Sodium butyrate inhibits activation of ROS/NF-κB/NLRP3 signaling pathway and angiogenesis in human retinal microvascular endothelial cells

BACKGROUND

To determine the impact of sodium butyrate on the activation of the reactive oxygen species (ROS)/nuclear factor kappa B (NF-κB)/NLR family pyrin domain containing 3 (NLRP3) signaling pathway and angiogenesis in human retinal microvascular endothelial cells (HRMECs) caused by high glucose (HG).

METHODS

HRMECs were grown for 24 h or 72 h in HG solution (30 mmol/L D-glucose) with 5 mM NaB. Using Cell Counting Kit-8, the effects of HG and NaB levels on the viability of HRMECs were examined. Using various kits, intracellular ROS levels, lactate dehydrogenase (LDH), and Malondialdehyde (MDA) in cell supernatants were measured. Western blot, Immunofluorescence, and Real-time quantitative polymerase chain reaction were employed to quantify protein and messenger RNA expression. Using wound-healing and tube formation tests, the migratory proficiency and angiogenesis of HRMECs were evaluated.

RESULTS

NaB demonstrated a reduction in ROS production, as well as the release of LDH and MDA in HG-induced HRMECs. Additionally, NaB led to a decrease in protein expression of phosphorylation of NF-κB, NLRP3, Caspase 1, interleukin, vascular cell adhesion molecule-1 and intercellular adhesion molecule-1. The impact of HG on zonula occluden-1, a tight junction protein, was attenuated by NaB. Furthermore, NaB inhibited the migration and tube formation of HRMECs partly by ROS/NF-κB/NLRP3 pathway.

CONCLUSION

NaB suppresses the activation of ROS/NF-κB/NLRP3 signaling pathway and angiogenesis in HRMECs induced by HG.

Using gut microbiome metagenomic hypervariable features for diabetes screening and typing through supervised machine learning

Diabetes mellitus is a complex metabolic disorder and one of the fastest-growing global public health concerns. The gut microbiota is implicated in the pathophysiology of various diseases, including diabetes. This study utilized 16S rRNA metagenomic data from a volunteer citizen science initiative to investigate microbial markers associated with diabetes status (positive or negative) and type (type 1 or type 2 diabetes mellitus) using supervised machine learning (ML) models. The diversity of the microbiome varied according to diabetes status and type. Differential microbial signatures between diabetes types and negative group revealed an increased presence of Brucellaceae, Ruminococcaceae, Clostridiaceae, Micrococcaceae, Barnesiellaceae and Fusobacteriaceae in subjects with diabetes type 1, and Veillonellaceae, Streptococcaceae and the order Gammaproteobacteria in subjects with diabetes type 2. The decision tree, elastic net, random forest (RF) and support vector machine with radial kernel ML algorithms were trained to screen and type diabetes based on microbial profiles of 76 subjects with type 1 diabetes, 366 subjects with type 2 diabetes and 250 subjects without diabetes. Using the 1000 most variable features, tree-based models were the highest-performing algorithms. The RF screening models achieved the best performance, with an average area under the receiver operating characteristic curve (AUC) of 0.76, although all models lacked sensitivity. Reducing the dataset to 500 features produced an AUC of 0.77 with sensitivity increasing by 74% from 0.46 to 0.80. Model performance improved for the classification of negative-status and type 2 diabetes. Diabetes type models performed best with 500 features, but the metric performed poorly across all model iterations. ML has the potential to facilitate early diagnosis of diabetes based on microbial profiles of the gut microbiome.

Microvascular endothelial dysfunction in vascular senescence and disease

Cardiovascular disease (CVD) is the main cause of morbidity and mortality in the adult and the elderly, with increasing prevalence worldwide. A growing body of research has focused on the earliest stage of vascular decline-endothelial dysfunction (ED)-which at the microvascular level can anticipate in decades the diagnosis of CVD. This review aims to provide a prospect of the literature regarding the development of ED as an indissociable feature of the aging of the cardiovascular system, highlighting the role of inflammation in the process. Vascular aging consists of a lifelong continuum, which starts with cell respiration and its inherent production of reactive oxygen species. Molecular imbalance is followed by cellular epigenetic changes, which modulate immune cells, such as macrophage and lymphocyte subtypes. These mechanisms are influenced by lifestyle habits, which affect inflammation hotspots in organism, such as visceral fat and gut microbiota. The process can ultimately lead to an environment committed to the loss of the physiological functions of endothelial cells. In addition, we discuss lifestyle changes targeting the connection between age-related inflammation and vascular dysfunction. Addressing microvascular ED represents a critical endeavor in order to prevent or delay vascular aging and associated diseases.

EPA and DHA inhibit LDL-induced upregulation of human adipose tissue NLRP3 inflammasome/IL-1β pathway and its association with diabetes risk factors

Elevated numbers of atherogenic lipoproteins (apoB) predict the incidence of type 2 diabetes (T2D). We reported that this may be mediated via the activation of the NLRP3 inflammasome, as low-density lipoproteins (LDL) induce interleukin-1 beta (IL-1β) secretion from human white adipose tissue (WAT) and macrophages. However, mitigating nutritional approaches remained unknown. We tested whether omega-3 eicosapentaenoic and docosahexaenoic acids (EPA and DHA) treat LDL-induced upregulation of WAT IL-1β-secretion and its relation to T2D risk factors. Twelve-week intervention with EPA and DHA (2.7 g/day, Webber Naturals) abolished baseline group-differences in WAT IL-1β-secretion between subjects with high-apoB (N = 17) and low-apoB (N = 16) separated around median plasma apoB. Post-intervention LDL failed to trigger IL-1β-secretion and inhibited it in lipopolysaccharide-stimulated WAT. Omega-3 supplementation also improved β-cell function and postprandial fat metabolism in association with higher blood EPA and mostly DHA. It also blunted the association of WAT NLRP3 and IL1B expression and IL-1β-secretion with multiple cardiometabolic risk factors including adiposity. Ex vivo, EPA and DHA inhibited WAT IL-1β-secretion in a dose-dependent manner. In conclusion, EPA and DHA treat LDL-induced upregulation of WAT NLRP3 inflammasome/IL-1β pathway and related T2D risk factors. This may aid in the prevention of T2D and related morbidities in subjects with high-apoB.Clinical Trail Registration ClinicalTrials.gov (NCT04496154): Omega-3 to Reduce Diabetes Risk in Subjects with High Number of Particles That Carry "Bad Cholesterol" in the Blood - Full Text View - ClinicalTrials.gov.

Safety and Efficacy of Canakinumab for the Prevention and Control of Type 2 Diabetes Mellitus and Its Complications: A Systematic Review

Today, diabetes mellitus (DM) is one of the leading causes of morbidity and mortality globally.In this grim context, while our current armamentarium of anti-diabetic agents is vast and increasingly available, glycemic control in a significant proportion of these patients continues to remain sub-optimal.This necessitates the exploration of other potential cellular pathways and targets to effectively manage this notorious disease and its numerous complications. Inflammatory responses are thought to be implicated in the decline of pancreatic beta-cell function, with interleukin-1 beta (IL-1β) playing an important role in these pathways. Canakinumab, a human monoclonal anti-IL-1β antibody, operates by reducing inflammation, potentially safeguarding or enhancing pancreatic beta-cell function. This systematic review aims to study the safety and efficacy of canakinumab in the prevention and control of type 2 diabetes mellitus (T2DM) and its complications. This study was conducted in accordance with the PRISMA 2020 Guidelines. PubMed including MEDLINE, Google Scholar and Cochrane Library were used as information sources and randomized clinical trials and retrospective observational studies evaluating patients with T2DM or impaired glucose tolerance with/without complications receiving canakinumab, compared with placebo or standard therapy and reporting about glycemic indicators including hemoglobin A1C (HbA1C) or blood sugar levels (BSL) or insulin levels and/or inflammatory indicators including high-sensitivity C-reactive protein (hsCRP) or interleukin-6 (IL-6) were included. Non-randomized clinical trials, animal studies, review articles, case reports, case series, studies not in the English language and those evaluating type 1 DM were excluded. In total, 271 studies were identified to be included in this study. Subsequently, 27 were found to be duplicate records and were eliminated. Manual screening of title/abstract of 244 records was done which found 207 to be ineligible and 37 studies were shortlisted. These were retrieved and full-text screening was undertaken which resulted in the exclusion of 28 reports due to the following reasons: ineligible study design (17), studies evaluating type 1 DM (three), studies evaluating anakinra (one), trial being canceled (three) and duplicate studies (four). Subsequently, a total of nine studies were included in the final review. All studies were included post quality appraisal. We found that canakinumab had a modest but mostly non-significant effect on glycemic parameters including HbA1C, while having a consistently significant reduction in systemic inflammatory parameters like hsCRP and IL-6. Additionally, it was found to have a significant reduction in incident major adverse cardiovascular events (MACE). Canakinumab was also found to be safe and well-tolerated in all patient populations. Although canakinumab did not reduce incident T2DM, an exploration of alternative pathways and targets implicated in the pathogenesis of this disease process is warranted for the prevention and control of T2DM.

