Reduced immune cell infiltration and increased pro-inflammatory mediators in the brain of Type 2 diabetic mouse model infected with West Nile virus

Viral infection and host immune response in diabetes

Diabetes, a chronic metabolic disorder disrupting blood sugar regulation, has emerged as a prominent silent pandemic. Uncontrolled diabetes predisposes an individual to develop fatal complications like cardiovascular disorders, kidney damage, and neuropathies and aggravates the severity of treatable infections. Escalating cases of Type 1 and Type 2 diabetes correlate with a global upswing in diabetes-linked mortality. As a growing global concern with limited preventive interventions, diabetes necessitates extensive research to mitigate its healthcare burden and assist ailing patients. An altered immune system exacerbated by chronic hyperinflammation heightens the susceptibility of diabetic individuals to microbial infections, including notable viruses like SARS-CoV-2, dengue, and influenza. Given such a scenario, we scrutinized the literature and compiled molecular pathways and signaling cascades related to immune compartments in diabetics that escalate the severity associated with the above-mentioned viral infections in them as compared to healthy individuals. The pathogenesis of these viral infections that trigger diabetes compromises both innate and adaptive immune functions and pre-existing diabetes also leads to heightened disease severity. Lastly, this review succinctly outlines available treatments for diabetics, which may hold promise as preventive or supportive measures to effectively combat these viral infections in the former.

Diabetes mellitus as a risk factor for severe dengue fever and West Nile fever: A meta-analysis

BACKGROUND

Dengue fever (DF) and West Nile fever (WNF) have become endemic worldwide in the last two decades. Studies suggest that individuals with diabetes mellitus (DM) are at a higher risk of developing severe complications from these diseases. Identifying the factors associated with a severe clinical presentation is crucial, as prompt treatment is essential to prevent complications and fatalities. This article aims to summarize and assess the published evidence regarding the link between DM and the risk of severe clinical manifestations in cases of DF and WNF.

METHODOLOGY/PRINCIPAL FINDINGS

A systematic search was conducted using the PubMed and Web of Science databases. 27 studies (19 on DF, 8 on WNF) involving 342,873 laboratory-confirmed patients were included in the analysis. The analysis showed that a diagnosis of DM was associated with an increased risk for severe clinical presentations of both DF (OR 3.39; 95% CI: 2.46, 4.68) and WNF (OR 2.89; 95% CI: 1.89, 4.41). DM also significantly increased the risk of death from both diseases (DF: OR 1.95; 95% CI: 1.09, 3.52; WNF: OR 1.74; 95% CI: 1.40, 2.17).

CONCLUSIONS/SIGNIFICANCE

This study provides strong evidence supporting the association between DM and an increased risk of severe clinical manifestations in cases of DF and WNF. Diabetic individuals in DF or WNF endemic areas should be closely monitored when presenting with febrile symptoms due to their higher susceptibility to severe disease. Early detection and appropriate management strategies are crucial in reducing the morbidity and mortality rates associated with DF and WNF in diabetic patients. Tailored care and targeted public health interventions are needed to address this at-risk population. Further research is required to understand the underlying mechanisms and develop effective preventive and therapeutic approaches.

Immunomodulation through Nutrition Should Be a Key Trend in Type 2 Diabetes Treatment

An organism's ability to function properly depends not solely on its diet but also on the intake of nutrients and non-nutritive bioactive compounds that exert immunomodulatory effects. This principle applies both to healthy individuals and, in particular, to those with concomitant chronic conditions, such as type 2 diabetes. However, the current food industry and the widespread use of highly processed foods often lead to nutritional deficiencies. Numerous studies have confirmed the occurrence of immune system dysfunction in patients with type 2 diabetes. This article elucidates the impact of specific nutrients on the immune system function, which maintains homeostasis of the organism, with a particular emphasis on type 2 diabetes. The role of macronutrients, micronutrients, vitamins, and selected substances, such as omega-3 fatty acids, coenzyme Q10, and alpha-lipoic acid, was taken into consideration, which outlined the minimum range of tests that ought to be performed on patients in order to either directly or indirectly determine the severity of malnutrition in this group of patients.

Inflammatory Response Associated with West Nile Neuroinvasive Disease: A Systematic Review

BACKGROUND

West Nile virus (WNV) infection is a seasonal arbovirosis with the potential to cause severe neurological disease. Outcomes of the infection from WNV depend on viral factors (e.g., lineage) and host-intrinsic factors (e.g., age, sex, immunocompromising conditions). Immunity is essential to control the infection but may also prove detrimental to the host. Indeed, the persistence of high levels of pro-inflammatory cytokines and chemokines is associated with the development of blood-brain barrier (BBB) damage. Due to the importance of the inflammatory processes in the development of West Nile neuroinvasive disease (WNND), we reviewed the available literature on the subject.

METHODS

According to the 2020 updated PRISMA guidelines, all peer-reviewed articles regarding the inflammatory response associated with WNND were included.

RESULTS

One hundred and thirty-six articles were included in the data analysis and sorted into three groups (in vitro on-cell cultures, in vivo in animals, and in humans). The main cytokines found to be increased during WNND were IL-6 and TNF-α. We highlighted the generally small quantity and heterogeneity of information about the inflammatory patterns associated with WNND.

CONCLUSIONS

Further studies are needed to understand the pathogenesis of WNND and to investigate the extent and the way the host inflammatory response either helps in controlling the infection or in worsening the outcomes. This might prove useful both for the development of target therapies and for the development of molecular markers allowing early identification of patients displaying an inflammatory response that puts them at a higher risk of developing neuroinvasive disease and who might thus benefit from early antiviral therapies.

The Influence of Metabolism on Immune Response: A Journey to Understand Immunometabolism in the Context of Viral Infection

In recent years, the emergence of the concept of immunometabolism has shed light on the pivotal role that cellular metabolism plays in both the activation of immune cells and the development of immune programs. The antiviral response, a widely distributed defense mechanism used by infected cells, serves to not only control infections but also to attenuate their deleterious effects. The exploration of the role of metabolism in orchestrating the antiviral response represents a burgeoning area of research, especially considering the escalating incidence of viral outbreaks coupled with the increasing prevalence of metabolic diseases. Here, we present a review of current knowledge regarding immunometabolism and the antiviral response during viral infections. Initially, we delve into the concept of immunometabolism by examining its application in the field of cancer-a domain that has long spearheaded inquiries into this fascinating intersection of disciplines. Subsequently, we explore examples of immune cells whose activation is intricately regulated by metabolic processes. Progressing with a systematic and cellular approach, our aim is to unravel the potential role of metabolism in antiviral defense, placing significant emphasis on the innate and canonical interferon response.

Lower odds of COVID-19-related mortality in hospitalised patients with type II diabetes mellitus: A single-centre study

BACKGROUND

COVID-19 infection in patients with type 2 diabetes mellitus (T2DM) -a chronic illness in Lebanon-is not well described.

METHODS

This was a single-centre retrospective observational study of 491 patients, including 152 patients with T2DM, who were hospitalised for COVID-19 between 20 August 2020 and 21 April 2021. Data on clinical characteristics, laboratory and radiological findings and outcomes were collected from the electronic medical records. Clinical characteristics and in-hospital mortality between patients with and without T2DM infected with COVID-19 using multivariate analysis were compared.

RESULTS

Patients with T2DM were significantly older than those without T2DM (mean age, 68.7 vs. 60.3 years). Patients with T2DM were more likely to present with a body temperature of <38.3°C (83.9% vs. 69.9%) and less likely to present with chest pain (3.9% vs. 9.1%) and sore throat (2.0% vs. 6.8%). Patients with T2DM were more likely to be hypertensive (76.35% vs. 41%) and dyslipidaemic (58.6% vs. 25.7%) and had more frequent underlying coronary artery disease (33.6% vs. 12.4%). The rates of patients with creatinine levels of ≥1.17 mg/L and troponin T levels of ≥4 ng/dL were higher in the T2DM group than in the non-T2DM group (30.4% vs. 15% and 93.3% vs. 83.1%, respectively). Patients with T2DM were more likely to be admitted to the intensive care unit (ICU) (34.2% vs. 22.1%), require invasive ventilation (18.4% vs. 10.3%) and receive vasopressors (16.4% vs. 10.0%). Increasing age and the use of invasive ventilation and vasopressors were associated with higher odds of mortality (odds ratio (OR), 1.08, 9.95 and 19.83, respectively), whereas longer ICU stay was associated with lower odds of mortality (OR, 0.38). The odds of mortality were lower in the T2DM group than in the non-T2DM group (OR, 0.27).

