Glyburide is anti-inflammatory and associated with reduced mortality in melioidosis

Identification of ZIP8-induced ferroptosis as a major type of cell death in monocytes under sepsis conditions

Sepsis is a heterogenous syndrome with concurrent hyperinflammation and immune suppression. A prominent feature of immunosuppression during sepsis is the dysfunction and loss of monocytes; however, the major type of cell death contributing to this depletion, as well as its underlying molecular mechanisms, are yet to be identified. In this study, we confirmed the monocyte loss in septic patients based on a pooled gene expression data of periphery leukocytes. Using the collected reference gene sets from databases and published studies, we identified ferroptosis with a greater capacity to distinguish between sepsis and control samples than other cell death types. Further investigation on the molecular drivers, by a genetic algorithm-based feature selection and a weighted gene co-expression network analysis, revealed that zrt-/irt-like protein 8 (ZIP8), encoded by SLC39A8, was closely associated with ferroptosis of monocytes during sepsis. We validated the increase of ZIP8 of monocytes with in vivo and in vitro experiments. The in vitro studies also showed that downregulation of ZIP8 alleviated the lipopolysaccharide-induced lipid peroxidation, as well as restoring the reduction of GPX4, FTH1 and xCT. These findings suggest that ferroptosis might be a key factor in the loss of monocytes during sepsis, and that the heightened expression of ZIP8 may facilitate this progression.

Improving the clinical recognition, prognosis, and treatment of melioidosis through epidemiology and clinical findings: The Sabah perspective

INTRODUCTION

Melioidosis is a deadly endemic disease in northern Australia and Southeast Asia, including Sabah, Malaysia, which is caused by the bacterium Burkholderia pseudomallei. It contributes to high fatality rates, mainly due to misdiagnosis leading to the wrong treatment being administered to the patients. Local epidemiology and data on clinical features could assist clinicians during diagnosis and treatment. However, these details are still scarce, particularly in Sabah.

METHODS

A retrospective study of 246 culture-confirmed melioidosis cases in Queen Elizabeth Hospital, Sabah, Malaysia was performed between 2016 and 2018. The epidemiological data and clinical and laboratory findings were extracted and analysed.

RESULTS

The annual incidence of culture-confirmed melioidosis cases was estimated to be 4.97 per 100,000 people. The mean age of the patients was 50±15 years. Males and members of the Kadazan-Dusun ethnic group accounted for the majority of the melioidosis cases. The odds ratio analysis indicated that bacteraemic melioidosis in this region was significantly associated with fever (76%), and patients having at least one underlying illness (43%), including diabetes mellitus (32%). Sixty-eight patients (28%) succumbed to melioidosis. Contrary to what is known regarding factors that promote bacteraemic melioidosis, neither patients with fever nor patients with at least one comorbid disease, including diabetes mellitus, were significantly associated with death from melioidosis. There was no statistically significant difference between patients without comorbidities (24, 27%) and those with at least one comorbid disease (26, 25%), including diabetes mellitus (18, 23%). The odds ratios indicate that melioidosis mortality in this region is related to patients showing respiratory organ-associated symptoms (29%), bacteraemia (30%), and septic shock (47%). Burkholderia pseudomallei isolates in this study were highly susceptible to ceftazidime (100%), imipenem (100%), and trimethoprim-sulfamethoxazole (98%).

CONCLUSIONS

Information obtained from this study can be used by clinicians to recognise individuals with the highest risk of acquiring melioidosis, estimate an accurate prognosis, and provide effective treatment for melioidosis patients to reduce death from melioidosis.

Characteristics and One Year Outcomes of Melioidosis Patients in Northeastern Thailand: A Prospective, Multicenter Cohort Study

Background

Melioidosis is a neglected tropical infection caused by the environmental saprophyte Burkholderia pseudomallei.

Methods

We conducted a prospective, observational study at nine hospitals in northeastern Thailand, a hyperendemic melioidosis zone, to define current characteristics of melioidosis patients and quantify outcomes over one year.

Findings

2574 individuals hospitalised with culture-confirmed melioidosis were screened and 1352 patients were analysed. The median age was 55 years, 975 (72%) were male, and 951 (70%) had diabetes. 565 (42%) patients presented with lung infection, 1042 (77%) were bacteremic, 442 (33%) received vasopressors/inotropes and 547 (40%) received mechanical ventilation. 1307 (97%) received an intravenous antibiotic against B. pseudomallei. 335/1345 (25%) patients died within one month and 448/1322 (34%) of patients died within one year. Most patients had risk factors for melioidosis, but patients without identified risk factors did not have a reduced risk of death. Of patients discharged alive, most received oral trimethoprim-sulfamethoxazole, which was associated with decreased risk of post-discharge death; 235/970 (24%) were readmitted, and 874/1015 (86%) survived to one year. Recurrent infection was detected in 17/994 patients (2%). Patients with risk factors other than diabetes had increased risk of death and increased risk of hospital readmission.

Interpretation

In northeastern Thailand patients with melioidosis experience high rates of bacteremia, organ failure and death. Most patients discharged alive survive one year although all-cause readmission is common. Recurrent disease is rare. Strategies that emphasize prevention, rapid diagnosis and intensification of early clinical management are likely to have greatest impact in this and other resource-restricted regions.

Funding

US NIH/NIAID U01AI115520.

NLRP3 and pyroptosis blockers for treating inflammatory diseases

The nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) inflammasome has emerged as a key mediator of pathological inflammation in many diseases and is an exciting drug target. Here, we review the molecular basis of NLRP3 inhibition by drug-like small molecules under development as novel therapeutics. We also summarize recent strategies to block pyroptosis as a novel approach to suppress chronic inflammation. Major recent developments in this area include the elucidation of mechanisms of action (MoAs) by which small molecules block NLRP3 inflammasome assembly and gasdermin D (GSDMD)-induced pyroptosis. We also discuss the status of clinical trials using agents that block specific components of the NLRP3 pathway, including their potential clinical applications for the treatment of many diseases.

Glucose-lowering drugs and outcome from COVID-19 among patients with type 2 diabetes mellitus: a population-wide analysis in Hong Kong

OBJECTIVES

To investigate the association between baseline use of glucose-lowering drugs and serious clinical outcome among patients with type 2 diabetes.

DESIGN

Territory-wide retrospective cohort of confirmed cases of COVID-19 between January 2020 and February 2021.

SETTING

All public health facilities in Hong Kong.

PARTICIPANTS

1220 patients with diabetes who were admitted for confirmed COVID-19.

PRIMARY AND SECONDARY OUTCOME MEASURES

Composite clinical endpoint of intensive care unit admission, requirement of invasive mechanical ventilation and/or in-hospital death.

RESULTS

In this cohort (median age 65.3 years, 54.3% men), 737 (60.4%) patients were treated with metformin, 385 (31.6%) with sulphonylureas, 199 (16.3%) with dipeptidyl peptidase-4 (DPP-4) inhibitors and 273 (22.4%) with insulin prior to admission. In multivariate Cox regression, use of metformin and DPP-4 inhibitors was associated with reduced incidence of the composite endpoint relative to non-use, with respective HRs of 0.51 (95% CI 0.34 to 0.77, p=0.001) and 0.46 (95% CI 0.29 to 0.71, p<0.001), adjusted for age, sex, diabetes duration, glycated haemoglobin (HbA1c), smoking, comorbidities and drugs. Use of sulphonylureas (HR 1.55, 95% CI 1.07 to 2.24, p=0.022) and insulin (HR 6.34, 95% CI 3.72 to 10.78, p<0.001) were both associated with increased hazards of the composite endpoint.

CONCLUSIONS

Users of metformin and DPP-4 inhibitors had fewer adverse outcomes from COVID-19 compared with non-users, whereas insulin and sulphonylurea might predict a worse prognosis.

