Curb complement to cure COVID-19

Intertwined pathways of complement activation command the pathogenesis of lupus nephritis

The complement system is involved in the origin of autoimmunity and systemic lupus erythematosus. Both genetic deficiency of complement components and excessive activation are involved in primary and secondary renal diseases, including lupus nephritis. Among the pathways, the classical pathway has long been accepted as the main pathway of complement activation in systemic lupus erythematosus. However, more recent studies have shown the contribution of factors B and D which implies the involvement of the alternative pathway. While there is evidence on the role of the lectin pathway in systemic lupus erythematosus, it is yet to be demonstrated whether this pathway is protective or harmful in lupus nephritis. Complement is being explored for the development of disease biomarkers and therapeutic targeting. In the current review we discuss the involvement of complement in lupus nephritis.

Non-invasive diagnostic potential of microRNA-203 in liquid biopsy of urothelial carcinoma of bladder

Increased CD44 antigen activity has been reported in recurrent cases of UBC. To date, no reliable biomarker is available with high significance and specificity for non-invasive detection of UBC. This study aimed to identify a CD44-linked microRNAs (miRNAs) (miR-9, miR-34a, miR-203) for non-invasive diagnosis of bladder cancer from other urinary tract malignancies. The expression of CD44-linked miRNAs was examined in serum, urine, and tissue specimens of Indian UBC patients (N = 25). For this purpose, healthy subjects (N = 25) and benign prostatic hyperplasia (BPH) (N = 10) patients were taken as controls. The relative expression of miRNAs was analyzed in serum, urine, and tissue samples using real-time quantitative reverse transcription PCR (qRT-PCR). The diagnostic potential of these miRNAs was accessed by plotting ROC curve. Increased miR-9 expression was observed in serum of UBC patients than healthy and BPH controls. In UBC patients, miR-34a expression was lower than healthy controls but non-significant as compared to BPH. miR-203 expression was considerably higher in serum of UBC patients but non-significant as compared to BPH controls. miR-203 was found to be considerably higher in urine samples from UBC patients as compared to BPH and healthy controls. The diagnostic potential of these miRNAs was evaluated using the ROC curve. Higher miR-203 levels in the urine of Indian UBC patients demonstrate its non-invasive diagnostic ability out of the three miRNAs studied. Our results characterize the non-invasive diagnostic potential of CD44-linked miR-203 in the urine of Indian UBC patients, which could be utilized in clinical settings in future after validation in larger patient cohort.

Autophagy-associated HMGB-1 as a novel potential circulating non-invasive diagnostic marker for detection of Urothelial Carcinoma of Bladder

Urothelial carcinoma of bladder (UBC), a highly prevalent urological malignancy associated with high mortality and recurrence rate. Standard diagnostic method currently being used is cystoscopy but its invasive nature and low sensitivity stresses for identifying predictive diagnostic marker. Autophagy, a cellular homeostasis maintaining process, is usually dysregulated in cancer and its role is still enigmatic in UBC. In this study, 30 UBC patients and healthy controls were enrolled. Histopathologically confirmed tumor and adjacent normal tissue were acquired from patients. Molecular expression and tissue localization of autophagy-associated molecules (HMGB-1, RAGE, beclin, LC-3, and p62) were investigated. Serum HMGB-1 concentration was measured in UBC patients and healthy controls. ROC curves were plotted to evaluate diagnostic potential. Transcript, protein, and IHC expression of HMGB-1, RAGE, beclin, and LC-3 displayed upregulated expression, while p62 was downregulated in bladder tumor tissue. Serum HMGB-1 levels were elevated in UBC patients. Transcript and circulatory levels of HMGB-1 showed positive correlation and displayed a positive trend with disease severity. Upon comparison with clinicopathological parameters, HMGB-1 emerged as molecule of statistical significance to exhibit association. HMGB-1 exhibited optimum sensitivity and specificity in serum. The positive correlation between tissue and serum levels of HMGB-1 showcases serum as a representation of in situ scenario, suggesting its clinical applicability for non-invasive testing. Moreover, optimum sensitivity and specificity displayed by HMGB-1 along with significant association with clinicopathological parameters makes it a potential candidate to be used as diagnostic marker for early detection of UBC but requires further validation in larger cohort.