CONCLUSION

Among patients hospitalised for COVID-19, those with T2DM were older, presented with milder symptoms and had more comorbidities and higher troponin T levels compared with those without T2DM. Despite the worse clinical course, the patients with T2DM had lower odds of mortality than those without T2DM.

PI3K-AKT-mTOR signaling pathway regulates autophagy of hippocampal neurons in diabetic rats with chronic unpredictable mild stress

It is reported that the co-morbidities of diabetes and depression will be a new challenge for humanity. However, the underlying mechanism is not clear. The present study investigated the histopathology, autophagy of hippocampal neurons, and the PI3K-AKT- mTOR signaling pathway in type 2 diabetes with depression（T2DD） rats. The results showed that, the chronic unpredictable mild stress (CUMS), Type 2 diabetes mellitus (T2DM) and T2DD in rats were induced successfully. Compared with the CUMS and T2DM groups, the T2DD group performed significantly fewer autonomic activities in the open-field test, and longer immobile in the force swimming test, and increasing of Corticosterone (CORT) in blood. The number of pyknotic neurons at cornu ammonis 1 (CA1) and dentate gyrus (DG) of the hippocampus in T2DD was significantly increased compared with CUMS and T2DM groups. Moreover, compared with the CUMS and T2DM groups, the mitochondrial autophagosomes were most abundant in the T2DD group. As shown in western blot and immunofluorescence, compared with the control group, in the CUMS, T2DM and T2DD groups, significantly increased expression of Beclin-1 and LC3B and decreased P62 were detected. In the PC12 cells, the relative amount of parkin and LC3B in the CORT+HG group was significantly higher than that in the CORT and HG groups. Compared with the control group, p-AKT/AKT and p-mTOR/mTOR in CUMS, T2DM and T2DD groups were significantly decreased. Compared with the CUMS group, p-AKT/AKT, p-PI3K/PI3K and p-mTOR/mTOR in the T2DD group exhibited further decrease. Similar results were obtained in PC12 cells in vitro. It is suggests that memory and cognitive impairment in rats with co-morbidities of diabetes and depression might be related with hippocampal neuronal damage and autophagy increase, which was involved in the PI3K-AKT-mTOR signaling pathway.

Mast Cell Deficiency in Mice Attenuates Insulin Phenolic Preservative-Induced Inflammation

One major obstacle that limits the lifespan of insulin infusion pumps is surmounting the tissue site reaction at the device implantation site. All commercial insulin formulations contain insulin phenolic preservatives (IPPs) designed to ensure insulin protein stability and prolong shelf-life. However, our laboratory demonstrated that these preservatives are cytotoxic and induce inflammation. Mature mast cells (MCs) reside in cutaneous tissue and are one of the first responders to an epidermal breach. Upon activation, MCs release proinflammatory and immunomodulatory prepacked mediators that exacerbate these inflammatory reactions. Thus, we hypothesized that once the epidermis is breached, cutaneous MCs are triggered inciting the inflammatory response to IPP-induced inflammation. This hypothesis was pursued utilizing our modified in vivo mouse air pouch model, including a c-kit dependent (C57BL/6J-kitW-sh/W-sh) and a c-kit independent (Cpa3-Cre; Mcl-1fl/fl) MC-deficient mouse model. Leukocytes were quantified in the mouse air pouch lavage fluid following flow cytometry analysis for IPP infusion under three different states, insulin-containing phenolic preservatives (Humalog®), insulin preservatives alone, and normal saline as a control. The air pouch wall was assessed using histopathological evaluations. Flow cytometry analysis demonstrated a statistically significant difference in inflammatory cell recruitment for both MC-deficient mouse models when compared to the control strain including infused control saline. Significantly less inflammation was observed at the site of infusion for the MC-deficient strains compared to the control strain. Overall, concordant results were obtained in both mouse types, C57Bl6-kitW-sh/W-sh and Cpa3-Cre; Mcl-1fl/fl. These findings in multiple model systems support the conclusion that MCs have important or possible unique roles in IPP-induced inflammation.

A narrative review: CXC chemokines influence immune surveillance in obesity and obesity-related diseases: Type 2 diabetes and nonalcoholic fatty liver disease

Adipose tissue develops lipids, aberrant adipokines, chemokines, and pro-inflammatory cytokines as a consequence of the low-grade systemic inflammation that characterizes obesity. This low-grade systemic inflammation can lead to insulin resistance (IR) and metabolic complications, such as type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD). Although the CXC chemokines consists of numerous regulators of inflammation, cellular function, and cellular migration, it is still unknown that how CXC chemokines and chemokine receptors contribute to the development of metabolic diseases (such as T2D and NAFLD) during obesity. In light of recent research, the objective of this review is to provide an update on the linkage between the CXC chemokine, obesity, and obesity-related metabolic diseases (T2D and NAFLD). We explore the differential migratory and immunomodulatory potential of CXC chemokines and their mechanisms of action to better understand their role in clinical and laboratory contexts. Besides that, because CXC chemokine profiling is strongly linked to leukocyte recruitment, macrophage recruitment, and immunomodulatory potential, we hypothesize that it could be used to predict the therapeutic potential for obesity and obesity-related diseases (T2D and NAFLD).

Diabetes and climate change: current evidence and implications for people with diabetes, clinicians and policy stakeholders

Climate change will be a major challenge for the world's health systems in the coming decades. Elevated temperatures and increasing frequencies of heat waves, wildfires, heavy precipitation and other weather extremes can affect health in many ways, especially if chronic diseases are already present. Impaired responses to heat stress, including compromised vasodilation and sweating, diabetes-related comorbidities, insulin resistance and chronic low-grade inflammation make people with diabetes particularly vulnerable to environmental risk factors, such as extreme weather events and air pollution. Additionally, multiple pathogens show an increased rate of transmission under conditions of climate change and people with diabetes have an altered immune system, which increases the risk for a worse course of infectious diseases. In this review, we summarise recent studies on the impact of climate-change-associated risk for people with diabetes and discuss which individuals may be specifically prone to these risk conditions due to their clinical features. Knowledge of such high-risk groups will help to develop and implement tailored prevention and management strategies to mitigate the detrimental effect of climate change on the health of people with diabetes.

Insight on Infections in Diabetic Setting

The correlation between diabetes mellitus and infectious diseases is widely recognized. DM patients are characterized by the impaired function of the immune system. This translates into the occurrence of a variety of infections, including urinary tract, skin and surgical site infections, pneumonia, tuberculosis, and, more recently, SARS-CoV-2. Hyperglycemia has been identified as a relevant factor contributing to unfavorable outcomes in hospitalized patients including SARS-CoV-2 patients. Several studies have been performed proving that to maintain the proper and stringent monitoring of glycemia, a balanced diet and physical activity is mandatory to reduce the risk of infections and their associated complications. This review is focused on the mechanisms accounting for the increased susceptibility of DM patients to infections, with particular attention to the impact of newly introduced hypoglycemic drugs in sepsis management.

Influenza Prevalence and Vaccine Efficacy among Diabetic Patients in Qatar

Seasonal influenza viruses may lead to severe illness and mortality in patients with comorbidities, including Diabetes Mellitus (DM). Vaccination against influenza in DM patients may reduce influenza incidence and severity. Before the emergence of the COVID-19 pandemic, influenza infections were the most prevalent respiratory infections in Qatar. Still, reports about influenza prevalence and vaccine efficacy in DM patients have not been reported. This study aimed to analyze influenza prevalence among other respiratory infections and assess influenza vaccine efficacy in DM patients in Qatar. Statistical analysis was performed on data obtained from Hamad Medical Corporation (HMC) database for patients that visited the emergency department (ED) with respiratory-like illnesses. The analysis was done for the period between January 2016 to December 2018. Among 17,525 patients who visited HMC-ED with clinical symptoms of respiratory infections, 2611(14.9%) were reported to have DM. Among DM patients, influenza was the most prevalent respiratory pathogen at 48.9%. Influenza virus A (IVA) was the most circulating type, contributing to 38.4%, followed by IVB contributing to 10.4% of total respiratory infections. Among the typed IVA-positive cases, 33.4% were H1N1, and 7.7% were H3N2. A significant decrease in influenza infections was reported in vaccinated DM patients (14.5%) when compared to non-vaccinated patients (18.9%) (p-value = 0.006). However, there was no significant relaxation in the clinical symptoms among vaccinated DM patients compared to their non-vaccinated counterparts. In conclusion, influenza was the most common etiology for respiratory viral infection among diabetic patients at the leading healthcare provider in Qatar. Although vaccination reduced the incidence rate among DM patients, it was less effective in preventing symptoms. Further studies on a larger cohort and for a more extended period are required to investigate influenza prevalence and vaccine efficacy among DM patients.