Interrelation of adipose tissue macrophages and fibrosis in obesity

Obesity is characterized by adipose tissue expansion, extracellular matrix remodelling and unresolved inflammation that contribute to insulin resistance and fibrosis. Adipose tissue macrophages represent the most abundant class of immune cells in adipose tissue inflammation and could be key mediators of adipocyte dysfunction and fibrosis in obesity. Although macrophage activation states are classically defined by the M1/M2 polarization nomenclature, novel studies have revealed a more complex range of macrophage phenotypes in response to external condition or the surrounding microenvironment. Here, we discuss the plasticity of adipose tissue macrophages (ATMs) in response to their microenvironment in obesity, with special focus on macrophage infiltration and polarization, and their contribution to adipose tissue fibrosis. A better understanding of the role of ATMs as regulators of adipose tissue remodelling may provide novel therapeutic strategies against obesity and associated metabolic diseases.

Therapeutic strategies targeting mechanisms of macrophages in diabetic heart disease

Diabetic heart disease (DHD) is a serious complication in patients with diabetes. Despite numerous studies on the pathogenic mechanisms and therapeutic targets of DHD, effective means of prevention and treatment are still lacking. The pathogenic mechanisms of DHD include cardiac inflammation, insulin resistance, myocardial fibrosis, and oxidative stress. Macrophages, the primary cells of the human innate immune system, contribute significantly to these pathological processes, playing an important role in human disease and health. Therefore, drugs targeting macrophages hold great promise for the treatment of DHD. In this review, we examine how macrophages contribute to the development of DHD and which drugs could potentially be used to target macrophages in the treatment of DHD.

Diabetes Mellitus to Accelerated Atherosclerosis: Shared Cellular and Molecular Mechanisms in Glucose and Lipid Metabolism

Diabetes is one of the critical independent risk factors for the progression of cardiovascular disease, and the underlying mechanism regarding this association remains poorly understood. Hence, it is urgent to decipher the fundamental pathophysiology and consequently provide new insights into the identification of innovative therapeutic targets for diabetic atherosclerosis. It is now appreciated that different cell types are heavily involved in the progress of diabetic atherosclerosis, including endothelial cells, macrophages, vascular smooth muscle cells, dependence on altered metabolic pathways, intracellular lipids, and high glucose. Additionally, extensive studies have elucidated that diabetes accelerates the odds of atherosclerosis with the explanation that these two chronic disorders share some common mechanisms, such as endothelial dysfunction and inflammation. In this review, we initially summarize the current research and proposed mechanisms and then highlight the role of these three cell types in diabetes-accelerated atherosclerosis and finally establish the mechanism pinpointing the relationship between diabetes and atherosclerosis.

Reappraisal of Adipose Tissue Inflammation in Obesity

Chronic low-grade inflammation is a central component in the pathogenesis of obesity-related expansion of adipose tissue and complications in other metabolic tissues. Five different signaling pathways are defined as dominant determinants of adipose tissue inflammation: These are increased circulating endotoxin due to dysregulation in the microbiota-gut-brain axis, systemic oxidative stress, macrophage accumulation, and adipocyte death. Finally, the nucleotide-binding and oligomerization domain (NOD) leucine-rich repeat family pyrin domain-containing 3 (NLRP3) inflammasome pathway is noted to be a key regulator of metabolic inflammation. The NLRP3 inflammasome and associated metabolic inflammation play an important role in the relationships among fatty acids and obesity. Several highly active molecules, including primarily leptin, resistin, adiponectin, visfatin, and classical cytokines, are abundantly released from adipocytes. The most important cytokines that are released by inflammatory cells infiltrating obese adipose tissue are tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1) (CCL-2), and IL-1. All these molecules mentioned above act on immune cells, causing local and then general inflammation. Three metabolic pathways are noteworthy in the development of adipose tissue inflammation: toll-like receptor 4 (TLR4)/phosphatidylinositol-3'-kinase (PI3K)/Protein kinase B (Akt) signaling pathway, endoplasmic reticulum (ER) stress-derived unfolded protein response (UPR), and inhibitor of nuclear factor kappa-B kinase beta (IKKβ)-nuclear factor kappa B (NF-κB) pathway. In fact, adipose tissue inflammation is an adaptive response that contributes to a visceral depot barrier that effectively filters gut-derived endotoxin. Excessive fatty acid release worsens adipose tissue inflammation and contributes to insulin resistance. However, suppression of adipose inflammation in obesity with anti-inflammatory drugs is not a rational solution and paradoxically promotes insulin resistance, despite beneficial effects on weight gain. Inflammatory pathways in adipocytes are indeed indispensable for maintaining systemic insulin sensitivity. Cannabinoid type 1 receptor (CB1R) is important in obesity-induced pro-inflammatory response; however, blockade of CB1R, contrary to anti-inflammatory drugs, breaks the links between insulin resistance and adipose tissue inflammation. Obesity, however, could be decreased by improving leptin signaling, white adipose tissue browning, gut microbiota interactions, and alleviating inflammation. Furthermore, capsaicin synthesized by chilies is thought to be a new and promising therapeutic option in obesity, as it prevents metabolic endotoxemia and systemic chronic low-grade inflammation caused by high-fat diet.

Native low-density lipoproteins are priming signals of the NLRP3 inflammasome/interleukin-1β pathway in human adipose tissue and macrophages

Elevated plasma numbers of atherogenic apoB-lipoproteins (apoB), mostly as low-density lipoproteins (LDL), predict diabetes risk by unclear mechanisms. Upregulation of the NLRP3 inflammasome/interleukin-1 beta (IL-1β) system in white adipose tissue (WAT) is implicated in type 2 diabetes (T2D); however, metabolic signals that stimulate it remain unexplored. We hypothesized that (1) subjects with high-apoB have higher WAT IL-1β-secretion than subjects with low-apoB, (2) WAT IL-1β-secretion is associated with T2D risk factors, and (3) LDL prime and/or activate the WAT NLRP3 inflammasome. Forty non-diabetic subjects were assessed for T2D risk factors related to systemic and WAT glucose and fat metabolism. Regulation of the NLRP3 inflammasome was explored using LDL without/with the inflammasome's priming and activation controls (LPS and ATP). LDL induced IL1B-expression and IL-1β-secretion in the presence of ATP in WAT and macrophages. Subjects with high-apoB had higher WAT IL-1β-secretion independently of covariates. The direction of association of LDL-induced WAT IL-1β-secretion to T2D risk factors was consistently pathological in high-apoB subjects only. Adjustment for IL-1β-secretion eliminated the association of plasma apoB with T2D risk factors. In conclusion, subjects with high-apoB have higher WAT IL-1β-secretion that may explain their risk for T2D and may be related to LDL-induced priming of the NLRP3 inflammasome.ClinicalTrials.gov (NCT04496154): Omega-3 to Reduce Diabetes Risk in Subjects With High Number of Particles That Carry "Bad Cholesterol" in the Blood-Full Text View-ClinicalTrials.gov.

A novel dual NLRP1 and NLRP3 inflammasome inhibitor for the treatment of inflammatory diseases

Objectives

Inflammasomes induce maturation of the inflammatory cytokines IL-1β and IL-18, whose activity is associated with the pathophysiology of a wide range of infectious and inflammatory diseases. As validated therapeutic targets for the treatment of acute and chronic inflammatory diseases, there has been intense interest in developing small-molecule inhibitors to target inflammasome activity and reduce disease-associated inflammatory burden.

Methods

We examined the therapeutic potential of a novel small-molecule inhibitor, and associated derivatives, termed ADS032 to target and reduce inflammasome-mediated inflammation in vivo. In vitro, we characterised ADS032 function, target engagement and specificity.

Results

We describe ADS032 as the first dual NLRP1 and NLRP3 inhibitor. ADS032 is a rapid, reversible and stable inflammasome inhibitor that directly binds both NLRP1 and NLRP3, reducing secretion and maturation of IL-1β in human-derived macrophages and bronchial epithelial cells in response to the activation of NLPR1 and NLRP3. ADS032 also reduced NLRP3-induced ASC speck formation, indicative of targeting inflammasome formation. In vivo, ADS032 reduced IL-1β and TNF-α levels in the serum of mice challenged i.p. with LPS and reduced pulmonary inflammation in an acute model of lung silicosis. Critically, ADS032 protected mice from lethal influenza A virus challenge, displayed increased survival and reduced pulmonary inflammation.

Conclusion

ADS032 is the first described dual inflammasome inhibitor and a potential therapeutic to treat both NLRP1- and NLRP3-associated inflammatory diseases and also constitutes a novel tool that allows examination of the role of NLRP1 in human disease.

Anti-HIV Drugs Reduce Risk of Prediabetes and Progression to Type 2 Diabetes in HIV-Infected Patients

The aim of this study was to investigate whether the use of nucleoside reverse transcriptase inhibitors (NRTIs) impacts the incidence of prediabetes or type 2 diabetes mellitus (T2DM) or the progression from prediabetes to T2DM in people living with HIV (PLWH). We conducted a retrospective cohort study using the U.S. Veterans Health Administration database among adult patients with an HIV diagnosis from the year 2000 until 2021 to determine the incidence of prediabetes and further progression to T2DM among NRTI exposed and unexposed patients. A multistate model was used to evaluate progression from normoglycemia to prediabetes and then to T2DM, and covariate adjustment with the Cox proportional hazards model was used to estimate the hazard ratios. Among 32,240 veterans diagnosed with HIV, prediabetes and T2DM were observed among 20.2% and 20.7% of patients, respectively. Among those diagnosed with prediabetes, 31.8% progressed to T2DM. Patients exposed to NRTIs at any time (86.6%), had a reduced risk of prediabetes [HR 0.50 (0.47-0.53 95% CI)] and among prediabetics, a lower risk of progression to T2DM [HR 0.73 (0.63-0.85 95% CI)] when compared to patients who never used NRTIs. In summary, NRTIs may reduce the risk of developing prediabetes and the progression from prediabetes to T2DM in PLWH.