Identification of Dual-Target Compounds with Antifungal and Anti-NLRP3 Inflammasome Activity

Invasive and superficial infections caused by the Candida species result in significant global morbidity and mortality. As the pathogenicity of these organisms is intimately intertwined with host immune response, therapies to target both the fungus and host inflammation may be warranted. Structural similarities exist between established inhibitors of the NLRP3 inflammasome and those of fungal acetohydroxyacid synthase (AHAS). Therefore, we leveraged this information to conduct an in silico molecular docking screen to find novel polypharmacologic inhibitors of these targets that resulted in the identification of 12 candidate molecules. Of these, compound 10 significantly attenuated activation of the NLPR3 inflammasome by LPS + ATP, while also demonstrating growth inhibitory activity against C. albicans that was alleviated in the presence of exogenous branched chain amino acids, consistent with targeting of fungal AHAS. SAR studies delineated an essential molecular scaffold required for dual activity. Ultimately, 10 and its analog 10a resulted in IC₅₀ (IL-1β release) and MIC₅₀ (fungal growth) values with low μM potency against several Candida species. Collectively, this work demonstrates promising potential of dual-target approaches for improved management of fungal infections.

Glyburide attenuates B(a)p and LPS-induced inflammation-related lung tumorigenesis in mice

Glyburide (Gly) could inhibit NLRP3 inflammasome, as well as could be treated with Type 2 diabetes as a common medication. Despite more and more studies show that Gly could influence cancer risk and tumor growth, it remains unclear about the effect of Gly in lung tumorigenesis. To evaluate whether Gly inhibited lung tumorigenesis and explore the possible mechanisms, a benzo(a)pyrene [B(a)p] plus lipopolysaccharide (LPS)-induced non-diabetes mice model was established with B(a)p for 4 weeks and once a week (1 mg/mouse), then instilled with LPS for 15 weeks and once every 3 weeks (2.5 μg/mouse) intratracheally. Subsequently, Gly was administered by gavage (10 μl/g body weight) 1 week before B(a)p were given to the mice until the animal model finished (when Gly was first given named Week 0). At the end of the experiment called Week 34, we analyzed the incidence, number and histopathology of lung tumors, and detected the expression of NLRP3, IL-1β, and Cleaved-IL-1β protein. We found that vehicles and tricaprylin+Gly could not cause lung carcinogenesis in the whole process. While the incidence and mean tumor count of mice in B(a)P/LPS+Gly group were decreased compared with B(a)p/LPS group. Moreover, Gly could alleviate inflammatory changes and reduce pathological tumor nest numbers compared with mice administrated with B(a)p/LPS in histopathological examination. The B(a)p/LPS increased the expression of NLRP3, IL-1β, and Cleaved-IL-1β protein significantly than Vehicle, whereas decreased in B(a)P/LPS+Gly (0.96 mg/kg) group compared with B(a)p/LPS group. Results suggested glyburide might inhibit NLRP3 inflammasome to attenuate inflammation-related lung tumorigenesis caused by intratracheal instillation of B(a)p/LPS in non-diabetes mice.

The Cox model of predicting mortality among melioidosis patients in Northern Malaysia: A retrospective study

ABSTRACT

Melioidosis is an infectious disease that is initiated by a bacteria recognized as Burkholderia pseudomallei. Despite the high fatality rate from melioidosis, there is a minimal published study about the disease in Malaysia.This study aimed to identify the prognostic factors of mortality among melioidosis patients in northern Malaysia.All inpatient patients who were admitted to Hospital Sultanah Bahiyah, Kedah and Hospital Tuanku Fauziah, Perlis with culture-confirmed melioidosis during the period 2014 to 2017 were included in the study. The study retrospectively collected 510 melioidosis patients from the Melioidosis Registry. Hazard ratio (HR) used in advanced multiple Cox regression was used to obtain the final model of prognostic factors of melioidosis. The analysis was performed using STATA/SE 14.0 for Windows software.From the results, among the admitted patients, 50.1% died at the hospital. The mean age for those who died was 55 years old, and they were mostly male. The most common underlying disease was diabetes mellitus (69.8%), followed by hypertension (32.7%). The majority of cases (86.8%) were bacteremic. The final Cox model identified 5 prognostic factors of mortality among melioidosis patients. The factors were diabetes mellitus, type of melioidosis, platelet count, white blood cell count, and urea value. The results showed that bacteremic melioidosis increased the risk of dying by 3.47 (HR: 3.47, 95% confidence intervals [CI]: 1.67-7.23, P = .001) compared to non-bacteremic melioidosis. Based on the blood investigations, the adjusted HRs from the final model showed that all 3 blood investigations were included as the prognostic factors for the disease (low platelet: HR = 1.76, 95% CI: 1.22-2.54, P = .003; high white blood cell: HR = 1.49, 95% CI 1.06-2.11, P = .023; high urea: HR = 2.92, 95% CI: 1.76-4.85, P < .001; and low level of urea: HR = 2.69, 95% CI: 1.69-4.29, P < .001). By contrast, melioidosis patients with diabetic had 30.0% lower risk of dying from melioidosis compared to those with non-diabetic (HR = 0.70, 95% CI: 0.52-0.94, P = .016).Identifying the prognostic factors of mortality in patients with melioidosis allows a guideline of early management in these patients, which may improve patient's survival.

Gestational Diabetes Mellitus and Maternal Immune Dysregulation: What We Know So Far

Gestational diabetes mellitus (GDM) is an obstetric complication that affects approximately 5-10% of all pregnancies worldwide. GDM is defined as any degree of glucose intolerance with onset or first recognition during pregnancy, and is characterized by exaggerated insulin resistance, a condition which is already pronounced in healthy pregnancies. Maternal hyperglycaemia ensues, instigating a 'glucose stress' response and concurrent systemic inflammation. Previous findings have proposed that both placental and visceral adipose tissue play a part in instigating and mediating this low-grade inflammatory response which involves altered infiltration, differentiation and activation of maternal innate and adaptive immune cells. The resulting maternal immune dysregulation is responsible for exacerbation of the condition and a further reduction in maternal insulin sensitivity. GDM pathology results in maternal and foetal adverse outcomes such as increased susceptibility to diabetes mellitus development and foetal neurological conditions. A clearer understanding of how these pathways originate and evolve will improve therapeutic targeting. In this review, we will explore the existing findings describing maternal immunological adaption in GDM in an attempt to highlight our current understanding of GDM-mediated immune dysregulation and identify areas where further research is required.

Host-directed Therapy: A New Arsenal to Come

The emergence of drug-resistant strains among the variety of pathogens worsens the situation in today's scenario. In such a situation, a very heavy demand for developing the new antibiotics has arisen, but unfortunately, very limited success has been achieved in this arena till now. Infectious diseases usually make their impression in the form of severe pathology. Intracellular pathogens use the host's cell machinery for their survival. They alter the gene expression of several host's pathways and endorse to shut down the cell's innate defense pathway like apoptosis and autophagy. Intracellular pathogens are co-evolved with hosts and have a striking ability to manipulate the host's factors. They also mimic the host molecules and secrete them to prevent the host's proper immune response against them for their survival. Intracellular pathogens in chronic diseases create excessive inflammation. This excessive inflammation manifests in pathology. Host directed therapy could be alternative medicine in this situation; it targets the host factors, and abrogates the replication and persistence of pathogens inside the cell. It also provokes the anti-microbial immune response against the pathogen and reduces the exacerbation by enhancing the healing process to the site of pathology. HDT targets the host's factor involved in a certain pathway that ultimately targets the pathogen life cycle and helps in eradication of the pathogen. In such a scenario, HDT could also play a significant role in the treatment of drugsensitive as well with drug resistance strains because it targets the host's factors, which favors the pathogen survival inside the cell.

Burkholderia pseudomallei sepsis with osteoarticular melioidosis of the hip in a patient with diabetes mellitus

Melioidosis is caused by the tropical soil pathogen Burkholderia pseudomallei Infection, usually in the form of pneumonia, disproportionately affects people with a risk factor for immune dysregulation and mortality remains high even with treatment. Climate change and increasing rates of diabetes render the populations of endemic areas increasingly vulnerable to the disease, which is emerging as a serious global health threat. We present here a case of a 68-year-old man from northern Australia with sepsis and osteoarticular melioidosis of the hip, and explore the links between diabetes mellitus and melioidosis, particularly with respect to musculoskeletal infection.