Complications of Severe Odontogenic Infections: A Review

Severe odontogenic infections are routinely treated with little associated morbidity and mortality. Improvements in surgical techniques, antibiotic treatments, and imaging modalities have made associated complications exceedingly rare. A number of complications have been described in the literature including airway obstruction, descending necrotizing mediastinitis, orbital abscess, septic cavernous sinus thrombosis, cerebral abscess, sepsis, necrotizing fasciitis, and Lemierre's syndrome. The purpose of this article is to discuss the pathophysiology of severe odontogenic infections and the risk factors associated with the development of complications. Given the morbidity and mortality of these conditions, it is important to review the clinical features of each and the diagnostic tools that aid in early recognition.

A Journey to the Central Nervous System: Routes of Flaviviral Neuroinvasion in Human Disease

Many arboviruses, including viruses of the Flavivirus genera, are known to cause severe neurological disease in humans, often with long-lasting, debilitating sequalae in surviving patients. These emerging pathogens impact millions of people worldwide, yet still relatively little is known about the exact mechanisms by which they gain access to the human central nervous system. This review focusses on potential haematogenous and transneural routes of neuroinvasion employed by flaviviruses and identifies numerous gaps in knowledge, especially regarding lesser-studied interfaces of possible invasion such as the blood-cerebrospinal fluid barrier, and novel routes such as the gut-brain axis. The complex balance of pro-inflammatory and antiviral immune responses to viral neuroinvasion and pathology is also discussed, especially in the context of the hypothesised Trojan horse mechanism of neuroinvasion. A greater understanding of the routes and mechanisms of arboviral neuroinvasion, and how they differ between viruses, will aid in predictive assessments of the neuroinvasive potential of new and emerging arboviruses, and may provide opportunity for attenuation, development of novel intervention strategies and rational vaccine design for highly neurovirulent arboviruses.

Diabetes Mellitus and Dental Implants: A Systematic Review and Meta-Analysis

The present review aimed to evaluate the impact of diabetes mellitus on dental implant failure rates and marginal bone loss (MBL). An electronic search was undertaken in three databases, plus a manual search of journals. Meta-analyses were performed as well as meta-regressions in order to verify how the odds ratio (OR) and MBL were associated with follow-up time. The review included 89 publications. Altogether, there were 5510 and 62,780 implants placed in diabetic and non-diabetic patients, respectively. Pairwise meta-analysis showed that implants in diabetic patients had a higher failure risk in comparison to non-diabetic patients (OR 1.777, p < 0.001). Implant failures were more likely to occur in type 1 diabetes patients than in type 2 (OR 4.477, p = 0.032). The difference in implant failure between the groups was statistically significant in the maxilla but not in the mandible. The MBL mean difference (MD) between the groups was 0.776 mm (p = 0.027), with an estimated increase of 0.032 mm in the MBL MD between groups for every additional month of follow-up (p < 0.001). There was an estimated decrease of 0.007 in OR for every additional month of follow-up (p = 0.048). In conclusion, implants in diabetic patients showed a 77.7% higher risk of failure than in non-diabetic patients.

Coupled small molecules target RNA interference and JAK/STAT signaling to reduce Zika virus infection in Aedes aegypti

The recent global Zika epidemics have revealed the significant threat that mosquito-borne viruses pose. There are currently no effective vaccines or prophylactics to prevent Zika virus (ZIKV) infection. Limiting exposure to infected mosquitoes is the best way to reduce disease incidence. Recent studies have focused on targeting mosquito reproduction and immune responses to reduce transmission. Previous work has evaluated the effect of insulin signaling on antiviral JAK/STAT and RNAi in vector mosquitoes. Specifically, insulin-fed mosquitoes resulted in reduced virus replication in an RNAi-independent, ERK-mediated JAK/STAT-dependent mechanism. In this work, we demonstrate that targeting insulin signaling through the repurposing of small molecule drugs results in the activation of both RNAi and JAK/STAT antiviral pathways. ZIKV-infected Aedes aegypti were fed blood containing demethylasterriquinone B1 (DMAQ-B1), a potent insulin mimetic, in combination with AKT inhibitor VIII. Activation of this coordinated response additively reduced ZIKV levels in Aedes aegypti. This effect included a quantitatively greater reduction in salivary gland ZIKV levels up to 11 d post-bloodmeal ingestion, relative to single pathway activation. Together, our study indicates the potential for field delivery of these small molecules to substantially reduce virus transmission from mosquito to human. As infections like Zika virus are becoming more burdensome and prevalent, understanding how to control this family of viruses in the insect vector is an important issue in public health.

SARS-CoV-2 Infects Primary Neurons from Human ACE2 Expressing Mice and Upregulates Genes Involved in the Inflammatory and Necroptotic Pathways

Transgenic mice expressing human angiotensin-converting enzyme 2 under the cytokeratin 18 promoter (K18-hACE2) have been extensively used to investigate the pathogenesis and tissue tropism of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Neuroinvasion and the replication of SARS-CoV-2 within the central nervous system (CNS) of K18-hACE2 mice is associated with increased mortality; although, the mechanisms by which this occurs remain unclear. In this study, we generated primary neuronal cultures from K18-hACE2 mice to investigate the effects of a SARS-CoV-2 infection. We also evaluated the immunological response to SARS-CoV-2 infection in the CNS of K18-hACE2 mice and mouse neuronal cultures. Our data show that neuronal cultures obtained from K18-hACE2 mice are permissive to SARS-CoV-2 infection and support productive virus replication. Furthermore, SARS-CoV-2 infection upregulated the expression of genes involved in innate immunity and inflammation, including IFN-α, ISG-15, CXCL10, CCL2, IL-6 and TNF-α, in the neurons and mouse brains. In addition, we found that SARS-CoV-2 infection of neurons and mouse brains activates the ZBP1/pMLKL-regulated necroptosis pathway. Together, our data provide insights into the neuropathogenesis of SARS-CoV-2 infection in K18-hACE2 mice.

Infection and Immunometabolism in the Central Nervous System: A Possible Mechanistic Link Between Metabolic Imbalance and Dementia

Metabolic syndromes are frequently associated with dementia, suggesting that the dysregulation of energy metabolism can increase the risk of neurodegeneration and cognitive impairment. In addition, growing evidence suggests the link between infections and brain disorders, including Alzheimer's disease. The immune system and energy metabolism are in an intricate relationship. Infection triggers immune responses, which are accompanied by imbalance in cellular and organismal energy metabolism, while metabolic disorders can lead to immune dysregulation and higher infection susceptibility. In the brain, the activities of brain-resident immune cells, including microglia, are associated with their metabolic signatures, which may be affected by central nervous system (CNS) infection. Conversely, metabolic dysregulation can compromise innate immunity in the brain, leading to enhanced CNS infection susceptibility. Thus, infection and metabolic imbalance can be intertwined to each other in the etiology of brain disorders, including dementia. Insulin and leptin play pivotal roles in the regulation of immunometabolism in the CNS and periphery, and dysfunction of these signaling pathways are associated with cognitive impairment. Meanwhile, infectious complications are often comorbid with diabetes and obesity, which are characterized by insulin resistance and leptin signaling deficiency. Examples include human immunodeficiency virus (HIV) infection and periodontal disease caused by an oral pathogen Porphyromonas gingivalis. This review explores potential interactions between infectious agents and insulin and leptin signaling pathways, and discuss possible mechanisms underlying the relationship between infection, metabolic dysregulation, and brain disorders, particularly focusing on the roles of insulin and leptin.

The role of T-cell immunity in COVID-19 severity amongst people living with type II diabetes

The COVID-19 pandemic has highlighted the vulnerability of people with diabetes mellitus (DM) to respiratory viral infections. Despite the short history of COVID-19, various studies have shown that patients with DM are more likely to have increased hospitalisation and mortality rates as compared to patients without. At present, the mechanisms underlying this susceptibility are unclear. However, prior studies show that the course of COVID-19 disease is linked to the efficacy of the host's T-cell responses. Healthy individuals who can elicit a robust T-cell response are more likely to limit the severity of COVID-19. Here, we investigate the hypothesis that an impaired T-cell response in patients with type 2 diabetes mellitus (T2DM) drives the severity of COVID-19 in this patient population. While there is currently a limited amount of information that specifically addresses T-cell responses in COVID-19 patients with T2DM, there is a wealth of evidence from other infectious diseases that T-cell immunity is impaired in patients with T2DM. The reasons for this are likely multifactorial, including the presence of hyperglycaemia, glycaemic variability and metformin use. This review emphasises the need for further research into T-cell responses of COVID-19 patients with T2DM in order to better inform our response to COVID-19 and future disease outbreaks.