Gut Microbiota and Time-Restricted Feeding/Eating: A Targeted Biomarker and Approach in Precision Nutrition

Each individual has a unique gut microbiota; therefore, the genes in our microbiome outnumber the genes in our genome by about 150 to 1. Perturbation in host nutritional status influences gut microbiome composition and vice versa. The gut microbiome can help in producing vitamins, hormones, and other active metabolites that support the immune system; harvest energy from food; aid in digestion; protect against pathogens; improve gut transit and function; send signals to the brain and other organs; oscillate the circadian rhythm; and coordinate with the host metabolism through multiple cellular pathways. Gut microbiota can be influenced by host genetics, medications, diet, and lifestyle factors from preterm to aging. Aligning with precision nutrition, identifying a personalized microbiome mandates the provision of the right nutrients at the right time to the right patient. Thus, before prescribing a personalized treatment, it is crucial to monitor and count the gut flora as a focused biomarker. Many nutritional approaches that have been developed help in maintaining and restoring an optimal microbiome such as specific diet therapy, nutrition interventions, and customized eating patterns. One of these approaches is time-restricted feeding/eating (TRF/E), a type of intermittent fasting (IF) in which a subject abstains from food intake for a specific time window. Such a dietary modification might alter and restore the gut microbiome for proper alignment of cellular and molecular pathways throughout the lifespan. In this review, we have highlighted that the gut microbiota would be a targeted biomarker and TRF/E would be a targeted approach for restoring the gut-microbiome-associated molecular pathways such as hormonal signaling, the circadian system, metabolic regulators, neural responses, and immune-inflammatory pathways. Consequently, modulation of the gut microbiota through TRF/E could contribute to proper utilization and availability of the nutrients and in this way confer protection against diseases for harnessing personalized nutrition approaches to improve human health.

Impact of semaglutide on high-sensitivity C-reactive protein: exploratory patient-level analyses of SUSTAIN and PIONEER randomized clinical trials

Background

Exploratory analysis to determine the effect of semaglutide versus comparators on high-sensitivity C-reactive protein (hsCRP) in subjects with type 2 diabetes.

Methods

Trials of once-weekly subcutaneous (SUSTAIN 3) and once-daily oral (PIONEER 1, 2, 5) semaglutide with hsCRP data were analyzed. Subjects with type 2 diabetes (N = 2482) received semaglutide (n = 1328) or comparators (placebo, n = 339; exenatide extended-release, n = 405; empagliflozin, n = 410). hsCRP ratio to baseline at end-of-treatment was analyzed overall, by clinical cutoff (< 1.0, ≥ 1.0 to ≤ 3.0, or > 3.0 mg/L), by tertile, and by estimated glomerular filtration rate in PIONEER 5 (a trial which was conducted in a population with type 2 diabetes and chronic kidney disease [CKD]). Mediation analyses assessed the effect of change in glycated hemoglobin (HbA_1c) and/or change in body weight (BW) on hsCRP reductions.

Results

Geometric mean baseline hsCRP was similar across trials (range 2.7–3.0 mg/L). Semaglutide reduced hsCRP levels by clinical cutoffs and tertiles from baseline to end-of-treatment in all trials versus comparators (estimated treatment ratios [ETRs] versus comparators: 0.70–0.76; p < 0.01) except versus placebo in PIONEER 5 (ETR [95% CI]: 0.83 [0.67–1.03]; p > 0.05). The effect of semaglutide on hsCRP was partially mediated (20.6–61.8%) by change in HbA_1c and BW.

Conclusions

Semaglutide reduced hsCRP ratios-to-baseline versus comparators in subjects with type 2 diabetes (not significant with CKD). This effect was partially mediated via reductions in HbA_1c and BW and potentially by a direct effect of semaglutide. Semaglutide appears to have an anti-inflammatory effect, which is being further investigated in ongoing trials.

Trial registrations: ClinicalTrials.gov identifiers: NCT01885208 (first registered June 2013), NCT02906930 (first registered September 2016), NCT02863328 (first registered August 2016), NCT02827708 (first registered July 2016).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01585-7.

Loss of Lipocalin 10 Exacerbates Diabetes-Induced Cardiomyopathy via Disruption of Nr4a1-Mediated Anti-Inflammatory Response in Macrophages

Metabolic disorders (i.e., hyperglycemia, hyperlipidemia, and hyperinsulinemia) cause increased secretion of inflammatory cytokines/chemokines, leading to gradual loss of cardiac resident macrophage population and increased accumulation of inflammatory monocytes/macrophages in the heart. Such self-perpetuating effect may contribute to the development of cardiomyopathy during diabetes. Recent meta-analysis data reveal that lipocalin 10 (Lcn10) is significantly downregulated in cardiac tissue of patients with heart failure but is increased in the blood of septic patients. However, the functional role of Lcn10 in cardiac inflammation triggered by metabolic disorders has never been investigated. In this study, we demonstrate that the expression of Lcn10 in macrophages was significantly decreased under multiple metabolic stress conditions. Furthermore, Lcn10-null macrophages exhibited pro-inflammatory phenotype in response to inflammation stimuli. Next, using a global Lcn10-knockout (KO) mouse model to induce type-2 diabetes (T2D), we observed that loss of Lcn10 promoted more pro-inflammatory macrophage infiltration into the heart, compared to controls, leading to aggravated insulin resistance and impaired cardiac function. Similarly, adoptive transfer of Lcn10-KO bone marrow cells into X-ray irradiated mice displayed higher ratio of pro-/anti-inflammatory macrophages in the heart and worsened cardiac function than those mice received wild-type (WT) bone marrows upon T2D conditions. Mechanistically, RNA-sequencing analysis showed that Nr4a1, a nuclear receptor known to have potent anti-inflammatory effects, is involved in Lcn10-mediated macrophage activation. Indeed, we found that nuclear translocation of Nr4a1 was disrupted in Lcn10-KO macrophages upon stimulation with LPS + IFNγ. Accordingly, treatment with Cytosporone B (CsnB), an agonist of Nr4a1, attenuated the pro-inflammatory response in Lcn10-null macrophages and partially improved cardiac function in Lcn10-KO diabetic mice. Together, these findings indicate that loss of Lcn10 skews macrophage polarization to pro-inflammatory phenotype and aggravates cardiac dysfunction during type-2 diabetes through the disruption of Nr4a1-mediated anti-inflammatory signaling pathway in macrophages. Therefore, reduction of Lcn10 expression observed in diabetic macrophages may be responsible for the pathogenesis of diabetes-induced cardiac dysfunction. It suggests that Lcn10 might be a potential therapeutic factor for diabetic heart failure.

Oxymatrine inhibits the pyroptosis in rat insulinoma cells by affecting nuclear factor kappa B and nuclear factor (erythroid-derived 2)-like 2 protein/heme oxygenase-1 pathways

As the mechanism underlying glucose metabolism regulation by oxymatrine is unclear, this study investigated the effects of oxymatrine on pyroptosis in INS-1 cells. Flow cytometry was employed to examine cell pyroptosis and reactive oxygen species (ROS) production. Cell pyroptosis was also investigated via transmission electron microscopy and lactate dehydrogenase (LDH) release. Protein levels were detected using western blotting and interleukin (IL)-1β and IL-18 secretion by enzyme-linked immunosorbent assay. The caspase-1 activity and DNA-binding activity of nuclear factor kappa B (NF-κB) and nuclear factor (erythroid-derived 2)-like 2 protein (Nrf2) were also assessed. In the high glucose and high fat-treated INS-1 cells (HG + PA), the caspase-1 activity and LDH content, as well as Nod-like receptor family pyrin domain containing 3, Gsdmd-N, caspase-1, apoptosis-associated speck-like protein containing a CARD, IL-1β, and IL-18 levels were increased. Moreover, P65 protein levels increased in the nucleus but decreased in the cytoplasm. Oxymatrine attenuated these effects and suppressed high glucose and high fat-induced ROS production. The increased levels of nuclear Nrf2 and heme oxygenase-1 (HO-1) in the HG + PA cells were further elevated after oxymatrine treatment, whereas cytoplasmic Nrf2 and Keleh-like ECH-associated protein levels decreased. Additionally, the elevated transcriptional activity of p65 in HG + PA cells was reduced by oxymatrine, whereas that of Nrf2 increased. The results indicate that the inhibition of pyroptosis in INS-1 cells by oxymatrine, a key factor in its glucose metabolism regulation, involves the suppression of the NF-κB pathway and activation of the Nrf2/HO-1 pathway.