Effects of Sulfonylureas on Periodontopathic Bacteria-Induced Inflammation

Interleukin-1β (IL-1β) is an inflammatory cytokine produced by monocytes/macrophages and is closely associated with periodontal diseases. The NLRP3 inflammasome is involved in IL-1β activation through pro-IL-1β processing and pyroptotic cell death in bacterial infection. Recently, glyburide, a hypoglycemic sulfonylurea, has been reported to reduce IL-1β activation by suppressing activation of the NLRP3 inflammasome. Therefore, we evaluated the possibility of targeting the NLRP3 inflammasome pathway by glyburide to suppress periodontal pathogen-induced inflammation. THP-1 cells (a human monocyte cell line) were differentiated to macrophage-like cells by treatment with phorbol 12-myristate 13-acetate and stimulated by periodontopathic bacteria, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, or Fusobacterium nucleatum, in the presence of glyburide. IL-1β and caspase-1 expression in the cells and culture supernatants were analyzed by Western blotting and enzyme-linked immunosorbent assay, and cell death was analyzed by lactate dehydrogenase assay. Stimulation of THP-1 macrophage-like cells with every periodontopathic bacteria induced IL-1β secretion without cell death, which was suppressed by the NLRP3 inhibitor, MCC950, and caspase-1 inhibitor, z-YVAD-FMK. Glyburide treatment suppressed IL-1β expression in culture supernatants and enhanced intracellular IL-1β expression, suggesting that glyburide may have inhibited IL-1β secretion. Subsequently, a periodontitis rat model was generated by injecting periodontal bacteria into the gingiva, which was analyzed histologically. Oral administration of glyburide significantly suppressed the infiltration of inflammatory cells and the number of osteoclasts in the alveolar bone compared with the control. In addition to glyburide, glimepiride was shown to suppress the release of IL-1β from THP-1 macrophage-like cells, whereas other sulfonylureas (tolbutamide and gliclazide) or other hypoglycemic drugs belonging to the biguanide family, such as metformin, failed to suppress IL-1β release. Our results suggest that pharmacological targeting of the NLRP3 pathway may be a strategy for suppressing periodontal diseases.

Human Melioidosis

The causative agent of melioidosis, Burkholderia pseudomallei, a tier 1 select agent, is endemic in Southeast Asia and northern Australia, with increased incidence associated with high levels of rainfall. Increasing reports of this condition have occurred worldwide, with estimates of up to 165,000 cases and 89,000 deaths per year. The ecological niche of the organism has yet to be clearly defined, although the organism is associated with soil and water. The culture of appropriate clinical material remains the mainstay of laboratory diagnosis. Identification is best done by phenotypic methods, although mass spectrometric methods have been described. Serology has a limited diagnostic role. Direct molecular and antigen detection methods have limited availability and sensitivity. Clinical presentations of melioidosis range from acute bacteremic pneumonia to disseminated visceral abscesses and localized infections. Transmission is by direct inoculation, inhalation, or ingestion. Risk factors for melioidosis include male sex, diabetes mellitus, alcohol abuse, and immunosuppression. The organism is well adapted to intracellular survival, with numerous virulence mechanisms. Immunity likely requires innate and adaptive responses. The principles of management of this condition are drainage and debridement of infected material and appropriate antimicrobial therapy. Global mortality rates vary between 9% and 70%. Research into vaccine development is ongoing.

The double burden of diabetes and global infection in low and middle-income countries

Four out of five people in the world with diabetes now live in low- and middle-income countries (LMIC), and the incidence of diabetes is accelerating in poorer communities. Diabetes increases susceptibility to infection and worsens outcomes for some of the world’s major infectious diseases such as tuberculosis, melioidosis and dengue, but the relationship between diabetes and many neglected tropical diseases is yet to be accurately characterised. There is some evidence that chronic viral infections such as hepatitis B and HIV may predispose to the development of type 2 diabetes by chronic inflammatory and immunometabolic mechanisms. Helminth infections such as schistosomiasis may be protective against the development of diabetes, and this finding opens up new territory for discovery of novel therapeutics for the prevention and treatment of diabetes. A greater understanding of the impact of diabetes on risks and outcomes for infections causing significant diseases in LMIC is essential in order to develop vaccines and therapies for the growing number of people with diabetes at risk of infection, and to prioritise research agendas, public health interventions and policy. This review seeks to give an overview of the current international diabetes burden, the evidence for interactions between diabetes and infection, immune mechanisms for the interaction, and potential interventions to tackle the dual burden of diabetes and infection.

Second-Generation Antidiabetic Sulfonylureas Inhibit Candida albicans and Candidalysin-Mediated Activation of the NLRP3 Inflammasome

Repurposing of currently approved medications is an attractive option for the development of novel treatment strategies against physiological and infectious diseases. The antidiabetic sulfonylurea glyburide has demonstrated off-target capacity to inhibit activation of the NLRP3 inflammasome in a variety of disease models, including vaginal candidiasis, caused primarily by the fungal pathogen Candida albicans Therefore, we sought to determine which of the currently approved sulfonylurea drugs prevent the release of interleukin 1β (IL-1β), a major inflammasome effector, during C. albicans challenge of the human macrophage-like THP1 cell line. Findings revealed that the second-generation antidiabetics (glyburide, glisoxepide, gliquidone, and glimepiride), which exhibit greater antidiabetic efficacy than prior iterations, demonstrated anti-inflammatory effects with various degrees of potency as determined by calculation of 50% inhibitory concentrations (IC₅₀s). These same compounds were also effective in reducing IL-1β release during noninfectious inflammasome activation (e.g., induced by lipopolysaccharide [LPS] plus ATP), suggesting that their anti-inflammatory activity is not specific to C. albicans challenge. Moreover, treatment with sulfonylurea drugs did not impact C. albicans growth and filamentation or THP1 viability. Finally, the use of ECE1 and Candidalysin deletion mutants, along with isogenic NLRP3^-/- cells, demonstrated that both Candidalysin and NLRP3 are required for IL-1β secretion, further confirming that sulfonylureas suppress inflammasome signaling. Moreover, challenge of THP1 cells with synthetic Candidalysin peptide demonstrated that this toxin is sufficient to activate the inflammasome. Treatment with the experimental inflammasome inhibitor MCC950 led to similar blockade of IL-1β release, suggesting that Candidalysin-mediated inflammasome activation can be inhibited independently of potassium efflux. Together, these results demonstrate that the second-generation antidiabetic sulfonylureas retain anti-inflammatory activity and may be considered for repurposing against immunopathological diseases, including vaginal candidiasis.

Glibenclamide ameliorates transplant-induced arteriosclerosis and inhibits macrophage migration and MCP-1 expression

AIMS

Glibenclamide, a diabetes mellitus type 2 medication, has anti-inflammatory and autoimmune properties. This study investigated the effects of glibenclamide on transplant-induced arteriosclerosis as well as the underlying molecular events.

METHODS

Male C57Bl/6 (H-2b) and BALB/c (H-2d) mice were used for aorta transplantation. We used hematoxylin and eosin (HE) and Elastic Van Gieson (EVG) staining for histological assessment, and qRT-PCR and ELISA to measure mRNA and protein levels. Mouse peritoneal macrophages were isolated for lipopolysaccharide (LPS) stimulation and glibenclamide treatment followed by ELISA, Western blot, and Transwell assays.

RESULTS

Glibenclamide inhibited transplant-induced arteriosclerosis in vivo. Morphologically, glibenclamide reduced inflammatory cell accumulation and collagen deposition in the aortas. At the gene level, glibenclamide suppressed aortic cytokine mRNA levels, including interleukin-1β (IL-1β; 10.64 ± 3.19 vs. 23.77 ± 5.72; P < .05), tumor necrosis factor-α (TNF-α; 4.59 ± 0.78 vs. 13.89 ± 5.42; P < .05), and monocyte chemoattractant protein-1 (MCP-1; 202.66 ± 23.44 vs. 1172.73 ± 208.80; P < .01), while IL-1β, TNF-α, and MCP-1 levels were also reduced in the mouse sera two weeks after glibenclamide treatment (IL-1β, 39.40 ± 13.56 ng/ml vs. 78.96 ± 9.39 ng/ml; P < .01; TNF-α, 52.60 ± 13.00 ng/ml vs. 159.73 ± 6.76 ng/ml; P < .01; and MCP-1, 56.60 ± 9.07 ng/ml vs. 223.07 ± 36.28 ng/ml; P < .001). Furthermore, glibenclamide inhibited macrophage expression and secretion of inflammatory factors in vitro through suppressing activation of the nuclear factor-κB (NF-κB) pathway and MCP-1 production.