BTK inhibitors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): A systematic review

Introduction

The Bruton tyrosine kinase (BTK) regulates B cell and macrophage signaling, development, survival, and activation. Inhibiting BTK has been hypothesized to ameliorate lung injury in patients with severe COVID-19, however clinical outcome data is inconclusive.

Objective

To evaluate the clinical outcomes of BTK inhibitors (BTKinibs) in patients with COVID-19.

Evidence review

We searched PubMed, Embase, and Web of Science:Core on December 30, 2020. Clinical studies with at least 5 COVID-19 patients treated with BTKinibs were included. Case reports and reviews were excluded.

Findings

125 articles were identified, 6 of which met inclusion criteria. The most common clinical outcomes measured were oxygen requirements (4/6) and hospitalization rate or duration (3/6). Three studies showed decreased oxygen requirements in patients who started or continued BTKinibs. All three studies that evaluated hospitalization rate or duration found favorable outcomes in those on BTKinibs.

Conclusions and relevance

BTKinib use was associated with decreased oxygen requirements and decreased hospitalization rates and duration.

Exosomal DNMT1 mRNA transcript is elevated in acute lymphoblastic leukemia which might reprograms leukemia progression

DNMT1 (DNA-methyltransferase 1) is an enzyme which contributes to the process of normal embryonic development, and aberrant expression of DNMT1 leads to tumor/leukemia progression by inducing significant changes in DNA methylation and epigenetics. We found that DNMT1 mRNA transcript is elevated in Exo-PALL compared to Exo-HD. We also confirmed and showed heightened levels of DNMT1 mRNA transcript in Exo-CM of leukemia cell lines. Co-culture of Exo-PALL with target cells (leukemia B cells) showed transfer of exosomal DNMT1 mRNA transcript into the target cells, which may reprogram the biological nature of normal healthy cells and leukemia cells.

The Role of High-Density Lipoprotein in COVID-19

The current Coronavirus disease 2019 (COVID-19) pandemic has become a global challenge. Managing a large number of acutely ill patients in a short time, whilst reducing the fatality rate and dealing with complications, brings unique difficulties. The most striking pathophysiological features of patients with severe COVID-19 are dysregulated immune responses and abnormal coagulation function, which can result in multiple-organ failure and death. Normally metabolized high-density lipoprotein (HDL) performs several functions, including reverse cholesterol transport, direct binding to lipopolysaccharide (LPS) to neutralize LPS activity, regulation of inflammatory response, anti-thrombotic effects, antioxidant, and anti-apoptotic properties. Clinical data shows that significantly decreased HDL levels in patients with COVID-19 are correlated with both disease severity and mortality. However, the role of HDL in COVID-19 and its specific mechanism remain unclear. In this analysis, we review current evidence mainly in the following areas: firstly, the pathophysiological characteristics of COVID-19, secondly, the pleiotropic properties of HDL, thirdly, the changes and clinical significance of HDL in COVID-19, and fourthly the prospect of HDL-targeting therapy in COVID-19 to clarify the role of HDL in the pathogenesis of COVID-19 and discuss the potential of HDL therapy in COVID-19.

Complement activation and increased expression of Syk, mucin-1 and CaMK4 in kidneys of patients with COVID-19

Acute and chronic kidney failure is common in hospitalized patients with COVID-19, yet the mechanism of injury and predisposing factors remain poorly understood. We investigated the role of complement activation by determining the levels of deposited complement components (C1q, C3, FH, C5b-9) and immunoglobulin along with the expression levels of the injury-associated molecules spleen tyrosine kinase (Syk), mucin-1 (MUC1) and calcium/calmodulin-dependent protein kinase IV (CaMK4) in the kidney tissues of people who succumbed to COVID-19. We report increased deposition of C1q, C3, C5b-9, total immunoglobulin, and high expression levels of Syk, MUC1 and CaMK4 in the kidneys of COVID-19 patients. Our study provides strong rationale for the expansion of trials involving the use of inhibitors of these molecules, in particular C1q, C3, Syk, MUC1 and CaMK4 to treat patients with COVID-19.