Blood glucose promotes dengue virus infection in the mosquito Aedes aegypti

Background

Dengue fever is the most rapidly spreading mosquito-borne viral disease globally. More than 2.5 billion people live in dengue-endemic areas. Previous studies suggested an interrelationship between diabetes mellitus (DM) and dengue hemorrhagic fever (DHF). Conversely, glycolysis is a critical metabolic pathway for optimal dengue virus (DENV) replication. However, little is known concerning the effect of glucose on DENV replication in mosquitoes. In this study, we investigated the impact of glucose on DENV replication in mosquitoes Aedes aegypti.

Methods

Mosquitoes (Ae. aegypti UGAL/Rockefeller strain) were orally infected with DENV (serotype 2, 16681 strain) through infectious blood feeding. The DENV infection and transmission rates were determined by examining mosquito bodies and saliva, respectively, for DENV positivity at different time points after infection. In addition, a reverse genetic approach was applied by introducing double-stranded RNA against genes of interest into the mosquitoes to inhibit gene expression.

Results

Our data revealed a significant increase of DENV genome levels in mosquitoes consuming an infectious blood meal supplemented with glucose, suggesting that blood glucose is an important factor for viral replication. Interestingly, a significant increase of DENV E protein levels was detected in the saliva 4 days faster in mosquitoes that consumed infectious blood meals supplemented with glucose than in those consuming infectious blood meals alone. Furthermore, we perform RNAi to silence AKT or TOR and investigate the molecular mechanism regulating the glucose-mediated enhancement of viral replication. Silencing of AKT or TOR significantly reduced DENV titers in mosquitoes.

Conclusions

This study suggested that blood glucose is beneficial to DENV replication and that it facilitates virus transmission in mosquitoes via AKT and TOR signaling. Therefore, our results strengthen our understanding of dengue fever and DM co-morbidity and possibly reveal new targets for specific antiviral therapies.

Graphical abstract

Elevated glycohemoglobin is linked to critical illness in CoVID-19: a retrospective analysis

Background

Several studies have explored hospitalization risk factors with the novel coronavirus disease 2019 (COVID-19) infection. Our goal was to identify clinical characteristics outside of laboratory or radiologic data associated with intubation or death within 7 days of admission.

Methods

The first 436 patients admitted to the University of Colorado Hospital (Denver metropolitan area) with confirmed COVID-19 were included. Demographics, comorbidities, and select medications were collected by chart abstraction. Missing height for calculating body mass index (BMI) was imputed using the median height for patients' sex and race/ethnicity. Adjusted odds ratios (aOR) were estimated using multivariable logistic regression and a minimax concave penalty (MCP) regularized logistic regression explored prediction.

Results

Participants had a mean [standard deviation (SD)] age 55 (17), BMI 30.9 (8.2), 55% were male and 80% were ethnic/racial minorities. Increasing age [aOR: 1.24 (1.07, 1.45) per 10 years], higher BMI (aOR 1.03 (1.00, 1.06), and poorly controlled diabetes [hemoglobin A1C (HbA1c) ⩾ 8] (aOR 2.26 (1.24, 4.12) were significantly (p < 0.05) associated with greater odds of intubation or death. Female sex [aOR: 0.63, 95% CI (0.40, 0.98); p value = 0.043] was associated with lesser odds of intubation or death. The odds of death and/or intubation increased 19% for every 1 unit increase in HbA1c value [OR: 1.19 (1.01, 1.43); p = 0.04]. Our final MCP model included indicators of A1C ⩾ 8, age > 65, sex, and minority status, but predicted intubation/death only slightly better than random chance [area under the receiver operating characteristic curve (AUC) = 0.61 (0.56, 0.67)].

Conclusion

In a hospitalized patient cohort with COVID-19, worsening control of diabetes as evidenced by higher HbA1c was associated with increased risk of intubation or death within 7 days of admission. These results complement and help clarify previous associations found between diabetes and acute disease in COVID-19. Importantly, our analysis is missing some known predictors of severity in COVID-19. Our predictive model had limited success, suggesting unmeasured factors contribute to disease severity differences.

Host Factors That Control Mosquito-Borne Viral Infections in Humans and Their Vector

Mosquito-borne viral infections are responsible for a significant degree of morbidity and mortality across the globe due to the severe diseases these infections cause, and they continue to increase each year. These viruses are dependent on the mosquito vector as the primary means of transmission to new vertebrate hosts including avian, livestock, and human populations. Due to the dynamic host environments that mosquito-borne viruses pass through as they are transmitted between vector and vertebrate hosts, there are various host factors that control the response to infection over the course of the pathogen's life cycle. In this review, we discuss these host factors that are present in either vector or vertebrate models during infection, how they vary or are conserved between hosts, and their implications in future research pertaining to disease prevention and treatment.

Deletion of B-cell translocation gene 2 (BTG2) alters the responses of glial cells in white matter to chronic cerebral hypoperfusion

BACKGROUND

Subcortical ischemic vascular dementia, one of the major subtypes of vascular dementia, is characterized by lacunar infarcts and white matter lesions caused by chronic cerebral hypoperfusion. In this study, we used a mouse model of bilateral common carotid artery stenosis (BCAS) to investigate the role of B-cell translocation gene 2 (BTG2), an antiproliferation gene, in the white matter glial response to chronic cerebral hypoperfusion.

METHODS

Btg2-/- mice and littermate wild-type control mice underwent BCAS or sham operation. Behavior phenotypes were assessed by open-field test and Morris water maze test. Brain tissues were analyzed for the degree of white matter lesions and glial changes. To further confirm the effects of Btg2 deletion on proliferation of glial cells in vitro, BrdU incorporation was investigated in mixed glial cells derived from wild-type and Btg2-/- mice.

RESULTS

Relative to wild-type mice with or without BCAS, BCAS-treated Btg2-/- mice exhibited elevated spontaneous locomotor activity and poorer spatial learning ability. Although the severities of white matter lesions did not significantly differ between wild-type and Btg2-/- mice after BCAS, the immunoreactivities of GFAP, a marker of astrocytes, and Mac2, a marker of activated microglia and macrophages, in the white matter of the optic tract were higher in BCAS-treated Btg2-/- mice than in BCAS-treated wild-type mice. The expression level of Gfap was also significantly elevated in BCAS-treated Btg2-/- mice. In vitro analysis showed that BrdU incorporation in mixed glial cells in response to inflammatory stimulation associated with cerebral hypoperfusion was higher in Btg2-/- mice than in wild-type mice.

CONCLUSION

BTG2 negatively regulates glial cell proliferation in response to cerebral hypoperfusion, resulting in behavioral changes.

GR/NF-κB signaling pathway regulates hippocampal inflammatory responses in diabetic rats with chronic unpredictable mild stress

Clinical studies have shown that diabetes can present with underlying depression, and a combination of the two can lead to emotional, memory and cognitive disorders, closely associated with hippocampal neuroinflammation. However, the mechanism underlying the development of hippocampal neuroinflammation under the above condition remains elusive. The aims of this study were to explore the pathogenesis of diabetes combined with depression, and the effect of dexamethasone (Dex), a glucocorticoid receptor (GR) agonist, on hippocampal neuroinflammation in diabetic rats with chronic unpredictable mild stress (CUMS). Therefore, rats were intragastrically fed on a high-fat diet (10% cholesterol 10 ml/kg) for 14 days and thereafter injected with 38 mg/kg of streptozotocin on the 15th day to induce diabetes. Dex treatment of the diabetic and CUMS rats ameliorated the depression-associated behavior in the respective rats. Apart from enhanced depressive behavior, diabetes-depressed condition also up-regulated the expression of hippocampus microglia chemokine Ⅰ receptor (CX3CR1) and secretion of several pro-inflammatory factors, in particular, interleukin 1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor - α (TNF-α). Hematoxylin-eosin staining revealed inflammatory damages in the hippocampus. Western blot analysis further revealed repression of GR proteins converse to the nuclear factor kappa-B (NF-κB) proteins, which were up-regulated. Intriguingly, Dex reversed the above events by inhibiting inflammatory reactions in the hippocampus. Consequently, played an antidepressant effect in diabetic and CUMS model rats. Overall, findings of this research suggest that the physiopathology of diabetes with stress cormobity are mediated by inflammatory reactions in the hippocampus. In particular, the responses are associated with regulation of GR/NF-κB signaling pathway.

