVIEW

To describe the role of Tryptophan (Trp) metabolism and Kynurenine (Kyn) metabolites in nutritional and metabolic changes in cancer.

RECENT FINDINGS

Trp is in part utilized for protein and neurotransmitters biosynthesis, but more than 95% is implicated in Kyn pathways. In this molecular cascade, metabolites are produced with distinct biological activities regulating the immune response and neurotransmission with potential implications in malnutrition/cachexia during cancer. Immune dysfunction is a phenomenon occurring during cancer and malnutrition. Kyn metabolites regulate lymphocytes activity and recent data in animals showed that the inhibition of indoleamine-2,3-dioxygenase (IDO) via 1-methyl-tryptophan determines partial amelioration of inflammation, but no positive effects on the preservation of muscularity were observed. Kynurenines seem to contribute to muscle catabolism via NAD+ biosynthesis and ROS generation. Trp metabolism via the serotonin biosynthesis is involved in appetite control in cancer. Moreover, kynurenines have a role in determining fatigue in conditions associated with inflammation.

SUMMARY

Trp metabolism has implications in immune and energy balance in cancer. The modulation of Trp and kynurenines have impact on central nervous system mechanisms, including appetite, fatigue, and muscle wasting/cachexia. Research focusing on these clinical implications will open new scenario for therapeutic interventions aimed at counteracting nutritional derangements in cancer.

Eucalyptol regulates Nrf2 and NF-kB signaling and alleviates gentamicin-induced kidney injury in rats by downregulating oxidative stress, oxidative DNA damage, inflammation, and apoptosis

Gentamicin, an aminoglycoside antibiotic, is nowadays widely used in the treatment of gram-negative microorganisms. The antimicrobial, anti-inflammatory, and antioxidant activities of eucalyptol, a type of saturated monoterpene, have been reported in many studies. The aim of this study was to examine the possible effects of eucalyptol on gentamicin-induced renal toxicity. A total of 32 rats were divided into 4 groups; Control (C), Eucalyptol (EUC), Gentamicin (GEN), and Gentamicin + Eucalyptol (GEN + EUC). In order to induce renal toxicity, 100 mg/kg gentamicin was administered intraperitoneally (i.p.) for 10 consecutive days in the GEN and GEN + EUC groups. EUC and GEN + EUC groups were given 100 mg/kg orally of eucalyptol for 10 consecutive days. Afterwards, rats were euthanized and samples were taken and subjected to histopathological, biochemical, immunohistochemical, and real-time PCR examinations. The blood urea nitrogen (BUN) and creatinine (CRE) levels were significantly decreased in the GEN + EUC group (0.76 and 0.69-fold, respectively) compared to the GEN group. The glutathione peroxidase (GPx) and catalase (CAT) activities were significantly increased in the GEN + EUC group (1.35 and 2.67-fold, respectively) compared to the GEN group. In GEN group, Nuclear factor kappa B (NF-kB), Interleukin 1-beta (IL-1β), Inducible nitric oxide synthase (iNOS), Tumor necrosis factor-α (TNF-α), Caspase-3, 8-Hydroxy-2'-deoxyguanosine (8-OHdG) and Nuclear factor erythroid 2-related factor (Nrf2) expression levels were found to be quite irregular. GEN + EUC group decreased the expressions of NF-kB, IL-1β, iNOS, TNF-α, Caspase-3, and 8-OHdG (0.55, 0.67, 0.54, 0.54, 0.63 and 0.67-fold, respectively), while it caused increased expression of Nrf2 (3.1 fold). In addition, eucalyptol treatment ameliorated the histopathological changes that occurred with gentamicin. The results of our study show that eucalyptol has anti-inflammatory, antioxidative, antiapoptotic, nephroprotective, and curative effects on gentamicin-induced nephrotoxicity.