CONCLUSION

Glibenclamide protected against aorta transplantation-induced arteriosclerosis by reducing inflammatory factors in vivo and inhibited macrophage migration and MCP-1 production in vitro.

Emerging role of biologics for the treatment of melioidosis and glanders

Introduction: Two important pathogenic species within the genus Burkholderia, namely Burkholderia pseudomallei (Bpm) and Burkholderia mallei (Bm), are the causative agents of the life-threatening diseases melioidosis and glanders, respectively. Due to their high mortality rate and potential for aerosolization, they have gained interest as potential biothreat agents and are classified as Tier 1 Select Agents.Areas covered: The manuscript provides an overview of the literature covering the efforts taken in the last 10 years to develop new therapeutics measures against both Bpm and Bm, with attention on novel therapeutic agents.Expert Opinion: As a result of the complicated antibiotic regimens necessary to treat these infections, development of novel therapeutics is needed to treat both diseases. In recent years, the understanding of the pathogenesis of Burkholderia has improved significantly and so have the efforts to develop novel therapeutic agents with high efficacy, either alone, or in combination with conventional antibiotics.

Host-Targeted Therapeutics against Multidrug Resistant Intracellular Staphylococcus aureus

Staphylococcus aureus is a facultative intracellular pathogen that invades and replicates within many types of human cells. S. aureus has shown to rapidly overcome traditional antibiotherapy by developing multidrug resistance. Furthermore, intracellular S. aureus is protected from the last-resort antibiotics—vancomycin, daptomycin, and linezolid—as they are unable to achieve plasma concentrations sufficient for intracellular killing. Therefore, there is an urgent need to develop novel anti-infective therapies against S. aureus infections. Here, we review the current state of the field and highlight the exploitation of host-directed approaches as a promising strategy going forward.

Clinical Epidemiology of 7126 Melioidosis Patients in Thailand and the Implications for a National Notifiable Diseases Surveillance System

Background

National notifiable diseases surveillance system (NNDSS) data in developing countries are usually incomplete, yet the total number of fatal cases reported is commonly used in national priority-setting. Melioidosis, an infectious disease caused by Burkholderia pseudomallei, is largely underrecognized by policy-makers due to the underreporting of fatal cases via the NNDSS.

Methods

Collaborating with the Epidemiology Division (ED), Ministry of Public Health (MoPH), we conducted a retrospective study to determine the incidence and mortality of melioidosis cases already identified by clinical microbiology laboratories nationwide. A case of melioidosis was defined as a patient with any clinical specimen culture positive for B. pseudomallei. Routinely available microbiology and hospital databases of secondary care and tertiary care hospitals, the national death registry, and NNDSS data were obtained for analysis.

Results

A total of 7126 culture-confirmed melioidosis patients were identified from 2012 to 2015 in 60 hospitals countrywide. The total number of cases diagnosed in Northeast, Central, South, East, North, and West Thailand were 5475, 536, 374, 364, 358, and 19 cases, respectively. The overall 30-day mortality was 39% (2805/7126). Only 126 (4%) deaths were reported to the NNDSS. Age, presentation with bacteremia and pneumonia, prevalence of diabetes, and 30-day mortality differed by geographical region (all P < .001). The ED at MoPH has agreed to include the findings of our study in the next annual report of the NNDSS.

Conclusions

Melioidosis is an important cause of death in Thailand nationwide, and its clinical epidemiology may be different by region. In developing countries, NNDSS data can be supplemented by integrating information from readily available routine data sets.

Thrombocytopenia Impairs Host Defense Against Burkholderia pseudomallei (Melioidosis)

Background

Infection with the gram-negative bacillus Burkholderia pseudomallei (melioidosis) is an important cause of pneumosepsis in Southeast Asia and has a mortality of up to 40%. We aimed to assess the role of platelets in the host response against B. pseudomallei infection.

Methods

Association between platelet counts and mortality was determined in 1160 patients with culture-proven melioidosis. Mice treated with (low- or high-dose) platelet-depleting antibody were inoculated intranasally with B. pseudomallei and killed. Additional studies using functional glycoprotein Ibα-deficient mice were conducted.

Results

Thrombocytopenia was present in 31% of patients at admission and predicted mortality in melioidosis patients even after adjustment for confounders. In our murine-melioidosis model, platelet counts decreased, and mice treated with a platelet-depleting antibody showed enhanced mortality and higher bacterial loads compared to mice with normal platelet counts. Low platelet counts had a modest impact on early-pulmonary neutrophil influx. Reminiscent of their role in hemostasis, platelet depletion impaired vascular integrity, resulting in early lung bleeding. Glycoprotein Ibα-deficient mice had reduced platelet counts during B. pseudomallei infection together with an impaired local host defense in the lung.

Conclusions

Thrombocytopenia predicts mortality in melioidosis patients and, during experimental melioidosis, platelets play a protective role in both innate immunity and vascular integrity.

Longitudinal profiling of plasma cytokines in melioidosis and their association with mortality: a prospective cohort study

OBJECTIVES

To characterize plasma cytokine responses in melioidosis and analyse their association with mortality.

METHODS

A prospective longitudinal study was conducted in two hospitals in Northeast Thailand to enrol 161 individuals with melioidosis, plus 13 uninfected healthy individuals and 11 uninfected individuals with diabetes to act as controls. Blood was obtained from all individuals at enrolment (day 0), and at days 5, 12 and 28 from surviving melioidosis patients. Interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, IL-17A, IL-23, and tumour necrosis factor-α (TNF-α) were assayed in plasma. The association of each cytokine and its dynamics with 28-day mortality was determined.

RESULTS

Of the individuals with melioidosis, 131/161 (81%) were bacteraemic, and 68/161 (42%) died. On enrolment, median levels of IFN-γ, IL-6, IL-8, IL-10, IL-23 and TNF-α were higher in individuals with melioidosis compared with uninfected healthy individuals and all but IFN-γ were positively associated with 28-day mortality. Interleukin-8 provided the best discrimination of mortality (area under the receiver operating characteristic curve 0.78, 95% CI 0.71-0.85). Over time, non-survivors had increasing IL-6, IL-8 and IL-17A levels, in contrast to survivors. In joint modelling, temporal trajectories of IFN-γ, IL-6, IL-8, IL-10 and TNF-α predicted survival.

CONCLUSIONS

In a severely ill cohort of individuals with melioidosis, specific pro- and anti-inflammatory and T helper type 17 cytokines were associated with survival from melioidosis, at enrolment and over time. Persistent inflammation preceded death. These findings support further evaluation of these mediators as prognostic biomarkers and to guide targeted immunotherapeutic development for severe melioidosis.

Data on microbial DNA-induced IL-1β production in monocytes of type 1 diabetes patients

Inflammasomes are large protein complexes involved in the maturation of IL-1β, a cytokine associated with the pathophysiology of type 1 diabetes (T1D). The data presented in this article focused on the role of inflammasomes in DNA recognition in T1D patients. This data extend knowledge on DNA sensing in T1D patients and relate to our research paper "Monocytes contribute to DNA sensing through the TBK1 signaling pathway in type 1 diabetes patients" Zentsova et al., 2009. To examine inflammasome involvement, we blocked the known mechanism of inflammasome activation - potassium efflux via various approaches: 1) high concentration of KCl; 2) Glybenclamide, which selectively blocks the ATP sensitive K+ channel; 3) KN-62, an inhibitor of P2X7 receptor, which activates K+ channel after ATP binding. Moreover, we used an inhibitor which blocks Nod-like receptor family containing pyrin domain 3 (NLRP3) inflammasome. In T1D patients, we show that secretion of cytokines IL-1β, TNFα, IL-6 and IFNα after microbial DNA stimulation is promoted by potassium efflux and is not dependent on P2X7 receptor signaling. Surprisingly, the microbial DNA induced IL-1β release was independent of NLRP3.