Dysregulation of Leukocyte Trafficking in Type 2 Diabetes: Mechanisms and Potential Therapeutic Avenues

Type 2 Diabetes Mellitus (T2DM) is a chronic inflammatory disorder that is characterized by chronic hyperglycemia and impaired insulin signaling which in addition to be caused by common metabolic dysregulations, have also been associated to changes in various immune cell number, function and activation phenotype. Obesity plays a central role in the development of T2DM. The inflammation originating from obese adipose tissue develops systemically and contributes to insulin resistance, beta cell dysfunction and hyperglycemia. Hyperglycemia can also contribute to chronic, low-grade inflammation resulting in compromised immune function. In this review, we explore how the trafficking of innate and adaptive immune cells under inflammatory condition is dysregulated in T2DM. We particularly highlight the obesity-related accumulation of leukocytes in the adipose tissue leading to insulin resistance and beta-cell dysfunction and resulting in hyperglycemia and consequent changes of adhesion and migratory behavior of leukocytes in different vascular beds. Thus, here we discuss how potential therapeutic targeting of leukocyte trafficking could be an efficient way to control inflammation as well as diabetes and its vascular complications.

Neuroinvasion and Encephalitis Following Intranasal Inoculation of SARS-CoV-2 in K18-hACE2 Mice

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection can cause neurological disease in humans, but little is known about the pathogenesis of SARS-CoV-2 infection in the central nervous system (CNS). Herein, using K18-hACE2 mice, we demonstrate that SARS-CoV-2 neuroinvasion and encephalitis is associated with mortality in these mice. Intranasal infection of K18-hACE2 mice with 10⁵ plaque-forming units of SARS-CoV-2 resulted in 100% mortality by day 6 after infection. The highest virus titers in the lungs were observed on day 3 and declined on days 5 and 6 after infection. By contrast, very high levels of infectious virus were uniformly detected in the brains of all the animals on days 5 and 6. Onset of severe disease in infected mice correlated with peak viral levels in the brain. SARS-CoV-2-infected mice exhibited encephalitis hallmarks characterized by production of cytokines and chemokines, leukocyte infiltration, hemorrhage and neuronal cell death. SARS-CoV-2 was also found to productively infect cells within the nasal turbinate, eye and olfactory bulb, suggesting SARS-CoV-2 entry into the brain by this route after intranasal infection. Our data indicate that direct infection of CNS cells together with the induced inflammatory response in the brain resulted in the severe disease observed in SARS-CoV-2-infected K18-hACE2 mice.

Application of 3D Bioprinting Technologies to the Management and Treatment of Diabetic Foot Ulcers

Diabetes mellitus (DM) is a chronic metabolic disease with increasing prevalence worldwide. Diabetic foot ulcers (DFUs) are a serious complication of DM. It is estimated that 15-25% of DM patients develop DFU at least once in their lifetime. The lack of effective wound dressings and targeted therapy for DFUs often results in prolonged hospitalization and amputations. As the incidence of DM is projected to rise, the demand for specialized DFU wound management will continue to increase. Hence, it is of great interest to improve and develop effective DFU-specific wound dressings and therapies. In the last decade, 3D bioprinting technology has made a great contribution to the healthcare sector, with the development of personalized prosthetics, implants, and bioengineered tissues. In this review, we discuss the challenges faced in DFU wound management and how 3D bioprinting technology can be applied to advance current treatment methods, such as biomanufacturing of composite 3D human skin substitutes for skin grafting and the development of DFU-appropriate wound dressings. Future co-development of 3D bioprinting technologies with novel treatment approaches to mitigate DFU-specific pathophysiological challenges will be key to limiting the healthcare burden associated with the increasing prevalence of DM.

Insulin Potentiates JAK/STAT Signaling to Broadly Inhibit Flavivirus Replication in Insect Vectors

The World Health Organization estimates that more than half of the world’s population is at risk for vector-borne diseases, including arboviruses. Because many arboviruses are mosquito borne, investigation of the insect immune response will help identify targets to reduce the spread of arboviruses. Here, we use a genetic screening approach to identify an insulin-like receptor as a component of the immune response to arboviral infection. We determine that vertebrate insulin reduces West Nile virus (WNV) replication in Drosophila melanogaster as well as WNV, Zika, and dengue virus titers in mosquito cells. Mechanistically, we show that insulin signaling activates the JAK/STAT, but not RNAi, pathway via ERK to control infection in Drosophila cells and Culex mosquitoes through an integrated immune response. Finally, we validate that insulin priming of adult female Culex mosquitoes through a blood meal reduces WNV infection, demonstrating an essential role for insulin signaling in insect antiviral responses to human pathogens.

The world’s population is at risk for infection with several flaviviruses. Ahlers et al. use a living library of insects to determine that an insulin-like receptor controls West Nile virus infection. Insulin signaling is antiviral via the JAK/STAT pathway in both fly and mosquito models and against a range of flaviviruses.

Lipid and Lipoprotein Metabolism in Microglia

Microglia, once viewed as static bystanders with limited homeostatic functions, are now considered key players in the development of neuroinflammatory and neurodegenerative diseases. Microglial activation is a salient feature of neuroinflammation involving a dynamic process that generates multitudinous microglial phenotypes that can respond to a variety of situational cues in the central nervous system. Recently, a flurry of single cell RNA-sequencing studies have defined microglial phenotypes in unprecedented detail, and have highlighted robust changes in the expression of genes involved in lipid and lipoprotein metabolism. Increased expression of genes such as Apolipoprotein E (ApoE), Triggering Receptor Expressed on Myeloid Cells 2 (TREM2) and Lipoprotein Lipase (LPL) in microglia during development, damage, and disease, suggest that increased lipid metabolism is needed to fuel protective cellular functions such as phagocytosis. This review describes our current understanding of lipid and lipoprotein metabolism in microglia, and highlights microglial lipid metabolism as a modifiable target for the treatment of neurodegenerative diseases such as Alzheimer's disease and multiple sclerosis.

Type 2 Diabetes and its Impact on the Immune System

INTRODUCTION

Type 2 Diabetes (T2D) is a major health problem worldwide. This metabolic disease is indicated by high blood glucose levels due to insufficient insulin production by the pancreas. An inflammatory response occurs as a result of the immune response to high blood glucose levels as well as the presence of inflammatory mediators produced by adipocytes and macrophages in fat tissue. This low and chronic inflammation damages the pancreatic beta cells and leads to insufficient insulin production, which results in hyperglycemia. Hyperglycemia in diabetes is thought to cause dysfunction of the immune response, which fails to control the spread of invading pathogens in diabetic subjects. Therefore, diabetic subjects are known to more susceptible to infections. The increased prevalence of T2D will increase the incidence of infectious diseases and related comorbidities.

OBJECTIVE

This review provides an overview of the immunological aspect of T2D and the possible mechanisms that result in increased infections in diabetics.

CONCLUSION

A better understanding of how immune dysfunctions occur during hyperglycemia can lead to novel treatments and preventions for infectious diseases and T2D comorbidities, thus improving the outcome of infectious disease treatment in T2D patients.

Cellular microRNA-155 Regulates Virus-Induced Inflammatory Response and Protects against Lethal West Nile Virus Infection

West Nile virus (WNV) is a flavivirus that has disseminated globally as a significant cause of viral encephalitis in humans. MircoRNA-155 (miR-155) regulates various aspects of innate and adaptive immune responses. We previously reported that WNV infection induces upregulation of miR-155 in mice brains. In the current study, we demonstrate the critical role of miR-155 in restricting the pathogenesis of WNV infection in mice. Compared to wild-type (WT) mice, miR-155 knockout mice exhibited significantly higher morbidity and mortality after infection with either a lethal strain, WNV NY99, or a non-lethal strain, WNV Eg101. Increased mortality in miR-155^−/− mice was associated with significantly high WNV burden in the serum and brains. Protein levels of interferon (IFN)-α in the serum and brains were higher in miR-155^−/− mice. However, miR-155^−/− mice exhibited significantly lower protein levels of anti-viral interleukin (IL)-1β, IL-12, IL-6, IL-15, and GM-CSF despite the high viral load. Primary mouse cells lacking miR-155 were more susceptible to infection with WNV compared to cells derived from WT mice. Besides, overexpression of miR-155 in human neuronal cells modulated anti-viral cytokine response and resulted in significantly lower WNV replication. These data collectively indicate that miR-155 restricts WNV production in mouse and human cells and protects against lethal WNV infection in mice.