The Effect of Parenteral Selenium Therapy on Serum Concentration of Inflammatory Mediators: a Systematic Review and Dose-Response Meta-Analysis of Randomized Clinical Trials

Selenium can protect against inflammation through its incorporation in selenoenzymes; therefore, in this study, we assessed the effect of parenteral selenium on C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) through a systematic review and meta-analysis on randomized controlled trials (RCTs). A systematic search was performed in the databases, including PubMed, Scopus, Cochrane, clinicaltrials.gov, and ISI Web of Science, up to October 2022, with no limitation in study location or publication time. We calculated the effect size by the mean change from baseline in serum concentration of selected inflammatory mediators and their standard deviations. DerSimonian and Laird random effects model was used to estimate the heterogeneity and summary of the overall effects. Included studies in this systematic review and meta-analysis were 10 and 8 RCTs, respectively. Our results revealed parenteral selenium significantly decreased serum IL-6 (Weighted Mean Difference (WMD) = -3.85 pg/ml; 95% confidence interval (CI) = -7.37, -0.34 pg/ml; p = 0.032) but did not significantly change serum levels of CRP (WMD = 4.58 mg/L; 95% CI = -6.11, 15.27 mg/L; P = 0.401) compared to the comparison groups. According to our results, parenteral selenium supplementation might reduce serum levels of inflammatory mediators.

METTL3-deficiency m6A-dependently degrades MALAT1 to suppress NLRP3-mediated pyroptotic cell death and inflammation in Mycobacterium tuberculosis (H37Ra strain)-infected mouse macrophages

Mycobacterium tuberculosis (Mtb)-infected macrophages aggravated the development of pulmonary tuberculosis, but its detailed molecular mechanisms are still largely unknown. Here, the mouse primary peritoneal macrophages were infected with the attenuated strain of Mtb H37Ra, and we firstly verified that targeting a novel METTL3/N6-Methyladenosine (m6A)/LncRNA MALAT1/miR-125b/TLR4 axis was effective to suppress pyroptotic cell death in the Mtb-infected macrophages. Specifically, through performing Real-Time qPCR and Western Blot analysis, we validated that METTL3, LncRNA MALAT1 and TLR4 were elevated, whereas miR-125b and the anti-oxidant agents (Nrf2 and HO-1) were downregulated in Mtb-infected mouse macrophages. In addition, functional experiments confirmed that both ROS scavenger NAC and METTL3-ablation downregulated NLRP3, GSDMD-C, cleaved Caspase-1 and ASC to restrain pyroptotic cell death and decreased the expression levels of IL-1β, IL-18, IL-6 and TNF-α to restrain inflammatory cytokines expression in Mtb-infected macrophages. Next, METTL3-ablation induced m6A-demethylation and instability in LncRNA MALAT1, and low-expressed LncRNA MALAT1 caused TLR4 downregulation through sponging miR-125b, resulting in the inactivation of NLRP3 inflammasome. Finally, silencing of METTL3-induced protective effects in Mtb-infected macrophages were all abrogated by overexpressing LncRNA MALAT1 and downregulating miR-125b. Thus, we concluded that targeting METTL3-mediated m6A modifications suppressed Mtb-induced pyroptotic cell death in mouse macrophages, and the downstream LncRNA MALAT1/miR-125b/TLR4 axis played critical role in this process.

Resveratrol prevents cognitive impairment and hippocampal inflammatory response induced by lipopolysaccharide in a mouse model of chronic neuroinflammation

BACKGROUND

Neurodegenerative disorders are associated with chronic neuroinflammation, which contributes to their pathogenesis and progression. Resveratrol (RSV) is a polyphenolic compound with strong antioxidant and anti-inflammatory properties. In the present study, we investigated whether RSV could protect against cognitive impairment and inflammatory response in a mouse model of chronic neuroinflammation induced by lipopolysaccharide (LPS).

METHOD

Mice received oral RSV (30 mg/kg) or vehicle for two weeks, and injected with LPS (0.75 mg/kg) or saline daily for the last seven days. After two weeks, mice were subjected to behavioral assessments using the Morris water maze and Y-maze. Moreover, mRNA expression of several inflammatory markers, neuronal loss, and glial density were evaluated in the hippocampus of treated mice.