Picroside II alleviates DSS-induced ulcerative colitis by suppressing the production of NLRP3 inflammasomes through NF-κB signaling pathway

CONTEXT

Ulcerative colitis (UC) is a common acute or chronic intestinal disease with the imbalance of inflammation. Picroside II (P-II) exerts the protective role in various inflammation-related diseases. However, the effect of P-II on UC is still unclear.

OBJECTIVE

To explore the effect of P-II on UC and its potential mechanism.

MATERIALS AND METHODS

Human monocytic leukemia cell line THP-1 were treated with phorbol ester (PMA) to differentiate into macrophage. The differentiated THP-1 cells were hatched with LPS combined with ATP or Nigericin to activate the NLRP3 inflammasome in vitro. The UC model was constructed by injection of DSS into mice.

RESULTS

The maximum non-toxic concentration of P-II on THP-1 cells was 60 μM. LPS combined with ATP or Nigericin stimulated the production of IL-1β, which was antagonized by P-II treatment. Meanwhile, P-II administration interfered the aggregation of ASC and the assembly of NLRP3 inflammasomes. Also, P-II treatment reduced the LPS and ATP-induced elevation of the relative protein expression of NLRP3, pro-caspase-1, IL-1β and p-p65/p65, and the concentration of TNF-α and IL-6. Besides, the NF-κB specific inhibitor BAY-117082 notably repressed the LPS together with ATP-enhanced the relative protein expression of NLRP3, caspase-1 and IL-1β. Moreover, in vivo results showed that P-II relieved the DDS-induced UC, as evidenced by the improvement of mice weight, DAI and pathological scores. In addition, P-II treatment notably decreased DDS-promoted expression of NLRP3 inflammasomes and inflammatory factors in vivo.

CONCLUSION

P-II alleviated DSS-induced UC by repressing the production of NLRP3 inflammasomes via NF-κB signaling pathway.

The Influence of Different Types of Diabetes on Vascular Complications

The final outcome of diabetes is chronic complications, of which vascular complications are the most serious, which is the main cause of death for diabetic patients and the direct cause of the increase in the cost of diabetes. Type 1 and type 2 diabetes are the main types of diabetes, and their pathogenesis is completely different. Type 1 diabetes is caused by genetics and immunity to destroy a large number of β cells, and insulin secretion is absolutely insufficient, which is more prone to microvascular complications. Type 2 diabetes is dominated by insulin resistance, leading to atherosclerosis, which is more likely to progress to macrovascular complications. This article explores the pathogenesis of two types of diabetes, analyzes the pathogenesis of different vascular complications, and tries to explain the different trends in the progression of different types of diabetes to vascular complications, in order to better prevent diabetes and its vascular complications.

The Homeostasis of Cartilage Matrix Remodeling and the Regulation of Volume-Sensitive Ion Channel

Degenerative joint diseases of the hips and knees are common and are accompanied by severe pain and movement disorders. At the microscopic level, the main characteristics of osteoarthritis are the continuous destruction and degeneration of cartilage, increased cartilage extracellular matrix catabolism, decreased anabolism, increased synovial fluid, and decreased osmotic pressure. Cell volume stability is mainly regulated by ion channels, many of which are expressed in chondrocytes. These ion channels are closely related to pain regulation, volume regulation, the inflammatory response, cell proliferation, apoptosis, and cell differentiation. In this review, we focus on the important role of volume control-related ion channels in cartilage matrix remodeling and summarize current views. In addition, the potential mechanism of the volume-sensitive anion channel LRRC8A in the early occurrence of osteoarthritis is discussed.

Intestinal alkaline phosphatase deficiency increases the risk of diabetes

INTRODUCTION

Our previous case-control study demonstrated that a high level of intestinal alkaline phosphatase (IAP), an endotoxin-detoxifying anti-inflammatory enzyme secreted by villus-associated enterocytes and excreted with stool, plays a protective role against type 2 diabetes mellitus (T2DM) irrespective of obesity. In the current study, we investigated the long-term effect of IAP deficiency (IAPD) on the pathogenesis of T2DM.

RESEARCH DESIGN AND METHODS

A healthy cohort of participants without diabetes (30-60 years old), comprising 188 without IAPD (IAP level: ≥65 U/g stool) and 386 with IAPD (IAP level: <65 U/g stool), were followed up for 5 years. We measured stool IAP (STAP) and fasting plasma glucose, and calculated the risk ratio (RR) using log-binomial regression model.

RESULTS

T2DM incidence rates were 8.0%, 11.7%, 25.6%, and 33.3% in participants with 'persistent no IAPD' (IAP level: always ≥65 U/g stool), 'remittent IAPD' (IAP level: increased from <65 U/g stool to ≥65 U/g stool), 'persistent IAPD' (IAP level: always <65 U/g stool), and 'incident IAPD' (IAP level: decreased from ≥65 U/g stool to <65 U/g stool), respectively. Compared with 'persistent no IAPD' the risk of developing T2DM with 'incident IAPD' was 270% higher (RR: 3.69 (95% CI 1.76 to 7.71), χ² p<0.001). With 'persistent IAPD' the risk was 230% higher (RR: 3.27 (95% CI 1.64 to 6.50), p<0.001). 'Remittent IAPD' showed insignificant risk (RR: 2.24 (95% CI 0.99 to 5.11), p=0.0541). Sensitivity analyses of persistent IAP levels revealed that, compared with participants of the highest persistent IAP pentile (always >115 U/g stool), the rate of increase of fasting glycemia was double and the risk of developing T2DM was 1280% higher (RR: 13.80 (95% CI 1.87 to 101.3), p=0.0099) in participants of the lowest persistent IAP pentile (always <15 U/g stool). A diabetes pathogenesis model is presented.

CONCLUSIONS

IAPD increases the risk of developing T2DM, and regular STAP tests would predict individual vulnerability to T2DM. Oral IAP supplementation might prevent T2DM.

The cGAS-STING pathway: more than fighting against viruses and cancer

In the classic Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) synthase (cGAS)-stimulator of interferon genes (STING) pathway, downstream signals can control the production of type I interferon and nuclear factor kappa-light-chain-enhancer of activated B cells to promote the activation of pro-inflammatory molecules, which are mainly induced during antiviral responses. However, with progress in this area of research, studies focused on autoimmune diseases and chronic inflammatory conditions that may be relevant to cGAS-STING pathways have been conducted. This review mainly highlights the functions of the cGAS-STING pathway in chronic inflammatory diseases. Importantly, the cGAS-STING pathway has a major impact on lipid metabolism. Different research groups have confirmed that the cGAS-STING pathway plays an important role in the chronic inflammatory status in various organs. However, this pathway has not been studied in depth in diabetes and diabetes-related complications. Current research on the cGAS-STING pathway has shown that the targeted therapy of diseases that may be caused by inflammation via the cGAS-STING pathway has promising outcomes.

Pneumonia hospitalizations and the subsequent risk of incident ischaemic cardiovascular disease in Chinese adults

BACKGROUND

Acute respiratory infections have been associated with a transient increase in cardiovascular risk. However, whether such an association persists beyond 1 month and the potential modifying effect of cardiovascular risk factors on such an association are less well established.

METHODS

The China Kadoorie Biobank enrolled 512 726 participants aged 30-79 years from 10 areas across China during 2004-2008. By the end of 2017, a total of 5444 participants with new-onset ischaemic heart disease (IHD) and 4846 with ischaemic stroke (IS) who also had at least a record of hospitalization for pneumonia during follow-up were included. We used a self-controlled case-series method and calculated the age- and season-adjusted relative incidences (RIs) and 95% confidence intervals (CIs) for ischaemic cardiovascular disease (CVD) after pneumonia.

RESULTS

The risk of ischaemic CVD increased during days 1-3 after pneumonia hospitalization, with an RI (95% CI) of 4.24 (2.92-6.15) for IHD and 1.85 (1.02-3.35) for IS. The risk gradually reduced with longer duration since pneumonia hospitalization but remained elevated until days 92-365 for IHD (1.23, 1.12-1.35) and days 29-91 for IS (1.25, 1.05-1.48). Pre-existing cardiovascular risk factors amplified the associations between pneumonia and ischaemic CVD risks, such as chronic obstructive pulmonary disease for both IHD and IS, and diabetes and smoking for IHD (all Pinteraction < 0.05). Besides, the risk of ischaemic CVD was also higher among the participants aged ≥70 years (Pinteraction < 0.001 for IHD and 0.033 for IS).

CONCLUSION

Among middle-aged and older Chinese adults, pneumonia hospitalization was associated with both short- and long-term increases in ischaemic CVD risk for ≤1 year.

Identification of fluoxetine as a direct NLRP3 inhibitor to treat atrophic macular degeneration

The atrophic form of age-related macular degeneration (dry AMD) affects nearly 200 million people worldwide. There is no Food and Drug Administration (FDA)-approved therapy for this disease, which is the leading cause of irreversible blindness among people over 50 y of age. Vision loss in dry AMD results from degeneration of the retinal pigmented epithelium (RPE). RPE cell death is driven in part by accumulation of Alu RNAs, which are noncoding transcripts of a human retrotransposon. Alu RNA induces RPE degeneration by activating the NLRP3-ASC inflammasome. We report that fluoxetine, an FDA-approved drug for treating clinical depression, binds NLRP3 in silico, in vitro, and in vivo and inhibits activation of the NLRP3-ASC inflammasome and inflammatory cytokine release in RPE cells and macrophages, two critical cell types in dry AMD. We also demonstrate that fluoxetine, unlike several other antidepressant drugs, reduces Alu RNA-induced RPE degeneration in mice. Finally, by analyzing two health insurance databases comprising more than 100 million Americans, we report a reduced hazard of developing dry AMD among patients with depression who were treated with fluoxetine. Collectively, these studies identify fluoxetine as a potential drug-repurposing candidate for dry AMD.