West Nile Virus Induced Cell Death in the Central Nervous System

West Nile virus (WNV), a mosquito-borne, single-stranded flavivirus, has caused annual outbreaks of viral encephalitis in the United States since 1999. The virus induces acute infection with a clinical spectrum ranging from a mild flu-like febrile symptom to more severe neuroinvasive conditions, including meningitis, encephalitis, acute flaccid paralysis, and death. Some WNV convalescent patients also developed long-term neurological sequelae. Neither the treatment of WNV infection nor an approved vaccine is currently available for humans. Neuronal death in the central nervous system (CNS) is a hallmark of WNV-induced meningitis and encephalitis. However, the underlying mechanisms of WNV-induced neuronal damage are not well understood. In this review, we discuss current findings from studies of WNV infection in vitro in the CNS resident cells and the in vivo animal models, and provide insights into WNV-induced neuropathogenesis.

Z-DNA-Binding Protein 1 Is Critical for Controlling Virus Replication and Survival in West Nile Virus Encephalitis

West Nile virus (WNV), a neurotropic flavivirus, is the leading cause of viral encephalitis in the United States. Recently, Zika virus (ZIKV) infections have caused serious neurological diseases and birth defects, specifically Guillain-Barrè syndrome and microcephaly. Z-DNA binding protein 1 (ZBP1) is a cytoplasmic sensor that that has been shown to play a significant role in initiating a robust immune response. We previously reported that WNV and ZIKV infections induce dramatic up-regulation of ZBP1 in mouse brains as well as in infected primary mouse cells. Herein, we show the critical role of ZBP1 in restricting the pathogenesis of WNV and ZIKV infections. Deletion of ZBP1 resulted in significantly higher morbidity and mortality after infection with a pathogenic WNV NY99 strain in mice. No mortality was observed in wild-type (WT) mice infected with the non-pathogenic WNV strain, Eg101. Interestingly, infection of ZBP1^-/- mice with WNV Eg101 was lethal resulting in 100% mortality, suggesting that ZBP1 is required for survival after WNV infection. Viremia and brain viral load were significantly higher in ZBP1^-/- mice compared to WT mice. In addition, protein levels of interferon (IFN)-α, and inflammatory cytokines and chemokines were significantly higher in the serum and brains of infected ZBP1^-/- mice compared to the WT mice. Primary mouse cortical neurons and mouse embryonic fibroblasts (MEFs) derived from ZBP1^-/- mice produced higher virus titers compared to WT cells after infection with WNV NY99 and WNV Eg101. Similarly, neurons and MEFs lacking ZBP1 exhibited significantly enhanced replication of PRVABC59 (Asian) and MR766 (African) ZIKV compared to WT cells. The knockout of ZBP1 function in MEFs inhibited ZBP1-dependent virus-induced cell death. In conclusion, these data reveal that ZBP1 restricts WNV and ZIKV production in mouse cells and is required for survival of a peripheral WNV infection in mice.

Momordica charantia (bitter melon) modulates adipose tissue inflammasome gene expression and adipose-gut inflammatory cross talk in high-fat diet (HFD)-fed mice

Systemic and tissue-specific inflammation has a profound influence on regulation of metabolism, and therefore, strategies to reduce inflammation are of special interest in prevention and treatment of obesity and type 2 diabetes (T2D). Antiobesity and antidiabetic properties of Momordica charantia (bitter melon, BM) have been linked to its protective effects on inflammation and gut microbial dysbiosis. We investigated the mechanisms by which freeze-dried BM juice reduces adipose inflammation in mice fed a 60% high-fat diet (HFD) for 16 weeks. Although earlier studies indicated that BM inhibited recruitment of macrophages (Mφ) infiltration in adipose tissue of rodents and reduced NF-kB and IL-1β secretions, the mechanisms remain unknown. We demonstrate that freeze-dried BM juice inhibits recruitment of Mφ into adipose tissue and its polarization to inflammatory phenotype possibly due to reduction of sphingokinase 1 (SPK1) mRNA in HFD-fed mice. Furthermore, reduction of IL-1β secretion by freeze-dried BM juice in the adipose tissue of HFD-fed mice is correlated to alleviation of NLRP3 inflammasome components and their downstream signaling targets. We confirm previous observations that BM inhibited inflammation of colon and gut microbial dysbiosis in HFD-fed mice, which in part may be associated with the observed anti-inflammatory effects in adipose tissue if HFD-fed mice. Overall, functional foods such as BM may offer potential dietary interventions that may impact sterile inflammatory diseases such as obesity and T2D.

Deletion of Pregnancy Zone Protein and Murinoglobulin-1 Restricts the Pathogenesis of West Nile Virus Infection in Mice

West Nile virus (WNV) is an enveloped positive-stranded RNA virus that causes meningitis, encephalitis, and acute flaccid paralysis in humans. There are no therapeutic agents available for use against WNV infection. Alpha-2 macroglobulin (A2M) is a major plasma proteinase inhibitor that also has important role in immune modulation. In mice, pregnancy zone protein (PZP) and murinoglobulin-1 (MUG-1) are two close homologous of human A2M. In this study, we investigated the role of PZP and MUG-1 proteins in the pathogenesis of WNV infection in mice. Adult C57BL/6J wild-type and PZP/MUG-1 double knockout (DKO) mice were inoculated subcutaneously with WNV and mortality, virus burden, and immune responses were analyzed. Infection of wild-type (WT) mice with WNV resulted in significantly high morbidity and mortality. In comparison, no mortality was observed in DKO mice, suggesting that PZP and MUG-1 play a deleterious role in WNV infection. Increased survival in WNV-infected DKO mice was associated with significantly low viral burden in serum, spleen, kidney, and brain compared to WT mice. In addition, significantly reduced levels of type 1 interferon and WNV-specific antibodies were observed in the DKO mice compared to WT mice. We further demonstrated that protein levels of inflammatory cytokines and chemokines in the serum, spleen, and brain were significantly reduced in DKO mice compared to WT mice. Collectively our data demonstrate that lack of PZP and MUG-1 restricts the pathogenesis of WNV infection in mice.

Astrocytes in Flavivirus Infections

Virus infections of the central nervous system (CNS) can manifest in various forms of inflammation, including that of the brain (encephalitis) and spinal cord (myelitis), all of which may have long-lasting deleterious consequences. Although the knowledge of how different viruses affect neural cells is increasing, understanding of the mechanisms by which cells respond to neurotropic viruses remains fragmented. Several virus types have the ability to infect neural tissue, and astrocytes, an abundant and heterogeneous neuroglial cell type and a key element providing CNS homeostasis, are one of the first CNS cell types to get infected. Astrocytes are morphologically closely aligned with neuronal synapses, blood vessels, and ventricle cavities, and thereby have the capacity to functionally interact with neurons and endothelial cells. In this review, we focus on the responses of astrocytes to infection by neurotropic flaviviruses, including tick-borne encephalitis virus (TBEV), Zika virus (ZIKV), West Nile virus (WNV), and Japanese encephalitis virus (JEV), which have all been confirmed to infect astrocytes and cause multiple CNS defects. Understanding these mechanisms may help design new strategies to better contain and mitigate virus- and astrocyte-dependent neuroinflammation.

Innate Immune Response of Primary Human Keratinocytes to West Nile Virus Infection and Its Modulation by Mosquito Saliva

West Nile Virus (WNV) is a flavivirus involved in many human infections worldwide. This arthropod-borne virus is directly co-inoculated with mosquito saliva through the epidermis and the dermis during blood meal. WNV starts replicating in the skin before migrating to the draining lymph node, leading to widespread viremia and in some cases to neurological symptoms. Skin is a complex organ composed of different cell types that together perform essential functions such as pathogen sensing, barrier maintenance and immunity. Keratinocytes, which represent 90% of the cells of the epidermis, are the organism's first line of defense, initiating innate immune response by recognizing pathogens through their pattern recognition receptors. Although WNV was previously known to replicate in human primary keratinocytes, the induced inflammatory response remains unknown. The aim of this study was first to characterize the inflammatory response of human primary keratinocytes to WNV infection and then, to assess the potential role of co-inoculated mosquito saliva on the keratinocyte immune response and viral replication. A type I and III interferon inflammatory response associated with an increase of IRF7 but not IRF3 mRNA expression, and dependent on infectious dose, was observed during keratinocyte infection with WNV. Expression of several interferon-stimulated gene mRNA was also increased at 24 h post-infection (p.i.); they included CXCL10 and interferon-induced proteins with tetratricopeptide repeats (IFIT)-2 sustained up until 48 h p.i. Moreover, WNV infection of keratinocyte resulted in a significant increase of pro-inflammatory cytokines (TNFα, IL-6) and various chemokines (CXCL1, CXCL2, CXCL8 and CCL20) expression. The addition of Aedes aegypti or Culex quinquefasciatus mosquito saliva, two vectors of WNV infection, to infected keratinocytes led to a decrease of inflammatory response at 24 h p.i. However, only Ae. Aegypti saliva adjunction induced modulation of viral replication. In conclusion, this work describes for the first time the inflammatory response of human primary keratinocytes to WNV infection and its modulation in presence of vector mosquito saliva. The effects of mosquito saliva assessed in this work could be involved in the early steps of WNV replication in skin promoting viral spread through the body.