RESULTS

Our findings showed that RSV treatment effectively improved spatial and working memory impairments induced by LPS. In addition, RSV significantly reduced hippocampal glial densities and neuronal loss in LPS-injected mice. Moreover, RSV treatment suppressed LPS-induced upregulation of NF-κB, IL-6, IL-1β, and GFAP in the hippocampus of treated mice.

CONCLUSION

Taken together, our results highlight the detrimental effect of systemic inflammation on the hippocampus and the potential of natural products with anti-inflammatory effects to counteract this impact.

Velvet antler polypeptide (VAP) protects against cerebral ischemic injury through NF-κB signaling pathway in vitro

OBJECTIVE

Velvet antler polypeptide (VAP) has been shown to play important roles in the immune and nervous systems. The purpose of this study was to investigate the protective effects of VAP on cerebral ischemic injury with the involvement of NF-κB signaling pathway in vitro.

MATERIALS AND METHODS

PC-12 cells stimulated by oxygen-glucose deprivation/reperfusion (OGD/R) was used to mimic cerebral ischemic injury in vitro. The levels of ROS, SOD, and intracellular concentrations of Ca2+ were measured by the relevant kits. Meanwhile, the expressions of inflammatory cytokines (IL-6, IL-1β, and TNF-α) were determined by ELISA kit assay. In addition, MTT, EdU, and flow cytometry assays were used to measure the cell proliferation and apoptosis. Besides which, the related proteins of NF-κB signaling pathway were measured by western blotting assay.

RESULTS

VAP alleviated cerebral ischemic injury by reducing OGD/R-induced oxidative stress, inflammation, and apoptosis in PC-12 cells in a time dependent manner. Mechanistically, VAP inhibited the levels of p-p65 and p-IkB-α in a time dependent manner, which was induced by OGD/R operation. Moreover, NF-κB agonist diprovocim overturned the suppression effects of VAP on OGD/R-induced oxidative stress, inflammation, and apoptosis in PC-12 cells.

CONCLUSIONS

The results demonstrate that VAP may alleviate cerebral ischemic injury by suppressing the activation of NF-κB signaling pathway.

Regulatory T cells: Supporting lung homeostasis and promoting resolution and repair after lung injury

Regulatory T cells, characterized by their expression of the transcription factor Forkhead box P3, are indispensable in maintaining immune homeostasis. The respiratory system is constantly exposed to many environmental challenges, making it susceptible to various insults and infections. Regulatory T cells play essential roles in maintaining homeostasis in the lung and promoting repair after injury. Regulatory T cell function dysregulation can lead to inflammation, tissue damage, or aberrant repair. Research on regulatory T cell mechanisms in the lung has unveiled their influence on lung inflammation and repair mechanisms. In this review, our goal is to highlight the advances in regulatory T cell biology with respect to lung injury and resolution. We further provide a perspective that a deeper understanding of regulatory T cell interactions in the lung microenvironment in health and disease states offers opportunities for therapeutic interventions as treatments to promote lung health.

The reduction of microglial efferocytosis is concomitant with depressive-like behavior in CUMS-treated mice

BACKGROUND

Microglial efferocytosis plays a crucial role in facilitating and sustaining homeostasis in the central nervous system, and it is involved in neuropsychiatric disorders. How microglial efferocytosis is affected under the condition of major depressive disorder (MDD) remains elusive. In this study, we hypothesized that microglial efferocytosis in the hippocampus is impaired in the chronic unpredicted mild stress (CUMS) model of MDD, which is involved in the development of MDD.

METHOD

Depressive-like behavior in adult male mice was induced by CUMS and confirmed by behavioral tests. Microglial efferocytosis was evaluated using immunofluorescence staining of hippocampal slices and primary microglia co-cultured with apoptotic cells. The protein and mRNA levels of phagocytosis-related molecules and inflammation-related cytokines were detected using western blotting and RT-qPCR, respectively. Annexin V was injected to mimic impairment of microglial efferocytosis. TREM2-siRNA was further used on primary microglia to examine efferocytosis-related signaling pathways.