NLRP3 inflammasome inhibitor glyburide expedites diabetic-induced impaired fracture healing

Localized inflammation is accompanied by the diabetic-induced fracture. The present study aims to investigate the therapeutic effects of glyburide, an NLRP3 inflammasome inhibitor, in a diabetic-induced fracture model. An animal model of diabetic-induced fracture was established and the mice were administrated with metformin or glyburide for 3 weeks. Quantitative polymerase chain reaction (qPCR) and Western blotting were used to evaluate the relative expressions of IFN-γ, TNF-α, and IL-6. Micro-computed tomography (μCT) scanning was applied to evaluate bone callus formation. Histopathology examinations of fractured femur sections were performed using Tartrate-resistant acid phosphatase (TRAP) staining and Alcian blue and orange G staining. Bone strength was evaluated using Torsional testing. Our results showed that treatment of glyburide significantly decreased the expressions of IFN-γ, TNF-α, and IL-6 in the fracture calluses in diabetic-induced fracture model, while bone callus volume and bone volume fraction were increased. Additionally, our results also demonstrated that treatment of glyburide rescued the increase of osteoclasts in the bone-cartilage interface. Apart from decreasing a percentage of cartilage area and increasing the percentage of bone and fibrotic tissue area, treatment of glyburide increased the maximum torque and yield torque of fractures. These results implied that glyburide might be used as a potential drug candidate for diabetic-induced fracture.

Inflammasome inhibitors: promising therapeutic approaches against cancer

Inflammation has long been accepted as a key component of carcinogenesis. During inflammation, inflammasomes are potent contributors to the activation of inflammatory cytokines that lead to an inflammatory cascade. Considering the contributing role of inflammasomes in cancer progression, inflammasome inhibitors seem to have a promising future in cancer treatment and prevention. Here, we summarize the structures and signaling pathways of inflammasomes and detail some inflammasome inhibitors used to treat various forms of cancer, which we expect to be used in novel anticancer approaches. However, the practical application of inflammasome inhibitors is limited in regard to specific types of cancer, and the associated clinical trials have not yet been completed. Therefore, additional studies are required to explore more innovative and effective medicines for future clinical treatment of cancer.

Modelling population dynamics and seasonal movement to assess and predict the burden of melioidosis

BACKGROUND

Melioidosis is an infectious disease that is transmitted mainly through contact with contaminated soil or water, and exhibits marked seasonality in most settings, including Southeast Asia. In this study, we used mathematical modelling to examine the impacts of such demographic changes on melioidosis incidence, and to predict the disease burden in a developing country such as Thailand.

METHODOLOGY/PRINCIPAL FINDINGS

A melioidosis infection model was constructed which included demographic data, diabetes mellitus (DM) prevalence, and melioidosis disease processes. The model was fitted to reported melioidosis incidence in Thailand by age, sex, and geographical area, between 2008 and 2015, using a Bayesian Markov Chain Monte Carlo (MCMC) approach. The model was then used to predict the disease burden and future trends of melioidosis incidence in Thailand. Our model predicted two-fold higher incidence rates of melioidosis compared with national surveillance data from 2015. The estimated incidence rates among males were two-fold greater than those in females. Furthermore, the melioidosis incidence rates in the Northeast region population, and among the transient population, were more than double compared to the non-Northeast region population. The highest incidence rates occurred in males aged 45-59 years old for all regions. The average incidence rate of melioidosis between 2005 and 2035 was predicted to be 11.42 to 12.78 per 100,000 population per year, with a slightly increasing trend. Overall, it was estimated that about half of all cases of melioidosis were symptomatic. In addition, the model suggested a greater susceptibility to melioidosis in diabetic compared with non-diabetic individuals.

CONCLUSIONS/SIGNIFICANCE

The increasing trend of melioidosis incidence rates was significantly higher among working-age Northeast and transient populations, males aged ≥45 years old, and diabetic individuals. Targeted intervention strategies, such as health education and awareness raising initiatives, should be implemented on high-risk groups, such as those living in the Northeast region, and the seasonally transient population.

Glibenclamide ameliorates the disrupted blood-brain barrier in experimental intracerebral hemorrhage by inhibiting the activation of NLRP3 inflammasome

BACKGROUND

Glibenclamide is a widely used sulfonylurea drug prescribed to treat type II diabetes mellitus. Previous studies have demonstrated that glibenclamide has neuroprotective effects in central nervous system injury. However, the exact mechanism by which glibenclamide acts on the blood-brain barrier (BBB) after intracerebral hemorrhage (ICH) remains unclear. The purpose of this study was to validate the neuroprotective effects of glibenclamide on ICH and to explore the mechanisms underlying these effects.

METHODS

We investigated the effects of glibenclamide on experimental ICH using the autologous blood infusion model. Glibenclamide was administrated either immediately or 2 hr after ICH. Brain edema was quantified using the wet-dry method 3 days after injury. BBB integrity was evaluated by Evans Blue extravasation and degradation of the tight junction protein zona occludens-1 (ZO-1). mRNA levels of inflammatory cytokines were determined by quantitative polymerase chain reaction. Activation of the nucleotide-binding oligomerization domain-like receptor with a pyrin domain 3 (NLRP3) inflammasome and cell viability were also measured in cerebral microvascular endothelial b.End3 cells exposed to hemin. Neurological changes were evaluated by the Garcia score and rotarod test.

RESULTS

After ICH, the brain water content, Evans Blue extravasation, and inflammatory cytokines decreased significantly in the ipsilateral hemisphere of the experimental compared to the vehicle group. Glibenclamide treatment and NLRP3 knockdown significantly reduced hemin-induced activation of the NLRP3 inflammasome, release of extracellular lactate dehydrogenase, apoptosis, and loss of ZO-1 in b.End3 cells. However, NLRP3 knockdown abolished the protective effect of glibenclamide.

CONCLUSION

Glibenclamide maintained BBB integrity in experimental ICH by inhibiting the activation of the NLRP3 inflammasome in microvessel endothelial cells. Our findings will contribute to elucidating the pharmacological mechanism of action of glibenclamide and to developing a novel therapy for clinical ICH.

Using human experience to identify drug repurposing opportunities: theory and practice

Retrospective evidence drawn from real-world experience of a medicine's use outside its labelled indication is one of a number of techniques used in drug repurposing (DRP). Relying as it does on large numbers of real incidences of human experience, rather than individual case reports with limited statistical support, preclinical experiments with poor translatability or in silico associations, which are early-stage hypotheses, it represents the best validated form of DRP. Cancer is the most frequent of such DRP examples (e.g. aspirin in pancreatic cancer, hazard ratio = 0.25). This approach can be combined with pathway analysis to provide first-in-class treatments for complex diseases. Alternatively, it can be combined with prospective preclinical studies to uncover a validated mechanism for a new indication, after which a repurposed molecule is chemically optimized.

The treatment of melioidosis: is there a role for repurposed drugs? A proposal and review

Introduction: Melioidosis is a significant health problem within endemic areas such as Southeast Asia and Northern Australia. The varied presentation of melioidosis and the intrinsic antibiotic resistance of Burkholderia pseudomallei, the causative organism, make melioidosis a difficult infection to manage. Often prolonged courses of antibiotic treatments are required with no guarantee of clinical success.Areas covered: B. pseudomallei is able to enter phagocytic cells, affect immune function, and replicate, via manipulation of the caspase system. An examination of this mechanism, and a look at other factors in the pathogenesis of melioidosis, shows that there are multiple potential points of therapeutic intervention, some of which may be complementary. These include the directed use of antimicrobial compounds, blocking virulence mechanisms, balancing or modulating cytokine responses, and ameliorating sepsis.Expert commentary: There may be therapeutic options derived from drugs in clinical use for unrelated conditions that may have benefit in melioidosis. Key compounds of interest primarily affect the disequilibrium of the cytokine response, and further preclinical work is needed to explore the utility of this approach and encourage the clinical research needed to bring these into beneficial use.

Antibodies in Melioidosis: The Role of the Indirect Hemagglutination Assay in Evaluating Patients and Exposed Populations

Melioidosis is a major neglected tropical disease with high mortality, caused by the Gram-negative bacterium Burkholderia pseudomallei (Bp). Microbiological culture remains the gold standard for diagnosis, but a simpler and more readily available test such as an antibody assay is highly desirable. In this study, we conducted a serological survey of blood donors (n = 1,060) and adult melioidosis patients (n = 200) in northeast Thailand to measure the antibody response to Bp using the indirect hemagglutination assay (IHA). We found that 38% of healthy adults (aged 17-59 years) have seropositivity (IHA titer ≥ 1:80). The seropositivity in healthy blood donors was associated with having a declared occupation of rice farmer and with residence in a nonurban area, but not with gender or age. In the melioidosis cohort, the seropositivity rate was higher in adult patients aged between 18 and 45 years (90%, 37/41) compared with those aged ≥ 45 years (68%, 108/159, P = 0.004). The seropositivity rate was significantly higher in people with diabetes (P = 0.008). Seropositivity was associated with decreased mortality on univariable analysis (P = 0.005), but not on multivariable analysis when adjusted for age, diabetes status, preexisting renal disease, and neutrophil count. This study confirms the presence of high background antibodies in an endemic region and demonstrates the limitations of using IHA during acute melioidosis in this population.