Transcriptional Profiling of Immune-Related Genes in Leishmania infantum-Infected Mice: Identification of Potential Biomarkers of Infection and Progression of Disease

Leishmania spp. is a protozoan parasite that affects millions of people around the world. At present, there is no effective vaccine to prevent leishmaniases in humans. A major limitation in vaccine development is the lack of precise understanding of the particular immunological mechanisms that allow parasite survival in the host. The parasite-host cell interaction induces dramatic changes in transcriptome patterns in both organisms, therefore, a detailed analysis of gene expression in infected tissues will contribute to the evaluation of drug and vaccine candidates, the identification of potential biomarkers, and the understanding of the immunological pathways that lead to protection or progression of disease. In this large-scale analysis, differential expression of 112 immune-related genes has been analyzed using high-throughput qPCR in spleens of infected and naïve Balb/c mice at four different time points. This analysis revealed that early response against Leishmania infection is characterized by the upregulation of Th1 markers and M1-macrophage activation molecules such as Ifng, Stat1, Cxcl9, Cxcl10, Ccr5, Cxcr3, Xcl1, and Ccl3. This activation doesn't protect spleen from infection, since parasitic burden rises along time. This marked difference in gene expression between infected and control mice disappears during intermediate stages of infection, probably related to the strong anti-inflammatory and immunosuppresory signals that are activated early upon infection (Ctla4) or remain activated throughout the experiment (Il18bp). The overexpression of these Th1/M1 markers is restored later in the chronic phase (8 wpi), suggesting the generation of a classical "protective response" against leishmaniasis. Nonetheless, the parasitic burden rockets at this timepoint. This apparent contradiction can be explained by the generation of a regulatory immune response characterized by overexpression of Ifng, Tnfa, Il10, and downregulation Il4 that counteracts the Th1/M1 response. This large pool of data was also used to identify potential biomarkers of infection and parasitic burden in spleen, on the bases of two different regression models. Given the results, gene expression signature analysis appears as a useful tool to identify mechanisms involved in disease outcome and to establish a rational approach for the identification of potential biomarkers useful for monitoring disease progression, new therapies or vaccine development.

Risk of Infection in Type 1 and Type 2 Diabetes Compared With the General Population: A Matched Cohort Study

OBJECTIVE

We describe in detail the burden of infections in adults with diabetes within a large national population cohort. We also compare infection rates between patients with type 1 and type 2 diabetes mellitus (T1DM and T2DM).

RESEARCH DESIGN AND METHODS

A retrospective cohort study compared 102,493 English primary care patients aged 40-89 years with a diabetes diagnosis by 2008 (n = 5,863 T1DM and n = 96,630 T2DM) with 203,518 age-sex-practice-matched control subjects without diabetes. Infection rates during 2008-2015, compiled from primary care and linked hospital and mortality records, were compared across 19 individual infection categories. These were further summarized as any requiring a prescription or hospitalization or as cause of death. Poisson regression was used to estimate incidence rate ratios (IRRs) between 1) people with diabetes and control subjects and 2) T1DM and T2DM adjusted for age, sex, smoking, BMI, and deprivation.

RESULTS

Compared with control subjects without diabetes, patients with diabetes had higher rates for all infections, with the highest IRRs seen for bone and joint infections, sepsis, and cellulitis. IRRs for infection-related hospitalizations were 3.71 (95% CI 3.27-4.21) for T1DM and 1.88 (95% CI 1.83-1.92) for T2DM. A direct comparison of types confirmed higher adjusted risks for T1DM versus T2DM (death from infection IRR 2.19 [95% CI 1.75-2.74]). We estimate that 6% of infection-related hospitalizations and 12% of infection-related deaths were attributable to diabetes.

CONCLUSIONS

People with diabetes, particularly T1DM, are at increased risk of serious infection, representing an important population burden. Strategies that reduce the risk of developing severe infections and poor treatment outcomes are under-researched and should be explored.

Favipiravir and Ribavirin Inhibit Replication of Asian and African Strains of Zika Virus in Different Cell Models

Zika virus (ZIKV) has recently emerged as a new public health threat. ZIKV infections have caused a wide spectrum of neurological diseases, such as Guillain-Barré syndrome, myelitis, meningoencephalitis, and congenital microcephaly. No effective therapies currently exist for treating patients infected with ZIKV. Herein, we evaluated the anti-viral activity of favipiravir (T-705) and ribavirin against Asian and African strains of ZIKV using different cell models, including human neuronal progenitor cells (hNPCs), human dermal fibroblasts (HDFs), human lung adenocarcinoma cells (A549) and Vero cells. Cells were treated with favipiravir or ribavirin and effects on ZIKV replication were determined using quantitative real-time PCR and plaque assay. Our results demonstrate that favipiravir or ribavirin treatment significantly inhibited ZIKV replication in a dose-dependent manner. Moreover, favipiravir treatment of ZIKV-infected hNPCs led to reduced cell death, enhanced AKT pathway phosphorylation, and increased expression of anti-apoptotic factor B cell lymphoma 2. In conclusion, our results demonstrate conclusively that favipiravir inhibits ZIKV replication and prevents cell death, and can be a promising intervention for ZIKV-associated disease.

A Mouse Model of West Nile Virus Infection

The use of a mouse model to study the breadth of symptoms and disease severity seen in human West Nile virus (WNV) infection can provide insight into the kinetics of the immune response and the specific pathways responsible for control of WNV infection and viral clearance. Here, we provide protocols for performing WNV infection of mice, as well as complete immunophenotyping analysis of the cellular immune response to infection in both the periphery and the central nervous system in a mouse model of WNV infection. © 2017 by John Wiley & Sons, Inc.

Interleukin gene polymorphisms in Chinese Han population with breast cancer, a case-control study

Cytokines are known as important regulators of the cancer involved in inflammatory and immunological responses. This fact and plethora of gene polymorphism data prompted us to investigate IL1 gene polymorphisms in breast cancer (BC) patients. Totally, 530 patients with BC and 628 healthy control women were studied. The genetic polymorphisms for IL1 were analyzed by Massarray Sequencing method. Three single nucleotide polymorphisms (SNPs) identified in IL1B, IL1R1 gene are thought to influence breast cancer risk. The results of the association between IL-1B, IL1R1 polymorphisms and breast cancer risk have significant. We found that the variant TT genotype of rs10490571 was associated with a significantly increased breast cancer risk (TT vs. CC: OR = 2.82, 95% CI = 1.12–7.08, P = 0.047 for the codominant model). For rs16944 (AG vs. GG: OR = 0.60, 95% CI = 0.41–0.90, P = 0.034 for the codominant model) and rs1143623 (CG vs. CC: OR = 0.65, 95% CI = 0.45–0.94, P = 0.023 for the codominant model) have significant associations were found in genetic models. In conclusion, the present analysis suggests a correlation of polymorphic markers within the IL-1 gene locus with the risk in developing breast cancer. Taken together with our finding that IL1B, IL1R1 gene three SNP are also associated with the risk for the disease, we suggest that inflammation via innate and adaptive immunity contributes to multifactorial hereditary predisposition to pathogenesis of the breast cancer.

Central Modulation of Neuroinflammation by Neuropeptides and Energy-Sensing Hormones during Obesity

Central nervous system (CNS) senses energy homeostasis by integrating both peripheral and autonomic signals and responding to them by neurotransmitters and neuropeptides release. Although it is previously considered an immunologically privileged organ, we now know that this is not so. Cells belonging to the immune system, such as B and T lymphocytes, can be recruited into the CNS to face damage or infection, in addition to possessing resident immunological cells, called microglia. In this way, positive energy balance during obesity promotes an inflammatory state in the CNS. Saturated fatty acids from the diet have been pointed out as powerful candidates to trigger immune response in peripheral system and in the CNS. However, how central immunity communicates to peripheral immune response remains to be clarified. Recently there has been a great interest in the neuropeptides, POMC derived peptides, ghrelin, and leptin, due to their capacity to suppress or induce inflammatory responses in the brain, respectively. These may be potential candidates to treat different pathologies associated with autoimmunity and inflammation. In this review, we will discuss the role of lipotoxicity associated with positive energy balance during obesity in proinflammatory response in microglia, B and T lymphocytes, and its modulation by neuropeptides.