RESULTS

Microglia were activated and the expression of proinflammatory cytokines was increased in CUMS mice, while microglial efferocytosis and efferocytosis-related molecules were decreased. Inhibition of the TREM2/Rac1 pathway impaired microglial efferocytosis. Annexin V injection inhibited microglial efferocytosis, increased inflammation in the hippocampus and depressive-like behavior.

LIMITATIONS

The potential antidepressant effect of the upregulation of the TREM2/Rac1 pathway was not evaluated.

CONCLUSIONS

Impairment of microglial efferocytosis is involved in the development of depressive-like behavior, with downregulation of the TREM2/Rac1 pathway and increased inflammation. These results may increase our understanding of the pathophysiological mechanisms associated with MDD and provide novel targets for therapeutic interventions.

STAT4 targets KISS1 to inhibit the oxidative damage, inflammation and neuronal apoptosis in experimental PD models by inactivating the MAPK pathway

BACKGROUND

Oxidative stress and neuroinflammation are proven to play critical roles in the pathogenesis of Parkinson's disease (PD). As reported, patients with PD have lower level of STAT4 compared with healthy subjects. However, the biological functions and mechanisms of STAT4 in PD pathogenesis remain uncertain. This study aimed to investigate the roles and related mechanisms of STAT4 in PD development.

METHODS

The intraperitoneal injection of MPTP (20 mg/kg) dissolved in physiological saline was performed to mimic PD-like conditions in vivo. MPP + solution was prepared for cell model of PD. Cell viability was measured by CCK-8. Griess reaction was conducted to measure NO concentrations. The mRNA and protein levels were evaluated by RT-qPCR and western blotting. ROS generation was assessed by DCFH-DA. The levels of inflammatory cytokines were measured by ELISA. Cell apoptosis was examined by flow cytometry and western blotting. Moreover, the SH-SY5Y cells were treated with conditioned medium from LPS-stimulated microglia and subjected to CCK-8 assays and ELISA. Mechanistically, CHIP assays and luciferase reporter assays were performed to verify the binding relationship between KISS1 and STAT4. For in vivo analysis, the histological changes of midbrain tissues of mice were determined by hematoxylin and eosin staining. The expression of tyrosine hydroxylase (TH) was detected by immunohistochemistry staining. Iba-1 positive microglial cells in the striatum were assessed by immunofluorescence staining.

RESULTS

For in vitro analysis, STAT4 level was downregulated after MPP+ treatment, and STAT4 upregulation inhibited the oxidative damage, inflammation and apoptosis in SH-SY5Y cells. STAT4 bound at +215-228 region of KISS1, and KISS1 upregulation counteracted the protection of STAT4 upregulation against cell damage. Moreover, STAT4 upregulation inhibited cell viability loss and inflammation induced by conditioned medium from LPS-treated microglia, whereas KISS1 upregulation had the opposite effect. For in vivo analysis, the protective effects of STAT4 upregulation against inflammatory response, oxidative stress, dopaminergic neuronal loss and microglia activation were attenuated by KISS1 upregulation. Moreover, the inactivation of MAPK pathway caused by STAT4 upregulation was reversed by KISS1 upregulation, and MAPK inhibition attenuated the MPP+-induced inflammation, oxidative stress and apoptosis in SH-SY5Y cells.

CONCLUSION

STAT4 inhibits KISS1 to attenuate the oxidative damage, inflammation and neuronal apoptosis in PD by inactivating the MAPK pathway.

The emergence of inflammatory microglia during gut inflammation is not affected by FFAR2 expression in intestinal epithelial cells or peripheral myeloid cells