Hyperglycaemia is inversely correlated with live M. bovis BCG-specific CD4+ T cell responses in Tanzanian adults with latent or active tuberculosis

Introduction

The rising prevalence of Diabetes mellitus (DM) in high TB‐endemic countries may adversely affect sustainability of TB control since DM constitutes a risk factor for development of active tuberculosis (TB). The impact of DM on TB specific adaptive immune responses remains poorly addressed, particularly in people living in Sub‐Saharan countries. We performed a functional characterization of TB specific cellular immune response in Tanzanian subjects with active or latent Mycobacterium tuberculosis (Mtb) infection stratified by their diabetic status.

Methods

HIV negative active TB patients (≥18 years) with Xpert MTB/RIF positive pulmonary TB were included before starting TB treatment in Dar es Salaam, Tanzania between April and December 2013. HIV negative healthy controls latently infected with TB but without past TB history were also included. Active and latent TB patients were stratified in two groups according to their diabetic status. Peripheral Blood Mononuclear cells were stimulated with either live M. bovis BCG or Mtb‐specific peptide pools and analyzed by intracellular cytokine staining and polychromatic flow cytometry.

Results

Our results show a lower frequency of IFN‐γ CD4⁺ T cells in patients with active TB and DM compared to patients with active TB only after live M. bovis BCG (p = 0.04) but not after Mtb peptide pools re‐stimulation. Irrespective of TB status, level of glycaemia is selectively inversely correlated with IFN‐γ and TNF‐α CD4⁺ T cell production (p = 0.02 and p = 0.03) after live M. bovis BCG stimulation.

Conclusions

These results support the hypothesis that hyperglycaemia negatively impacts antigen processing and/or presentation of whole mycobacteria delaying secretion of key cytokines involved in TB immunity.

Oxidative Stress and NLRP3-Inflammasome Activity as Significant Drivers of Diabetic Cardiovascular Complications: Therapeutic Implications

It is now increasingly appreciated that inflammation is not limited to the control of pathogens by the host, but rather that sterile inflammation which occurs in the absence of viral or bacterial pathogens, accompanies numerous disease states, none more so than the complications that arise as a result of hyperglycaemia. Individuals with type 1 or type 2 diabetes mellitus (T1D, T2D) are at increased risk of developing cardiac and vascular complications. Glucose and blood pressure lowering therapies have not stopped the advance of these morbidities that often lead to fatal heart attacks and/or stroke. A unifying mechanism of hyperglycemia-induced cellular damage was initially proposed to link elevated blood glucose levels with oxidative stress and the dysregulation of metabolic pathways. Pre-clinical evidence has, in most cases, supported this notion. However, therapeutic strategies to lessen oxidative stress in clinical trials has not proved efficacious, most likely due to indiscriminate targeting by antioxidants such as vitamins. Recent evidence now suggests that oxidative stress is a major driver of inflammation and vice versa, with the latest findings suggesting not only a key role for inflammatory pathways underpinning metabolic and haemodynamic dysfunction in diabetes, but furthermore that these perturbations are driven by activation of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome. This review will address these latest findings with an aim of highlighting the interconnectivity between oxidative stress, NLRP3 activation and inflammation as it pertains to cardiac and vascular injury sustained by diabetes. Current therapeutic strategies to lessen both oxidative stress and inflammation will be emphasized. This will be placed in the context of improving the burden of these diabetic complications.

Melioidosis

Burkholderia pseudomallei is a Gram-negative environmental bacterium and the aetiological agent of melioidosis, a life-threatening infection that is estimated to account for ∼89,000 deaths per year worldwide. Diabetes mellitus is a major risk factor for melioidosis, and the global diabetes pandemic could increase the number of fatalities caused by melioidosis. Melioidosis is endemic across tropical areas, especially in southeast Asia and northern Australia. Disease manifestations can range from acute septicaemia to chronic infection, as the facultative intracellular lifestyle and virulence factors of B. pseudomallei promote survival and persistence of the pathogen within a broad range of cells, and the bacteria can manipulate the host's immune responses and signalling pathways to escape surveillance. The majority of patients present with sepsis, but specific clinical presentations and their severity vary depending on the route of bacterial entry (skin penetration, inhalation or ingestion), host immune function and bacterial strain and load. Diagnosis is based on clinical and epidemiological features as well as bacterial culture. Treatment requires long-term intravenous and oral antibiotic courses. Delays in treatment due to difficulties in clinical recognition and laboratory diagnosis often lead to poor outcomes and mortality can exceed 40% in some regions. Research into B. pseudomallei is increasing, owing to the biothreat potential of this pathogen and increasing awareness of the disease and its burden; however, better diagnostic tests are needed to improve early confirmation of diagnosis, which would enable better therapeutic efficacy and survival.

Mitigating the Impact of Antibacterial Drug Resistance through Host-Directed Therapies: Current Progress, Outlook, and Challenges

Increasing incidences of multidrug resistance in pathogenic bacteria threaten our ability to treat and manage bacterial infection. The development and FDA approval of novel antibiotics have slowed over the past decade; therefore, the adoption and improvement of alternative therapeutic strategies are critical for addressing the threat posed by multidrug-resistant bacteria. Host-directed therapies utilize small-molecule drugs and proteins to alter the host response to pathogen infection. Here, we highlight strategies for modulating the host inflammatory response to enhance bacterial clearance, small-molecule potentiation of innate immunity, and targeting of host factors that are exploited by pathogen virulence factors. Application of state-of-the-art "omic" technologies, including proteomics, transcriptomics, and image-omics (image-based high-throughput phenotypic screening), combined with powerful bioinformatics tools will enable the modeling of key signaling pathways in the host-pathogen interplay and aid in the identification of host proteins for therapeutic targeting and the discovery of host-directed small molecules that will regulate bacterial infection. We conclude with an outlook on research needed to overcome the challenges associated with transitioning host-directed therapies into a clinical setting.

Therapeutic Administration of a Monoclonal Anti-Il-1β Antibody Protects Against Experimental Melioidosis

BACKGROUND

Melioidosis, caused by the gram-negative bacterium Burkholderia pseudomallei, is a common cause of community-acquired sepsis in Southeast Asia and Northern Australia. The NLRP3 inflammasome and its downstream product interleukin-1 beta (IL-1β) have been proposed to play crucial roles in melioidosis. In this study, we characterized the role of IL-1β more closely and we assessed its therapeutic potential.

METHODS

mRNA expression of inflammasome components was determined in isolated leukocytes of 32 healthy controls and 34 patients with sepsis caused by B pseudomallei.Wild-type (WT), NLRP3-deficient (Nlrp3), and Asc mice were infected with B pseudomallei. In additional experiments, infected WT mice were treated with an anti-IL-1β antibody. After 24, 48, and 72 hours (h) mice were sacrificed and organs were harvested. Furthermore, survival studies were performed.

RESULTS

Patients with melioidosis exhibited lower mRNA levels of caspase-1, NLRP3, and ASC. Bacterial dissemination and organ damage were increased in B pseudomallei-infected Nlrp3 and Asc mice, together with a reduced pulmonary cell influx. Anti-IL-1β treatment of B pseudomallei challenged mice resulted in strongly reduced bacterial counts, organ damage, and pulmonary granulocyte influx together with reduced mortality. Postponement of anti-IL-1β treatment for 24 h postinfection still protected mice during melioidosis.

CONCLUSION

Expression of caspase-1, NLRP3, and ASC is altered in melioidosis patients. In mice, both NLRP3 and ASC contribute to the host defense against melioidosis. Anti-IL-1β treatment protects mice against B pseudomallei infection and might be a novel treatment strategy in melioidosis.