Tetrahydrocurcumin Ameliorates Kidney Injury and High Systolic Blood Pressure in High-Fat Diet-Induced Type 2 Diabetic Mice

BACKGROUND

Activation of the intrarenal renin-angiotensin system (RAS) is implicated in the pathogenesis of kidney injury and hypertension. We aimed to investigate the protective effect of tetrahydrocurcumin (THU) on intrarenal RAS expression, kidney injury, and systolic blood pressure (SBP) in high-fat diet (HFD)-induced type 2 diabetic mice.

METHODS

Eight-week-old male mice were fed a regular diet (RD) or HFD for 12 weeks, and THU (50 or 100 mg/kg/day) was intragastrically administered with HFD. Physiological and metabolic changes were monitored and the expression of RAS components and markers of kidney injury were assessed.

RESULTS

HFD-fed mice exhibited hyperglycemia, insulin resistance, and dyslipidemia compared to those in the RD group (P<0.05). Kidney injury in these mice was indicated by an increase in the ratio of albumin to creatinine, glomerular hypertrophy, and the effacement of podocyte foot processes. Expression of intrarenal angiotensin-converting enzyme, angiotensin II type I receptor, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-4, and monocyte chemoattractant protein-1 was also markedly increased in HFD-fed mice. HFD-fed mice exhibited elevated SBP that was accompanied by an increase in the wall thickness and vascular cross-sectional area (P<0.05), 12 weeks post-HFD consumption. Treatment with THU (100 mg/kg/day) suppressed intrarenal RAS activation, improved insulin sensitivity, and reduced SBP, thus, attenuating kidney injury in these mice.

CONCLUSION

THU alleviated kidney injury in mice with HFD-induced type 2 diabetes, possibly by blunting the activation of the intrarenal RAS/nicotinamide adenine dinucleotide phosphate oxidase IV (NOX4)/monocyte chemoattractant protein 1 (MCP-1) axis and by lowering the high SBP.

Inflammasomes as therapeutic targets in human diseases

Inflammasomes are protein complexes of the innate immune system that initiate inflammation in response to either exogenous pathogens or endogenous danger signals. Inflammasome multiprotein complexes are composed of three parts: a sensor protein, an adaptor, and pro-caspase-1. Activation of the inflammasome leads to the activation of caspase-1, which cleaves pro-inflammatory cytokines such as IL-1β and IL-18, leading to pyroptosis. Effectors of the inflammasome not only provide protection against infectious pathogens, but also mediate control over sterile insults. Aberrant inflammasome signaling has been implicated in the development of cardiovascular and metabolic diseases, cancer, and neurodegenerative disorders. Here, we review the role of the inflammasome as a double-edged sword in various diseases, and the outcomes can be either good or bad depending on the disease, as well as the genetic background. We highlight inflammasome memory and the two-shot activation process. We also propose the M- and N-type inflammation model, and discuss how the inflammasome pathway may be targeted for the development of novel therapy.

Protein arginine methyltransferase 1 contributes to the development of allergic rhinitis by promoting the production of epithelial-derived cytokines

BACKGROUND

Arginine methylation is a posttranslational modification mediated by protein arginine methyltransferases (PRMTs). Although previous studies have shown that PRMT1 contributes to the severity of allergic airway inflammation or asthma, the underlying mechanism is poorly understood.

OBJECTIVE

This study aimed to explore the role of PRMT1 and its relevant mechanism in the development of allergic rhinitis (AR).

METHODS

The expression levels of PRMTs and cytokines were determined by RT-PCR, and the localization of PRMT1 was determined by immunohistochemistry and confocal microscopy. The levels of house dust mite (HDM)-specific immunoglobulins in serum and of cytokines in nasal lavage fluids were determined by ELISA. PRMT1 inhibition was achieved by siRNA and treatment with the pan PRMT inhibitor arginine N-methyltransferase inhibitor-1.

RESULTS

PRMT1 expression was significantly increased in the nasal mucosa of patients and mice with AR. The degree of eosinophilic infiltration in the nasal mucosa was reduced in PRMT1+/- AR mice compared with wild-type mice. PRMT1 haploinsufficiency reduced the levels of HDM-specific immunoglobulins in serum and those of TH2 (IL-4, IL-5, and IL-13) and epithelial (thymic stromal lymphopoietin [TSLP], IL-25, and IL-33) cytokines in the nasal lavage fluids of AR mice. In nasal epithelial cells, HDM and IL-4 cooperate to enhance PRMT1 expression through a mitogen-activated protein kinase-dependent pathway. In addition, PRMT1 was essential for the production of TSLP, IL-25, and IL-33 in response to HDM and IL-4. Arginine N-methyltransferase inhibitor-1 treatment alleviated AR in the mouse model.

CONCLUSIONS

PRMT1 plays an important role in AR development by regulating epithelial-derived cytokine production and might be a new therapeutic target for AR.

Specific NLRP3 Inhibition Protects Against Diabetes-Associated Atherosclerosis

Low-grade persistent inflammation is a feature of diabetes-driven vascular complications, in particular activation of the Nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome to trigger the maturation and release of the inflammatory cytokine interleukin-1β (IL-1β). We investigated whether inhibiting the NLRP3 inflammasome, through the use of the specific small-molecule NLRP3 inhibitor MCC950, could reduce inflammation, improve vascular function, and protect against diabetes-associated atherosclerosis in the streptozotocin-induced diabetic apolipoprotein E-knockout mouse. Diabetes led to an approximately fourfold increase in atherosclerotic lesions throughout the aorta, which were significantly attenuated with MCC950 (P < 0.001). This reduction in lesions was associated with decreased monocyte-macrophage content, reduced necrotic core, attenuated inflammatory gene expression (IL-1β, tumor necrosis factor-α, intracellular adhesion molecule 1, and MCP-1; P < 0.05), and reduced oxidative stress, while maintaining fibrous cap thickness. Additionally, vascular function was improved in diabetic vessels of mice treated with MCC950 (P < 0.05). In a range of cell lines (murine bone marrow-derived macrophages, human monocytic THP-1 cells, phorbol 12-myristate 13-acetate-differentiated human macrophages, and aortic smooth muscle cells from humans with diabetes), MCC950 significantly reduced IL-1β and/or caspase-1 secretion and attenuated leukocyte-smooth muscle cell interactions under high glucose or lipopolysaccharide conditions. In summary, MCC950 reduces plaque development, promotes plaque stability, and improves vascular function, suggesting that targeting NLRP3-mediated inflammation is a novel therapeutic strategy to improve diabetes-associated vascular disease.

Therapeutic Potential of Tpl2 (Tumor Progression Locus 2) Inhibition on Diabetic Vasculopathy Through the Blockage of the Inflammasome Complex

OBJECTIVE

Diabetic retinopathy, one of retinal vasculopathy, is characterized by retinal inflammation, vascular leakage, blood-retinal barrier breakdown, and neovascularization. However, the molecular mechanisms that contribute to diabetic retinopathy progression remain unclear. Approach and Results: Tpl2 (tumor progression locus 2) is a protein kinase implicated in inflammation and pathological vascular angiogenesis. Nε-carboxymethyllysine (CML) and inflammatory cytokines levels in human sera and in several diabetic murine models were detected by ELISA, whereas liquid chromatography-tandem mass spectrometry analysis was used for whole eye tissues. The CML and p-Tpl2 expressions on the human retinal pigment epithelium (RPE) cells were determined by immunofluorescence. Intravitreal injection of pharmacological inhibitor or NA (neutralizing antibody) was used in a diabetic rat model. Retinal leukostasis, optical coherence tomography, and H&E staining were used to observe pathological features. Sera of diabetic retinopathy patients had significantly increased CML levels that positively correlated with diabetic retinopathy severity and foveal thickness. CML and p-Tpl2 expressions also significantly increased in the RPE of both T1DM and T2DM diabetes animal models. Mechanistic studies on RPE revealed that CML-induced Tpl2 activation and NADPH oxidase, and inflammasome complex activation were all effectively attenuated by Tpl2 inhibition. Tpl2 inhibition by NA also effectively reduced inflammatory/angiogenic factors, retinal leukostasis in streptozotocin-induced diabetic rats, and RPE secretion of inflammatory cytokines. The attenuated release of angiogenic factors led to inhibited vascular abnormalities in the diabetic animal model.

CONCLUSIONS

The inhibition of Tpl2 can block the inflammasome signaling pathway in RPE and has potential clinical and therapeutic implications in diabetes-associated retinal microvascular dysfunction.