Gut inflammation can trigger neuroinflammation and is linked to mood disorders. Microbiota-derived short-chain fatty acids (SCFAs) can modulate microglia, yet the mechanism remains elusive. Since microglia do not express free-fatty acid receptor (FFAR)2, but intestinal epithelial cells (IEC) and peripheral myeloid cells do, we hypothesized that SCFA-mediated FFAR2 activation within the gut or peripheral myeloid cells may impact microglia inflammation. To test this hypothesis, we developed a tamoxifen-inducible conditional knockout mouse model targeting FFAR2 exclusively on IEC and induced intestinal inflammation with dextran sodium sulfate (DSS), a well-established colitis model. Given FFAR2's high expression in myeloid cells, we also investigated its role by selectively deleting it in these populations of cells. In an initial study, male and female wild-type mice received 0 or 2% DSS for 5d and microglia were isolated 3d later to assess inflammatory status. DSS induced intestinal inflammation and upregulated inflammatory gene expression in microglia, indicating inflammatory signaling via the gut-brain axis. Despite the lack of significant effects of sex in the intestinal phenotype, male mice showed higher microglial inflammatory response than females. Subsequent studies using FFAR2 knockout models revealed that FFAR2 expression in IECs or immune myeloid cells did not affect DSS-induced colonic pathology (i.e. clinical and histological scores and colon length), or colonic expression of inflammatory genes. However, FFAR2 knockout led to an upregulation of several microglial inflammatory genes in control mice and downregulation in DSS-treated mice, suggesting that FFAR2 may constrain neuroinflammatory gene expression under healthy homeostatic conditions but may permit it during intestinal inflammation. No interactions with sex were observed, suggesting sex does not play a role on FFAR2 potential function in gut-brain communication in the context of colitis. To evaluate the role of FFAR2 activated by microbiota-derived SCFAs, we employed the same knockout and DSS models adding fermentable dietary fiber (0 or 2.5% inulin for 8 wks). Despite no genotype or fiber main effects, contrary to our hypothesis, inulin feeding augmented DSS-induced inflammation and signs of colitis, suggesting context-dependent effects of fiber. These findings highlight microglial involvement in colitis-associated neuroinflammation and advance our understanding of FFAR2's role in the gut-brain axis. Although not integral, we observed that the role of FFAR2 differs between homeostatic and inflammatory conditions, underscoring the need to consider different inflammatory conditions and disease contexts when investigating the role of FFAR2 and SCFAs in the gut-brain axis.

IL-4 activates ULK1/Atg9a/Rab9 in asthma, NLRP3 inflammasomes, and Golgi fragmentation by increasing autophagy flux and mitochondrial oxidative stress

During asthma, there is an intensification of pulmonary epithelial inflammation, mitochondrial oxidative stress, and Golgi apparatus fragmentation. However, the underlying mechanism remains largely unknown. Therefore, this study investigated the roles of ULK1, Atg9a, and Rab9 in epithelial inflammation, mitochondrial oxidative stress, and Golgi apparatus fragmentation. We found that ULK1 gene knockout reduced the infiltration of inflammatory cells, restored the imbalance of the Th1/Th2 ratio, and inhibited the formation of inflammatory bodies in the lung tissue of house dust mite-induced asthma mice. Moreover, we demonstrated that Atg9a interacted with ULK1 at S467. ULK1 phosphorylated Atg9a at S14. Treatment with ULK1 activator (LYN-1604) and ULK1 inhibitor (ULK-101) respectively promoted and inhibited inflammasome activation, indicating that the activation of inflammasome induced by house dust mite in asthma mice is dependent on ULK1. For validation of the in vivo results, we then used a lentivirus containing ULK1 wild type and ULK1-S467A genes to infect Beas-2b-ULK1-knockout cells and establish a stable cell line. The results suggest that the ULK1 S467 site is crucial for IL-4-induced inflammation and oxidative stress. Experimental verification confirmed that Atg9a was the superior signaling pathway of Rab9. Interestingly, we found for the first time that Rab9 played a very important role in inflammation-induced fragmentation of the Golgi apparatus. Inhibiting the activation of the ULK1/Atg9a/Rab9 signaling pathways can inhibit Golgi apparatus fragmentation and mitochondrial oxidative stress in asthma while reducing the production of NLRP3-mediated pulmonary epithelial inflammation.