Glyburide and retinoic acid synergize to promote wound healing by anti-inflammation and RIP140 degradation

Chronic inflammation underlies the development of metabolic diseases and individuals with metabolic disease often also suffer from delayed wound healing due to prolonged inflammation. Resolving inflammation provides a therapeutic strategy in treating metabolic diseases. We previously showed that during an anti-inflammatory response when macrophages were alternatively (M2) polarized, retinoic acid (RA) dramatically activated arginase 1 gene (Arg1), a gene crucial for wound healing. Here we report that a widely used sulfonylurea drug for type 2 diabetes mellitus (T2DM), glyburide, enhances the anti-inflammatory response and synergizes with RA to promote wound healing. Our data also delineate the mechanism underlying glyburide’s anti-inflammatory effect, which is to stimulate the degradation of a pro-inflammatory regulator, Receptor Interacting Protein 140 (RIP140), by activating Ca2+/calmodulin-dependent protein kinase II (CamKII) that triggers specific ubiquitination of RIP140 for degradation. By stimulating RIP140 degradation, glyburide enhances M2 polarization and anti-inflammation. Using a high-fat diet induced obesity mouse model to monitor wound healing effects, we provide a proof-of-concept for a therapeutic strategy that combining glyburide and RA can significantly improve wound healing. Mechanistically, this study uncovers a new mechanism of action of glyburide and a new pathway modulating RIP140 protein degradation that is mediated by CamKII signaling.

Inhibiting Inflammasomes with Small Molecules

Modulation of inflammasomes has tremendous therapeutic potential and is hotly pursued by industry and academia alike. Indeed a growing number of patents are emerging to protect the intellectual property in valuable compound classes. This chapter focusses specifically on the suite of small-molecule NLRP3 inflammasome inhibitors published, as specific modulation of other inflammasomes is not yet well established. Synthetic molecules, known drugs and natural product NLRP3 modulators will be detailed. Some of the molecular classes discussed have been extensively characterised through cell-based screening, pharmacokinetic profiling and therapeutic proof of concept animal models. However, many inhibitors lack rigorous studies and/or have multiple activities of which NLRP3 modulation is only one. While this is not intended as an exhaustive list, it should give an impression of the range of structures and strategies that are being used, alongside challenges encountered, in an effort to exploit the significant therapeutic benefits of targeting inflammasomes.

Diabetes does not influence activation of coagulation, fibrinolysis or anticoagulant pathways in Gram-negative sepsis (melioidosis)

Diabetes is associated with a disturbance of the haemostatic balance and is an important risk factor for sepsis, but the influence of diabetes on the pathogenesis of sepsis remains unclear. Melioidosis (Burkholderia pseudomallei infection) is a common cause of community-acquired sepsis in Southeast Asia and northern Australia. We sought to investigate the impact of pre-existing diabetes on the coagulation and fibrinolytic systems during sepsis caused by B. pseudomallei. We recruited a cohort of 44 patients (34 with diabetes and 10 without diabetes) with culture-proven melioidosis. Diabetes was defined as a pre-admission diagnosis of diabetes or an HbA1c>7.8% at enrolment. Thirty healthy blood donors and 52 otherwise healthy diabetes patients served as controls. Citrated plasma was collected from all subjects; additionally in melioidosis patients follow-up specimens were collected seven and ≥28 days after enrolment where possible. Relative to uninfected healthy controls, diabetes per se (i.e. in the absence of infection) was Characterised by a procoagulant effect. Melioidosis was associated with activation of coagulation (thrombin-antithrombin complexes (TAT), prothrombin fragment F1+2 and fibrinogen concentrations were elevated; PT and PTT prolonged), suppression of anti-coagulation (antithrombin, protein C, total and free protein S levels were depressed) and abnormalities of fibrinolysis (D-dimer and plasmin-antiplasmin complex [PAP] were elevated). Remarkably, none of these haemostatic alterations were influenced by pre-existing diabetes. In conclusion, although diabetes is associated with multiple abnormalities of coagulation, anticoagulation and fibrinolysis, these changes are not detectable when superimposed on the background of larger abnormalities attributable to B. pseudomallei sepsis.

A Protective Role of Glibenclamide in Inflammation-Associated Injury

Glibenclamide is the most widely used sulfonylurea drug for the treatment of type 2 diabetes mellitus (DM). Recent studies have suggested that glibenclamide reduced adverse neuroinflammation and improved behavioral outcomes following central nervous system (CNS) injury. We reviewed glibenclamide's anti-inflammatory effects: abundant evidences have shown that glibenclamide exerted an anti-inflammatory effect in respiratory, digestive, urological, cardiological, and CNS diseases, as well as in ischemia-reperfusion injury. Glibenclamide might block K_ATP channel, Sur1-Trpm4 channel, and NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome activation, decrease the production of proinflammatory mediators (TNF-α, IL-1β, and reactive oxygen species), and suppress the accumulation of inflammatory cells. Glibenclamide's anti-inflammation warrants further investigation.

The global diabetes epidemic: what does it mean for infectious diseases in tropical countries?

Tropical countries are experiencing a substantial rise in type 2 diabetes, which is often undiagnosed or poorly controlled. Since diabetes is a risk factor for many infectious diseases, this increase probably adds to the large infectious disease burden in tropical countries. We reviewed the literature to investigate the interface between diabetes and infections in tropical countries, including the WHO-defined neglected tropical diseases. Although solid data are sparse, patients with diabetes living in tropical countries most likely face increased risks of common and health-care-associated infections, as well as infected foot ulcers, which often lead to amputation. There is strong evidence that diabetes increases the severity of some endemic infections such as tuberculosis, melioidosis, and dengue virus infection. Some HIV and antiparasitic drugs might induce diabetes, whereas helminth infections appear to afford some protection against future diabetes. But there are no or very scarce data for most tropical infections and for possible biological mechanisms underlying associations with diabetes. The rise in diabetes and other non-communicable diseases puts a heavy toll on health systems in tropical countries. On the other hand, complications common to both diabetes and some tropical infections might provide an opportunity for shared services-for example, for eye health (trachoma and onchocerciasis), ulcer care (leprosy), or renal support (schistosomiasis). More research about the interaction of diabetes and infections in tropical countries is needed, and the infectious disease burden in these countries is another reason to step up global efforts to improve prevention and care for diabetes.

Interleukin 10 inhibits pro-inflammatory cytokine responses and killing of Burkholderia pseudomallei

Melioidosis, caused by Burkholderia pseudomallei, is endemic in northeastern Thailand and Northern Australia. Severe septicemic melioidosis is associated with high levels of pro-inflammatory cytokines and is correlated with poor clinical outcomes. IL-10 is an immunoregulatory cytokine, which in other infections can control the expression of pro-inflammatory cytokines, but its role in melioidosis has not been addressed. Here, whole blood of healthy seropositive individuals (n = 75), living in N. E. Thailand was co-cultured with B. pseudomallei and production of IL-10 and IFN-γ detected and the cellular sources identified. CD3⁻ CD14⁺ monocytes were the main source of IL-10. Neutralization of IL-10 increased IFN-γ, IL-6 and TNF-α production and improved bacteria killing. IFN-γ production and microbicidal activity were impaired in individuals with diabetes mellitus (DM). In contrast, IL-10 production was unimpaired in individuals with DM, resulting in an IL-10 dominant cytokine balance. Neutralization of IL-10 restored the IFN-γ response of individuals with DM to similar levels observed in healthy individuals and improved killing of B. pseudomallei in vitro. These results demonstrate that monocyte derived IL-10 acts to inhibit potentially protective cell mediated immune responses against B. pseudomallei, but may also moderate the pathological effects of excessive cytokine production during sepsis.

Glibenclamide Prevents Diabetes in NOD Mice

Previous work has revealed that Cx36, the sole connexin expressed in the insulin-producing beta cells, enhances the secretion of insulin, and promotes the resistance of beta cells against pro-inflammatory cytokines. In parallel, the anti-diabetic sulphonylurea glibenclamide was shown to promote the assembly and function of Cx36 channels. Here, we assessed whether glibenclamide could protect the insulin-producing cells against conditions mimicking those expected at the onset of type 1 diabetes. We found that the drug 1) protected in vitro the mouse MIN6 cells from the apoptosis and loss of Cx36, which are induced by Th1 cytokines; 2) prevented the development of hyperglycemia as well as the loss of beta cells and Cx36, which rapidly develop with aging in untreated NOD mice; 3) modified the proportion of effector CD4⁺ and CD8⁺ T cells in pancreatic draining lymph nodes. The data imply that an early glibenclamide treatment may help protecting beta cells against the autoimmune attack, which triggers the development of type 1 diabetes.