A guinea pig model of Zika virus infection

BACKGROUND

Animal models are critical to understand disease and to develop countermeasures for the ongoing epidemic of Zika virus (ZIKV). Here we report that immunocompetent guinea pigs are susceptible to infection by a contemporary American strain of ZIKV.

METHODS

Dunkin-Hartley guinea pigs were inoculated with 10⁶ plaque-forming units of ZIKV via subcutaneous route and clinical signs were observed. Viremia, viral load in the tissues, anti-ZIKV neutralizing antibody titer, and protein levels of multiple cytokine and chemokines were analyzed using qRT-PCR, plaque assay, plaque reduction neutralization test (PRNT) and multiplex immunoassay.

RESULTS

Upon subcutaneous inoculation with PRVABC59 strain of ZIKV, guinea pigs demonstrated clinical signs of infection characterized by fever, lethargy, hunched back, ruffled fur, and decrease in mobility. ZIKV was detected in the whole blood and serum using qRT-PCR and plaque assay. Anti-ZIKV neutralizing antibody was detected in the infected animals using PRNT. ZIKV infection resulted in a dramatic increase in protein levels of multiple cytokines, chemokines and growth factors in the serum. ZIKV replication was observed in spleen and brain, with the highest viral load in the brain. This data demonstrate that after subcutaneous inoculation, the contemporary ZIKV strain is neurotropic in guinea pigs.

CONCLUSION

The guinea pig model described here recapitulates various clinical features and viral kinetics observed in ZIKV-infected patients, and therefore may serve as a model to study ZIKV pathogenesis, including pregnancy outcomes and for evaluation of vaccines and therapeutics.

Microglia activation due to obesity programs metabolic failure leading to type two diabetes

Obesity is an energy metabolism disorder that increases susceptibility to the development of metabolic diseases. Recently, it has been described that obese subjects have a phenotype of chronic inflammation in organs that are metabolically relevant for glucose homeostasis and energy. Altered expression of immune system molecules such as interleukins IL-1, IL-6, IL-18, tumor necrosis factor alpha (TNF-α), serum amyloid A (SAA), and plasminogen activator inhibitor-1 (PAI-1), among others, has been associated with the development of chronic inflammation in obesity. Chronic inflammation modulates the development of metabolic-related comorbidities like metabolic syndrome (insulin resistance, glucose tolerance, hypertension and hyperlipidemia). Recent evidence suggests that microglia activation in the central nervous system (CNS) is a priority in the deregulation of energy homeostasis and promotes increased glucose levels. This review will cover the most significant advances that explore the molecular signals during microglia activation and inflammatory stage in the brain in the context of obesity, and its influence on the development of metabolic syndrome and type two diabetes.

Identification of host genes leading to West Nile virus encephalitis in mice brain using RNA-seq analysis

Differential host responses may be critical determinants of distinct pathologies of West Nile virus (WNV) NY99 (pathogenic) and WNV Eg101 (non-pathogenic) strains. We employed RNA-seq technology to analyze global differential gene expression in WNV-infected mice brain and to identify the host cellular factors leading to lethal encephalitis. We identified 1,400 and 278 transcripts, which were differentially expressed after WNV NY99 and WNV Eg101 infections, respectively, and 147 genes were common to infection with both the viruses. Genes that were up-regulated in infection with both the viruses were mainly associated with interferon signaling. Genes associated with inflammation and cell death/apoptosis were only expressed after WNV NY99 infection. We demonstrate that differences in the activation of key pattern recognition receptors resulted in the induction of unique innate immune profiles, which corresponded with the induction of interferon and inflammatory responses. Pathway analysis of differentially expressed genes indicated that after WNV NY99 infection, TREM-1 mediated activation of toll-like receptors leads to the high inflammatory response. In conclusion, we have identified both common and specific responses to WNV NY99 and WNV Eg101 infections as well as genes linked to potential resistance to infection that may be targets for therapeutics.

Diabetes and infection: assessing the association with glycaemic control in population-based studies

Diabetes is a leading cause of morbidity and mortality. The global burden of diabetes is rising because of increased obesity and population ageing. Although preventive and treatment measures are well documented for macrovascular and microvascular complications, little such guidance exists for infections in people with diabetes, despite evidence suggesting greater susceptibility to infections, and worse outcomes. In particular, few studies have characterised the relation between glycaemic control and infectious disease, which we discuss in this Review. Some large population-based observational studies have reported strong associations between higher HbA1c and infection risks for both type 1 and type 2 diabetes. However, studies are contradictory, underpowered, or do not control for confounders. Evidence suggests that better glycaemic control might reduce infection risk, but further longitudinal studies with more frequent measures of HbA1c are needed. Older people (aged 70 years or older) with diabetes are at increased risk of complications, including infectious diseases. There is more uncertainty about appropriate glycaemic control targets in this age group, and evidence suggests that glycaemic control is often neglected. Robust evidence from cohorts with sufficient numbers of older people would help to develop clinically relevant guidelines and targets to reduce mortality, morbidity, and antibiotic use, and to improve quality of life.

Examination of West Nile Virus Neuroinvasion and Neuropathogenesis in the Central Nervous System of a Murine Model

West Nile virus (WNV) is a neurotropic virus that causes inflammation and neuronal loss in the Central Nervous System leading to encephalitis and death. In this chapter, detailed methods to detect WNV in the murine brain tissue by quantitative real-time polymerase chain reaction and viral plaque assays are described. Determination of WNV neuropathogenesis by Hematoxylin and Eosin staining and immunohistochemical procedures are provided. In addition, TUNEL assays to determine neuronal loss during WNV neuropathogenesis are discussed in detail. Collectively, the methods mentioned in this chapter provide an overview to understand neuroinvasion and neuropathogenesis in a murine model of WNV infection.

Induction of virus-specific effector immune cell response limits virus replication and severe disease in mice infected with non-lethal West Nile virus Eg101 strain

Background

West Nile virus (WNV) is a neurotropic flavivirus that has emerged globally as a significant cause of viral encephalitis in humans. Herein, we investigated the immunological responses induced by two phylogenetically related WNV strains of lineage 1, WNV NY99, and WNV Eg101.

Methods

Eight-week-old C57BL/6J mice were inoculated with WNV NY99 or WNV Eg101 and mortality, virus burden in the periphery and brain, type 1 interferon response, WNV-specific antibodies, leukocyte infiltration, and inflammatory responses were analyzed.

Results

As expected, WNV NY99 infected mice demonstrated high morbidity and mortality, whereas no morbidity and mortality was observed in WNV Eg101 infected mice. Virus titers were comparable in the serum of both WNV NY99 and WNV Eg101 infected mice at day 3 after inoculation; however, at day 6, the virus was cleared from WNV Eg101 infected mice but the virus titer remained high in the WNV NY99 infected mice. Virus was detected in the brains of both WNV NY99 and Eg101 infected mice, albeit significantly higher in the brains of WNV NY99 infected mice. Surprisingly, levels of type 1 interferon and WNV-specific antibodies were significantly higher in the serum and brains of WNV NY99 infected mice. Similarly, protein levels of multiple cytokines and chemokines were significantly higher in the serum and brains of WNV NY99 infected mice. In contrast, we observed significantly higher numbers of innate and adaptive immune cells in the spleens and brains of WNV Eg101 infected mice. Moreover, total number and percentage of IFN-γ and TNF-α producing WNV-specific CD8⁺ T cells were also significantly high in WNV Eg101 infected mice.

Conclusions

Our data demonstrate that induction of virus-specific effector immune cell response limits virus replication and severe WNV disease in Eg101 infected mice. Our data also demonstrate an inverse correlation between leukocyte accumulation and production of pro-inflammatory mediators in WNV-infected mice. Moreover, increased production of pro-inflammatory mediators was associated with high-virus titers and increased mortality in WNV NY99 infected mice.

Of Mice and Men: Protective and Pathogenic Immune Responses to West Nile virus Infection

West Nile virus, a mosquito-borne flavivirus, first emerged in the Western Hemisphere in 1999. Although the majority of infections are asymptomatic, WNV causes significant morbidity and mortality in a minority of individuals who develop neuroinvasive disease, in particular the elderly and immunocompromised. Research in animal models has demonstrated interactions between WNV and the innate and adaptive immune system, some of which protect the host and others which are deleterious. Studies of disease pathogenesis in humans are less numerous, largely due to the complexities of WNV epidemiology. Human studies that have been done support the notion that innate and adaptive immune responses are delicately balanced and may help or harm the host. Further human investigations are needed to characterize beneficial responses to WNV with the goal of such research leading to therapeutics and effective vaccines in order to control this emerging viral disease.