Proteomic study of gamma-oryzanol preventive effect on a diet-induced non-alcoholic fatty liver disease model

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease associated with obesity and diabetes prevalence. The use of natural compounds has become an attractive approach to prevent NAFLD and its progression. Gamma-oryzanol (Orz) is a natural compound whose beneficial effects on chronic metabolic diseases have been reported. Therefore, we aimed to investigate the preventive effect of Orz on the hepatic proteome in a diet induced NAFLD model. Wistar rats were randomly distributed into three experimental groups (n=6/group) according to the diet received for 30 weeks: Control group, high sugar-fat (HSF) group, and HSF+Orz group. The isolated Orz was added to the chow at the dose of 0.5% (w/w). We evaluated the nutritional profile, characterized the presence of steatosis through histological analysis, triglyceride content in liver tissue and hepatic inflammation. Next, we performed label-free quantitative proteomics of hepatic tissue. Network analysis was performed to describe involved protein pathways. NAFLD induction was characterized by the presence of hepatic steatosis. Orz prevented lipid accumulation. The compound prevented alterations of the hepatic proteome, highlighted by the modulation of lipid metabolism, inflammation, oxidative stress, xenobiotic metabolism, and the sirtuin signaling pathway. It was possible to identify key altered pathways of NAFLD pathophysiology modulated by Orz which may provide insights into NAFLD treatment targets.

PRMT6 deficiency or inhibition alleviates neuropathic pain by decreasing glycolysis and inflammation in microglia

Microglia induced chronic inflammation is the critical pathology of Neuropathic pain (NP). Metabolic reprogramming of macrophage has been intensively reported in various chronic inflammation diseases. However, the metabolic reprogramming of microglia in chronic pain remains to be elusive. Here, we reported that immuno-metabolic markers (HIF-1α, PKM2, GLUT1 and lactate) were related with increased expression of PRMT6 in the ipsilateral spinal cord dorsal horn of the chronic construction injury (CCI) mice. PRMT6 deficiency or prophylactic and therapeutic intrathecal administration of PRMT6 inhibitor (EPZ020411) ameliorated CCI-induced NP, inflammation and glycolysis in the ipsilateral spinal cord dorsal horn. PRMT6 knockout or knockdown inhibited LPS-induced inflammation, proliferation and glycolysis in microglia cells. While PRMT6 overexpression exacerbated LPS-induced inflammation, proliferation and glycolysis in BV2 cells. Recent research revealed that PRMT6 could interact with and methylate HIF-1α, which increased HIF-1α protein stability. In sum, increased expression of PRMT6 exacerbates NP progress by increasing glycolysis and neuroinflammation through interacting with and stabilizing HIF-1α in a methyltransferase manner, which outlines novel pathological mechanism and drug target for NP.

SNHG14 Elevates NFAT5 Expression Through Sequestering miR-375-3p to Promote MPP + -Induced Neuronal Apoptosis, Inflammation, and Oxidative Stress in Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons. LncRNA small nucleolar RNA host gene 14 (SNHG14) was found to promote neuron injury in PD. Here, we investigated the mechanisms of SNHG14 in PD process. In vivo or in vitro PD model was established by using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mice or 1-methyl-4-phenylpyridinium (MPP +)-stimulated SK-N-SH cells. The expression of genes and proteins was measured by qRT-PCR and Western blot. In vitro assays were conducted using ELISA, CCK-8, colony formation, EdU, flow cytometry, and Western blot assays, respectively. The oxidative stress was evaluated by determining the production of superoxide dismutase (SOD) and malondialdehyde (MDA). The direct interactions between miR-375-3p and NFAT5 (Nuclear factor of activated T-cells 5) or SNHG14 was verified using dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. SNHG14 and NFAT5 were elevated, while miR-375-3p was decreased in MPTP-mediated PD mouse model and MPP + -induced SK-N-SH cells. Knockdown of SNHG14 or NFAT5, or overexpression of miR-375-3p reversed MPP + -induced neuronal apoptosis, inflammation, and oxidative stress. Mechanistically, SNHG14 directly bound to miR-375, which targeted NFAT5. Inhibition of miR-375-3p abolished the inhibitory activity of SNHG14 knockdown on MPP + -evoked neuronal damage. Besides that, NFAT5 up-regulation counteracted the effects of miR-375-3p on MPP + -mediated neuronal damage. SNHG14 contributed to MPP + -induced neuronal injury by miR-375/NFAT5 axis, suggesting a new insight into the pathogenesis of PD.