An overview of disease models for NLRP3 inflammasome over-activation

Introduction: Inflammatory reactions, including those mediated by the NLRP3 inflammasome, maintain the body's homeostasis by removing pathogens, repairing damaged tissues, and adapting to stressed environments. However, uncontrolled activation of the NLRP3 inflammasome tends to cause various diseases using different mechanisms. Recently, many inhibitors of the NLRP3 inflammasome have been reported and many are being developed. In order to assess their efficacy, specificity, and mechanism of action, the screening process of inhibitors requires various types of cell and animal models of NLRP3-associated diseases.Areas covered: In the following review, the authors give an overview of the cell and animal models that have been used during the research and development of various inhibitors of the NLRP3 inflammasome.Expert opinion: There are many NLRP3 inflammasome inhibitors, but most of the inhibitors have poor specificity and often influence other inflammatory pathways. The potential risk for cross-reaction is high; therefore, the development of highly specific inhibitors is essential. The selection of appropriate cell and animal models, and combined use of different models for the evaluation of these inhibitors can help to clarify the target specificity and therapeutic effects, which is beneficial for the development and application of drugs targeting the NLRP3 inflammasome.

P2X7 receptor and the NLRP3 inflammasome: Partners in crime

Adenosine triphosphate (ATP) is a molecule that on one hand plays a central role in cellular energetics and which on the other is a ubiquitous signaling molecule when released into the extracellular media. Extracellular ATP accumulates in inflammatory environments where it acts as a damage-associated molecular pattern and activates the purinergic P2X receptor 7 (P2X7) in immune cells. P2X7 receptor activation induces the formation of the nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing 3 (NLRP3) inflammasome and the activation of the inflammatory caspase-1. Caspase-1 causes an inflammatory type of cell death called pyroptosis through the release of pro-inflammatory cytokines and intracellular content. Consequently, intense research efforts have been devoted to the design of novel anti-inflammatory therapies, focusing in particular on the P2X7 receptor and the NLRP3 pathway and the introduction of new blocking molecules in early phase clinical trials.

Loss of GRB2 associated binding protein 1 in arteriosclerosis obliterans promotes host autophagy

Background:

Arteriosclerosis obliterans (ASO) is a major cause of adult limb loss worldwide. Autophagy of vascular endothelial cell (VEC) contributes to the ASO progression. However, the molecular mechanism that controls VEC autophagy remains unclear. In this study, we aimed to explore the role of the GRB2 associated binding protein 1 (GAB1) in regulating VEC autophagy.

Methods:

In vivo and in vitro studies were applied to determine the loss of adapt protein GAB1 in association with ASO progression. Histological GAB1 expression was measured in sclerotic vascular intima and normal vascular intima. Gain- and loss-of-function of GAB1 were applied in VEC to determine the effect and potential downstream signaling of GAB1.

Results:

The autophagy repressor p62 was significantly downregulated in ASO intima as compared to that in healthy donor (0.80 vs. 0.20, t = 6.43, P < 0.05). The expression level of GAB1 mRNA (1.00 vs. 0.24, t = 7.41, P < 0.05) and protein (0.72 vs. 0.21, t = 5.97, P < 0.05) was significantly decreased in ASO group as compared with the control group. Loss of GAB1 led to a remarkable decrease in LC3II (1.19 vs. 0.68, t = 5.99, P < 0.05), whereas overexpression of GAB1 significantly led to a decrease in LC3II level (0.41 vs. 0.93, t = 7.12, P < 0.05). Phosphorylation levels of JNK and p38 were significantly associated with gain- and loss-of-function of GAB1 protein.

Conclusion:

Loss of GAB1 promotes VEC autophagy which is associated with ASO. GAB1 and its downstream signaling might be potential therapeutic targets for ASO treatment.

Tissue-level inflammation and ventricular remodeling in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a common cardiac condition caused primarily by sarcomeric protein mutations with several distinct phenotypes, ranging from asymmetric septal hypertrophy, either with or without left ventricular outflow tract obstruction, to moderate left ventricular dilation with or without apical aneurysm formation and marked, end-stage dilation with refractory heart failure. Sudden cardiac death can occur at any stage. The phenotypic variability observed in HCM is the end-result of many factors, including pre-load, after-load, wall stress and myocardial ischemia stemming from microvascular dysfunction and thrombosis; however, tissue level inflammation to include leukocyte-derived extracellular traps consisting of chromatin and histones, apoptosis, proliferation of matrix proteins and impaired or dysfunctional regulatory pathways contribute as well. Our current understanding of the pathobiology, developmental stages, transition from hypertrophy to dilation and natural history of HCM with emphasis on the role of tissue-level inflammation in myocardial fibrosis and ventricular remodeling is summarized.

Repurposing anti-inflammasome NRTIs for improving insulin sensitivity and reducing type 2 diabetes development

Innate immune signaling through the NLRP3 inflammasome is activated by multiple diabetes-related stressors, but whether targeting the inflammasome is beneficial for diabetes is still unclear. Nucleoside reverse-transcriptase inhibitors (NRTI), drugs approved to treat HIV-1 and hepatitis B infections, also block inflammasome activation. Here, we show, by analyzing five health insurance databases, that the adjusted risk of incident diabetes is 33% lower in patients with NRTI exposure among 128,861 patients with HIV-1 or hepatitis B (adjusted hazard ratio for NRTI exposure, 0.673; 95% confidence interval, 0.638 to 0.710; P < 0.0001; 95% prediction interval, 0.618 to 0.734). Meanwhile, an NRTI, lamivudine, improves insulin sensitivity and reduces inflammasome activation in diabetic and insulin resistance-induced human cells, as well as in mice fed with high-fat chow; mechanistically, inflammasome-activating short interspersed nuclear element (SINE) transcripts are elevated, whereas SINE-catabolizing DICER1 is reduced, in diabetic cells and mice. These data suggest the possibility of repurposing an approved class of drugs for prevention of diabetes.

Energy Provisioning and Inflammasome Activation: The Pivotal Role of AMPK in Sterile Inflammation and Associated Metabolic Disorders

BACKGROUND

Body defenses and metabolic processes probably co-evolved in such a way that rapid, energy-intensive acute inflammatory repair is functionally integrated with energy allocation in a starvation/ infection / injury-prone primitive environment. Disruptive metabolic surplus, aggravated by sedentary lifestyle induces chronic under-activation of AMPK, the master regulator of intracellular energy homeostasis. Sudden increase in chronic, dysregulated 'sterile' inflammatory disorders probably results from a shift towards calorie rich, sanitized, cushioned, injury/ infection free environment, repositioning inflammatory repair pathways towards chronic, non-microbial, 'sterile', 'low grade', and 'parainflammation'. AMPK, (at the helm of energy provisioning) supervises the metabolic regulation of inflammasome activation, a common denominator in lifestyle disorders.

DISCUSSION

In this review, we discuss various pathways linking AMPK under-activation and inflammasome activation. AMPK under-activation, the possible norm in energy-rich sedentary lifestyle, could be the central agency that stimulates inflammasome activation by multiple pathways such as 1: decreasing autophagy, and accumulation of intracellular DAMPs, (particulate crystalline molecules, advanced glycation end-products, oxidized lipids, etc.) 2: stimulating a glycolytic shift (pro-inflammatory) in metabolism, 3: promoting NF-kB activation and decreasing Nrf2 activation, 4: increasing reactive oxygen species (ROS) formation, Unfolded Protein Response (UPR) and Endoplasmic Reticulum (ER) stress.

CONCLUSION

The 'inverse energy crisis' associated with calorie-rich, sedentary lifestyle, advocates dietary and pharmacological interventions for treating chronic metabolic disorders by overcoming / reversing AMPK under-activation.

Inflammasomes: a preclinical assessment of targeting in atherosclerosis

INTRODUCTION

Inflammasomes are central to atherosclerotic vascular dysfunction with regulatory effects on inflammation, immune modulation, and lipid metabolism. The NLRP3 inflammasome is a critical catalyst for atherogenesis thus highlighting its importance in understanding the pathophysiology of atherosclerosis and for the identification of novel therapeutic targets and biomarkers for the treatment of cardiovascular disease.

AREAS COVERED

This review includes an overview of macrophage lipid metabolism and the role of NLRP3 inflammasome activity in cardiovascular inflammation and atherosclerosis. We highlight key activators, signal transducers and major regulatory components that are being considered as putative therapeutic targets for inhibition of NLRP3-mediated cardiovascular inflammation and atherosclerosis.

EXPERT OPINION

NLRP3 inflammasome activity lies at the nexus between inflammation and cholesterol metabolism; it offers unique opportunities for understanding atherosclerotic pathophysiology and identifying novel modes of treatment. As such, a host of NLRP3 signaling cascade components have been identified as putative targets for drug development. We catalog these current discoveries in therapeutic targeting of the NLRP3 inflammasome and, utilizing the CANTOS trial as the translational (bench-to-bedside) archetype, we examine the complexities, challenges, and ultimate goals facing the field of atherosclerosis research.