Glibenclamide impairs responses of neutrophils against Burkholderia pseudomallei by reduction of intracellular glutathione

The major risk factor for melioidosis, an infectious disease caused by B. pseudomallei, is diabetes mellitus. More than half of diabetic melioidosis patients in Thailand were prescribed glibenclamide. Recent evidence demonstrates that glibenclamide reduces pro-inflammatory cytokine production by polymorphonuclear neutrophils (PMNs) of diabetic individuals in response to this bacterial infection. However, the mechanisms by which glibenclamide affects cytokine production are unknown. We found that PMNs from glibenclamide-treated diabetic individuals infected with live B. pseudomallei in vitro showed lower free glutathione (GSH) levels compared with those of healthy individuals. Glibenclamide decreased GSH levels and glutathione peroxidase (GPx) of PMNs after exposed to live B. pseudomallei. Moreover, glibenclamide reduced cytokine production and migration capacity of infected PMNs, whereas GSH could restore these functions. Taken together, our data show a link between the effect of glibenclamide on GSH and PMN functions in response to B. pseudomallei that may contribute to the susceptibility of diabetic individuals to B. pseudomallei infection.

Host-directed therapies for infectious diseases: current status, recent progress, and future prospects

Despite extensive global efforts in the fight against killer infectious diseases, they still cause one in four deaths worldwide and are important causes of long-term functional disability arising from tissue damage. The continuing epidemics of tuberculosis, HIV, malaria, and influenza, and the emergence of novel zoonotic pathogens represent major clinical management challenges worldwide. Newer approaches to improving treatment outcomes are needed to reduce the high morbidity and mortality caused by infectious diseases. Recent insights into pathogen–host interactions, pathogenesis, inflammatory pathways, and the host's innate and acquired immune responses are leading to identification and development of a wide range of host-directed therapies with different mechanisms of action. Host-directed therapeutic strategies are now becoming viable adjuncts to standard antimicrobial treatment. Host-directed therapies include commonly used drugs for non-communicable diseases with good safety profiles, immunomodulatory agents, biologics (eg monoclonal antibodies), nutritional products, and cellular therapy using the patient's own immune or bone marrow mesenchymal stromal cells. We discuss clinically relevant examples of progress in identifying host-directed therapies as adjunct treatment options for bacterial, viral, and parasitic infectious diseases.

Metformin and other glucose-lowering drug initiation and rates of community-based antibiotic use and hospital-treated infections in patients with type 2 diabetes: a Danish nationwide population-based cohort study

OBJECTIVE

Data on early risk of infection in patients receiving their first treatment for type 2 diabetes are limited. We examined rates of community-based antibiotic use and hospital-treated infection in initiators of metformin and other glucose-lowering drugs (GLDs).

DESIGN

Population-based cohort study using medical databases.

SETTING

General practice and hospitals in Denmark.

PARTICIPANTS

131 949 patients with type 2 diabetes who initiated pharmacotherapy with a GLD between 2005 and 2012.

EXPOSURE

Initial GLD used for pharmacotherapy.

MAIN OUTCOME MEASURES

We computed rates and adjusted HRs of community-based antibiotic use and hospital-treated infection associated with choice of initial GLD with reference to metformin initiation, using an intention-to-treat approach.

RESULTS

The rate of community-based antibiotic use was 362 per 1000 patient-years at risk (PYAR) and that for hospital-treated infection was 51 per 1000 PYAR. Compared with metformin, the risk of hospital-treated infection was slightly higher in sulfonylurea initiators (HR 1.12, 95% CI 1.08 to 1.16) and substantially higher in insulin initiators (HR 1.63, 95% CI 1.54 to 1.72) initiators after adjustment for comorbid conditions, comedications and other confounding factors. In contrast, virtually no difference was observed for overall community-based antibiotic use (HR 1.02, 95% CI 1.01 to 1.04, for sulfonylurea initiators; and 1.04, 95% CI 1.01 to 1.07, for insulin initiators).

CONCLUSIONS

Rates of community-based antibiotic treatment and hospitalisation for infection were high in patients receiving their first treatment for type 2 diabetes and differed with the choice of initial GLD used for pharmacotherapy.

Short-Term High-Fat Diet (HFD) Induced Anxiety-Like Behaviors and Cognitive Impairment Are Improved with Treatment by Glyburide

Obesity-associated comorbidities such as cognitive impairment and anxiety are increasing public health burdens that have gained prevalence in children. To better understand the impact of childhood obesity on brain function, mice were fed with a high-fat diet (HFD) from weaning for 1, 3 or 6 weeks. When compared to low-fat diet (LFD)-fed mice (LFD-mice), HFD-fed mice (HFD-mice) had impaired novel object recognition (NOR) after 1 week. After 3 weeks, HFD-mice had impaired NOR and object location recognition (OLR). Additionally, these mice displayed anxiety-like behavior by measure of both the open-field and elevated zero maze (EZM) testing. At 6 weeks, HFD-mice were comparable to LFD-mice in NOR, open-field and EZM performance but they remained impaired during OLR testing. Glyburide, a second-generation sulfonylurea for the treatment of type 2 diabetes, was chosen as a countermeasure based on previous data exhibiting its potential as an anxiolytic. Interestingly, a single dose of glyburide corrected deficiencies in NOR and mitigated anxiety-like behaviors in mice fed with HFD-diet for 3-weeks. Taken together these results indicate that a HFD negatively impacts a subset of hippocampal-independent behaviors relatively rapidly, but such behaviors normalize with age. In contrast, impairment of hippocampal-sensitive memory takes longer to develop but persists. Since single-dose glyburide restores brain function in 3-week-old HFD-mice, drugs that block ATP-sensitive K(+) (KATP) channels may be of clinical relevance in the treatment of obesity-associated childhood cognitive issues and psychopathologies.

Bioelectric modulation of macrophage polarization

Macrophages play a critical role in regulating wound healing and tissue regeneration by changing their polarization state in response to local microenvironmental stimuli. The native roles of polarized macrophages encompass biomaterials and tissue remodeling needs, yet harnessing or directing the polarization response has been largely absent as a potential strategy to exploit in regenerative medicine to date. Recent data have revealed that specific alteration of cells' resting potential (Vmem) is a powerful tool to direct proliferation and differentiation in a number of complex tissues, such as limb regeneration, craniofacial patterning and tumorigenesis. In this study, we explored the bioelectric modulation of macrophage polarization by targeting ATP sensitive potassium channels (KATP). Glibenclamide (KATP blocker) and pinacidil (KATP opener) treatment not only affect macrophage polarization, but also influence the phenotype of prepolarized macrophages. Furthermore, modulation of cell membrane electrical properties can fine-tune macrophage plasticity. Glibenclamide decreased the secretion and gene expression of selected M1 markers, while pinacidil augmented M1 markers. More interestingly, glibencalmide promoted macrophage alternative activation by enhancing certain M2 markers during M2 polarization. These findings suggest that control of bioelectric properties of macrophages could offer a promising approach to regulate macrophage phenotype as a useful tool in regenerative medicine.

Role of Canonical and Non-canonical Inflammasomes During Burkholderia Infection

Burkholderia pseudomallei is a Gram-negative flagellate bacterium that causes melioidosis, a disease endemic to Southeast Asia and other tropical regions. Following infection of macrophages and other non-phagocytic cell types, B. pseudomallei or B. thailandensis (a related species that causes disease in mice but not humans) are able to escape the phagosome and replicate in the host cell cytoplasm. Resistance to infection with Burkholderia is dependent on the Nlrp3 and Nlrc4 inflammasomes and the non-canonical caspase-11 inflammasome. Nlrc4 mediates protection through induction of pyroptosis in the early phase of infection. As the infection progresses and as IL-18-dependent IFNγ production increases, caspase-11-dependent pyroptosis acquires a preponderant protective role. Production of IL-1β and IL-18 during infection is primarily mediated by Nlrp3. IL-18 is essential for survival because of its ability to induce IFNγ production, which in turn activates macrophage microbicidal functions and primes for caspase-11 expression. In contrast, during melioidosis, IL-1β has deleterious effects due to excessive recruitment of neutrophils to the lung and consequent tissue damage.