Mechanisms of diabetic cardiomyopathy and potential therapeutic strategies: preclinical and clinical evidence

The pathogenesis and clinical features of diabetic cardiomyopathy have been well-studied in the past decade, but effective approaches to prevent and treat this disease are limited. Diabetic cardiomyopathy occurs as a result of the dysregulated glucose and lipid metabolism associated with diabetes mellitus, which leads to increased oxidative stress and the activation of multiple inflammatory pathways that mediate cellular and extracellular injury, pathological cardiac remodelling, and diastolic and systolic dysfunction. Preclinical studies in animal models of diabetes have identified multiple intracellular pathways involved in the pathogenesis of diabetic cardiomyopathy and potential cardioprotective strategies to prevent and treat the disease, including antifibrotic agents, anti-inflammatory agents and antioxidants. Some of these interventions have been tested in clinical trials and have shown favourable initial results. In this Review, we discuss the mechanisms underlying the development of diabetic cardiomyopathy and heart failure in type 1 and type 2 diabetes mellitus, and we summarize the evidence from preclinical and clinical studies that might provide guidance for the development of targeted strategies. We also highlight some of the novel pharmacological therapeutic strategies for the treatment and prevention of diabetic cardiomyopathy.

Blueberry Extracts as a Novel Approach to Prevent Ozone-Induced Cutaneous Inflammasome Activation

The World Health Organization estimates that 7 million people die every year due to pollution exposure. Among the different pollutants to which living organism are exposed, ozone (O3) represents one of the most toxic, because its location which is the skin is one of the direct tissues exposed to the outdoor environment. Chronic exposure to outdoor stressors can alter cutaneous redox state resulting in the activation of inflammatory pathways. Recently, a new player in the inflammation mechanism was discovered: the multiprotein complex NLRP1 inflammasome, which has been shown to be also expressed in the skin. The topical application of natural compounds has been studied for the last 40 years as a possible approach to prevent and eventually cure skin conditions. Recently, the possibility to use blueberry (BB) extract to prevent pollution-induced skin toxicity has been of great interest in the cosmeceutical industry. In the present study, we analyzed the cutaneous protective effect of BB extract in several skin models (2D, 3D, and human skin explants). Specifically, we observed that in the different skin models used, BB extracts were able to enhance keratinocyte wound closure and normalize proliferation and migration responses previously altered by O3. In addition, pretreatment with BB extracts was able to prevent ozone-induced ROS production and inflammasome activation measured as NRLP1-ASC scaffold formation and also prevent the transcripts of key inflammasome players such as CASP1 and IL-18, suggesting that this approach as a possible new technology to prevent cutaneous pollution damage. Our data support the hypothesis that BB extracts can effectively reduce skin inflammation and be a possible new technology against cutaneous pollution-induced damage.

Mitochondrial Contact Sites in Inflammation-Induced Cardiovascular Disease

The mitochondrion, the ATP-producing center, is both physically and functionally associated with almost all other organelles in the cell. Mitochondrial-associated membranes (MAMs) are involved in a variety of biological processes, such as lipid exchange, protein transport, mitochondrial fission, mitophagy, and inflammation. Several inflammation-related diseases in the cardiovascular system involve several intracellular events including mitochondrial dysfunction as well as disruption of MAMs. Therefore, an in-depth exploration of the function of MAMs will be of great significance for us to understand the initiation, progression, and clinical complications of cardiovascular disease (CVD). In this review, we summarize the recent advances in our knowledge of MAM regulation and function in CVD-related cells. We discuss the potential roles of MAMs in activating inflammation to influence the development of CVD.

Bilirubin in metabolic syndrome and associated inflammatory diseases: New perspectives

Diabetes mellitus is one of the major global health issues, which is closely related to metabolic dysfunction and the chronic inflammatory diseases. Multiple studies have demonstrated that serum bilirubin is negatively correlated with metabolic syndrome and associated inflammatory diseases, including atherosclerosis, hypertension, etc. However, the roles of bilirubin in metabolic syndrome and associated inflammatory diseases still remain unclear. Here, we explain the role of bilirubin in metabolic syndrome and chronic inflammatory diseases and its therapeutic potential. Understanding the role of bilirubin activities in diabetes may serve as a therapeutic target for the treatment of chronic inflammatory diseases in diabetic patients.

Role of Caspase 1 in Ischemia/Reperfusion Injury of the Myocardium

Acute occlusion of a coronary artery can result in myocardial infarction-a leading cause of premature death. Prompt restoration of blood flow to the myocardium can prevent excessive death of cardiomyocytes and improve clinical outcome. Although the major mechanism of cell death after reperfusion is necrosis, it is now recognized that many other cell death pathways may be involved in ischemia-reperfusion (I/R) injury. Pyroptosis is one such cell death pathway that is caspase-1-dependent and induced in response to cellular insult. The activated caspase-1 protease cleaves and activates specific cellular targets including gasdermin D and the proinflammatory cytokines interleukin-1β and interleukin-18. The N-terminal fragment of gasdermin D forms plasma membrane pores resulting in cytosolic leakage and cell rupture, releasing interleukin-1β and interleukin-18. Evidence suggests that inflammation induced by I/R through the pyroptotic pathway contributes to cardiomyocyte death, excessive scar formation, and poor ventricular remodeling. For this reason, there is growing interest in targeting components of the pyroptotic pathway as a means of reducing I/R injury.

Focus on the Role of NLRP3 Inflammasome in Diseases

Inflammation is a protective reaction activated in response to detrimental stimuli, such as dead cells, irritants or pathogens, by the evolutionarily conserved immune system and is regulated by the host. The inflammasomes are recognized as innate immune system sensors and receptors that manage the activation of caspase-1 and stimulate inflammation response. They have been associated with several inflammatory disorders. The NLRP3 inflammasome is the most well characterized. It is so called because NLRP3 belongs to the family of nucleotide-binding and oligomerization domain-like receptors (NLRs). Recent evidence has greatly improved our understanding of the mechanisms by which the NLRP3 inflammasome is activated. Additionally, increasing data in animal models, supported by human studies, strongly implicate the involvement of the inflammasome in the initiation or progression of disorders with a high impact on public health, such as metabolic pathologies (obesity, type 2 diabetes, atherosclerosis), cardiovascular diseases (ischemic and non-ischemic heart disease), inflammatory issues (liver diseases, inflammatory bowel diseases, gut microbiome, rheumatoid arthritis) and neurologic disorders (Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis and other neurological disorders), compared to other molecular platforms. This review will provide a focus on the available knowledge about the NLRP3 inflammasome role in these pathologies and describe the balance between the activation of the harmful and beneficial inflammasome so that new therapies can be created for patients with these diseases.

The association between fat mass and subclinical atherosclerosis in healthy schoolchildren

BACKGROUND AND AIMS

Childhood obesity is associated with increased risk of cardiovascular disease (CVD) later in life. The aims of this study were to investigate the change of atherosclerosis risk factors in three fat mass percentiles and to examine the association between fat mass and atherosclerosis risk factors among a group of schoolchildren.

METHODS

A total of 125 schoolchildren (64 boys) aged 10-15 years were distributed into three groups: (i) the lower fat mass (LFM) group, for participants who reported fat mass ≤50th percentile; (ii) the middle fat mass (MFM) group, for participants who reported fat mass >50th percentile and <75th percentile; and (iii) the higher fat mass (HFM) group for participants who reported ≥ 75th percentiles. Measurements of carotid intima-media thickness (cIMT) using high-resolution B-mode ultrasound, lipemic profile, blood pressure, serum proinflammatory cytokines and soluble adhesion molecules were performed.

RESULTS

Significant differences (p ≤ 0.05) were shown between the three groups in total cholesterol (TC), triglycerides (TG), LDL, interlukien-6 (IL-6), and interlukien-1 beta (IL-1β). Using multiple linear regression analysis of fat mass as the dependent variable with the studied subclinical atherosclerosis risk, fat mass was significantly (p ≤ 0.05) associated with the variation expressed in systolic blood pressure (β = 0.490), diastolic blood pressure (β = 0.470), TC (β = 0.399), TG (β = 0.306), HDL (β = -0.281), LDL (β = 0.446), E-selectin (β = 0.314), and cIMT (β = 0.257).

CONCLUSION

Higher fat mass is associated with increased risk of atherosclerosis in schoolchildren. Atherosclerosis risk factors including biomarkers of inflammation, endothelial dysfunction, a state of dyslipidemia, increased cIMT, and high blood pressure were associated with fat mass. Studies evaluating the appropriate fat mass cut-off points in children and adolescents are needed.

Effect of time-restricted feeding on metabolic risk and circadian rhythm associated with gut microbiome in healthy males

Time-restricted feeding (TRF) confers protection against nutritional challenges that predispose obesity and metabolic risks through involvement of circadian locomotor output cycles protein kaput genes and gut microbiome, but the underlying mechanism is not clearly understood. Therefore, the present study examined the effects of TRF on metabolic markers and circadian rhythm associated with gut microbiota in healthy males. Two groups (TRF, n 56; non-TRF, n 24) of male adults were enrolled. The TRF group provided blood at pre-TRF and post-TRF, while non-TRF one time after 25 d of trial. Serum lipid and liver profiles were determined. Real time-PCR was applied for circadian and inflammatory gene expression. The 16S rRNA genes were sequenced on the Illumina Miseq v3 platform to comprehensively catalogue the composition and abundance of bacteria in stool. We showed that TRF ameliorated the serum lipid and liver profiles of the individuals. In the TRF group, gut microbial richness was significantly enhanced, with enrichment of Prevotellaceae and Bacteroideaceae. TRF enhanced circadian gene expression probably by activation of sirtuin-1, which is positively associated with gut microbiome richness. TRF could be a safe remedy for the prevention of metabolic diseases related to dyslipidaemia, as it regulates circadian rhythm associated with gut microbiome modulation.

LDL, LDL receptors, and PCSK9 as modulators of the risk for type 2 diabetes: a focus on white adipose tissue

Type 2 diabetes (T2D) and cardiovascular disease (CVD) share many risk factors such as obesity, unhealthy lifestyle, and metabolic syndrome, whose accumulation over years leads to disease onset. However, while lowering plasma low-density lipoprotein cholesterol (LDLC) is cardio-protective, novel evidence have recognised a role for common LDLC-lowering variants (e.g. in HMGCR, PCSK9, and LDLR) and widely used hypocholesterolemic drugs that mimic the effects of some of these variants (statins) in higher risk for T2D. As these conditions decrease plasma LDLC by increasing tissue-uptake of LDL, a role for LDL receptor (LDLR) pathway was proposed. While underlying mechanisms remain to be fully elucidated, work from our lab reported that native LDL directly provoke the dysfunction of human white adipose tissue (WAT) and the activation of WAT NLRP3 (Nucleotide-binding domain and Leucine-rich repeat Receptor, containing a Pyrin domain 3) inflammasome, which play a major role in the etiology of T2D. However, while elevated plasma numbers of apolipoprotein B (apoB)-containing lipoproteins (measured as apoB, mostly as LDL) is associated with WAT dysfunction and related risk factors for T2D in our cohort, this relation was strengthened in regression analysis by lower plasma proprotein convertase subtilisin/kexin type 9 (PCSK9). This supports a central role for upregulated pathway of LDLR and/or other receptors regulated by PCSK9 such as cluster of differentiation 36 (CD36) in LDL-induced anomalies. Targeting receptor-mediated uptake of LDL into WAT may reduce WAT inflammation, WAT dysfunction, and related risk for T2D without increasing the risk for CVD.

Tendril extract of Cucurbita moschata suppresses NLRP3 inflammasome activation in murine macrophages and human trophoblast cells

Inflammation is the root cause of many diseases that pose a serious threat to human health. Excessive inflammation can also result in preterm birth or miscarriage in pregnant women. Pumpkin (Cucurbita moschata Duchesne, CMD) is a well-known traditional health food and medicinal herb used in many countries to treat diabetes, obesity, osteoporosis, cancer and other diseases. In this study, we investigated the effects of hot water extract derived from the tendrils of C. moschata Duchesne (TCMD) on NLRP3 inflammasome activation in murine macrophages and human trophoblast cells. The TCMD treatment of LPS-primed bone marrow-derived macrophages (BMDMs) and human trophoblast cells attenuated NLRP3 inflammasome activation induced by inflammasome activators such as ATP, nigericin, and monosodium urate (MSU). TCMD treatment suppressed IL-1β secretion in a dose-dependent manner, without affecting IL-6 secretion. In addition, TCMD inhibited NLRP3-dependent pyroptosis in BMDMs. TCMD also suppressed the release of mature IL-1β and activation of cleaved-caspase-1 via limited ASC oligomerization. Furthermore, TCMD significantly inhibited IL-1β secretion and pyroptotic cell death in human trophoblast cells. These results suggest that TCMD exhibits anti-inflammatory effects mediated via inhibition of NLRP3 inflammasome activation suggesting therapeutic potential against inflammatory diseases, preterm birth, and miscarriage.

Intestinal Alkaline Phosphatase Deficiency Is Associated with Ischemic Heart Disease

Background

We have previously shown that the deficiency of the gut enzyme intestinal alkaline phosphatase (IAP) is associated with type 2 diabetes mellitus (T2DM) in humans, and mice deficient in IAP develop the metabolic syndrome, a precipitant of T2DM and ischemic heart disease (IHD). We hypothesized that IAP deficiency might also be associated with IHD in humans. We aimed to determine the correlation between the IAP level and IHD in humans.

Methods and Results

The IHD patients were recruited from the National Institute of Cardiovascular Diseases (NICVD), Dhaka, Bangladesh, and the control healthy participants were recruited from a suburban community of Dhaka. We determined the IAP level in the stools of 292 IHD patients (187 males, 105 females) and 331 healthy control people (84 males, 247 females). We found that compared to controls, IHD patients have approx. 30% less IAP (mean ± SEM: 63.7 ± 3.5 vs. 44.9 ± 2.1 U/g stool, respectively; p < 0.000001), which indicates that IAP deficiency is associated with IHD, and a high level of IAP is probably protective against IHD in humans. The adjusted generalized linear model (GLM) of regression analysis predicted a strong association of IAP with IHD (p = 0.0035). Multiple logistic regression analysis showed an independent inverse relationship between the IAP level and the IHD status (odds ratio, OR = 0.993 with 95% CI 0.987-0.998; p < 0.01).

Conclusions

IAP deficiency is associated with IHD, and a high level of IAP might be protective against IHD.

Inflammasome in HIV infection: Lights and shadows

The importance of inflammasome, and related cytokines IL-1ß and IL-18, in host defense against pathogens is well documented, however, at the same time, dysregulation of inflammasome has been associated to multifactorial diseases characterized by chronic inflammation (i.e.: metabolic disorders, cardiovascular diseases, neurodegenerative diseases, autoimmunity, cancer). Inflammasome activation has been described in response to HIV-1 and possibly contributes to the resistance against virus establishment, however, on the other hand, when viral infection becomes chronic, independently from antiretroviral therapy, the increase constitutive activation of inflammasome has been eventually associated to a worse prognosis, raising the question about the role played by inflammasome and/or some specific receptors in this context. Due to the chance to imply targeted therapies that inhibit inflammasome activation and/or cytokines release, it will be important to define the impact of the complex in the pathogenesis of HIV. The purpose of this review is to depict the double-faced inflammasome role in HIV-1 infection, trying to unveil whether besides its role in first line defense against the virus, it exerts a harmful effect during the chronic phase of infection.

Oral health assessment of independent elders in Texas

BACKGROUND

The oral health status of older adults in North Texas is largely unknown.

METHODS

This cross-sectional, pilot study used the Basic Screening Survey for older adults involving a self-administered questionnaire and oral screening examination of 155 adults aged 65 years and older, in four Dallas, TX settings, stratified socioeconomically. Recruitment occurred from July 2012 through March 2014.

RESULTS

Participants were between 65 and 90 years of age. The sample was predominantly female (64%), reflecting Texas population diversity with 49.7% White, 34.2% Hispanic, 14.2% Black, and 1.8% others. Missing teeth number (P < .019), functional contacts, untreated decay, root decay (P < .05), tooth mobility, root fragments and need for emergency treatment (P < .021) differed significantly regarding site and ethnicity. Participants at the least affluent sites (two) evidenced significant unmet dental needs and suboptimal access to care. In contrast, those at the most affluent sites (also oldest participants) had good oral health and access to care.

CONCLUSIONS

There are profound oral health disparities in urban North Texas based on socioeconomic status. These findings suggest that poor oral health is not inevitable in the elderly, as long as there is access to care. Larger-scale studies are required to broadly address oral health disparities among elderly Texans.

Chlamydia and Lipids Engage a Common Signaling Pathway That Promotes Atherogenesis

BACKGROUND

Recent studies indicate that Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) signaling promote the development of high fat diet-induced atherosclerosis in hypercholesterolemic mice.

OBJECTIVES

The authors investigated the role of TLR4/MyD88 signaling in hematopoietic and stromal cells in the development and infection-mediated acceleration of atherosclerosis.

METHODS

The authors generated bone marrow chimeras between wild-type and Tlr4^-/- mice, as well as wild-type and Myd88^-/- mice. All mice were on the Apoe^-/- background and fed high fat diet. The authors infected the chimeric mice with C. pneumoniae (CP) and fed them high fat diet.

RESULTS

Aortic sinus plaques and lipid content were significantly reduced in Apoe^-/- mice that received Tlr4^-/-or Myd88^-/- bone marrow compared with control animals despite similar cholesterol levels. Similarly, Tlr4 or Myd88 deficiency in stromal cells also led to a reduction in the lesion area and lipid in aortic sinus plaques. MyD88 expression only in CD11c+ dendritic cells (myeloid cells) in cells was sufficient in otherwise MyD88-deficient mice to induce CP infection-mediated acceleration of atherosclerosis, underlining the key role of MyD88 in CD11c+ dendritic cells (myeloid cells). Whereas CP infection markedly accelerated atherosclerosis in TLR4- or MyD88-positive chimeras, CP infection had a minimal effect on atherosclerosis in TLR4- or MyD88-deficient mice (either in the hematopoietic or stromal cell compartments).

CONCLUSIONS

The authors show that both CP infection and metabolic stress associated with dyslipidemia use the same innate immune response pathway, utilizing TLR4/MyD88 signaling, with similar relative contributions in bone marrow-derived hematopoietic cells and in stromal cells. Further studies are required to understand this intricate and complex cross talk among innate and adaptive immune systems in various conditions to more effectively design dendritic cell-mediated atheroprotective vaccines and other therapeutic strategies.