Activation of classical and alternative complement pathways in the pathogenesis of lung injury in COVID-19

Lung inflammation and damage is prominent in people infected with SARS-Cov-2 and a major determinant of morbidity and mortality. We report the deposition of complement components in the lungs of people who succumbed to COVID-19 consistent with the activation of the classical and the alternative pathways. Our study provides strong rationale for the expansion of trials involving the use of complement inhibitors to treat patients with COVID-19.

Genetic justification of severe COVID-19 using a rigorous algorithm

Recent studies suggest excessive complement activation in severe coronavirus disease-19 (COVID-19). The latter shares common characteristics with complement-mediated thrombotic microangiopathy (TMA). We hypothesized that genetic susceptibility would be evident in patients with severe COVID-19 (similar to TMA) and associated with disease severity. We analyzed genetic and clinical data from 97 patients hospitalized for COVID-19. Through targeted next-generation-sequencing we found an ADAMTS13 variant in 49 patients, along with two risk factor variants (C3, 21 patients; CFH,34 patients). 31 (32%) patients had a combination of these, which was independently associated with ICU hospitalization (p = 0.022). Analysis of almost infinite variant combinations showed that patients with rs1042580 in thrombomodulin and without rs800292 in complement factor H did not require ICU hospitalization. We also observed gender differences in ADAMTS13 and complement-related variants. In light of encouraging results by complement inhibitors, our study highlights a patient population that might benefit from early initiation of specific treatment.

Putative roles of vitamin D in modulating immune response and immunopathology associated with COVID-19

The first incidence of COVID-19 was reported in the Wuhan city of Hubei province in China in late December 2019. Because of failure in timely closing of borders of the affected region, COVID-19 spread across like a wildfire through air travel initiating a pandemic. It is a serious lower respiratory track viral infection caused by highly contagious, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Coronavirus including COVID-19 causing SARS-CoV-2 causes zoonotic diseases and thought to be originated from bats. Since its first incidence, the virus has spread all across the world, causing serious human casualties, economic losses, and disrupting global supply chains. As with SARS-CoV, COVID-19 causing SARS-CoV-2 follows a similar path of airborne infection, but is less lethal and more infectious than SARS and MERS. This review focusses on the pathogenesis of SARS-CoV-2, especially on the dysfunctional immune responses following a cytokine storm in severely affected persons. The mode of entry of SARS-CoV-2 is via the angiotensin converting enzyme 2 (ACE-2) receptors present on the epithelial lining of lungs, gastrointestinal tract, and mucus membranes. Older persons with weaker immune system and associated co-morbidities are more vulnerable to have dysfunctional immune responses, as most of them concomitantly have severe hypovitaminosis D. Consequently, causing severe damage to key organs of the body including lungs and the cardiovascular system. Since, vast majority of persons enters to the intensive care units and died, had severe vitamin D deficiency, thus, this area must be investigated seriously. In addition, this article assesses the role of vitamin D in reducing the risk of COVID-19. Vitamin D is a key regulator of the renin-angiotensin system that is exploited by SARS-CoV-2 for entry into the host cells. Further, vitamin D modulates multiple mechanisms of the immune system to contain the virus that includes dampening the entry and replication of SARS-CoV-2, reduces concentration of pro-inflammatory cytokines and increases levels of anti-inflammatory cytokines, enhances the production of natural antimicrobial peptide and activates defensive cells such as macrophages that could destroy SARS-CoV-2. Thus, this article provides the urgency of needed evidences through large population based randomized controlled trials and ecological studies to evaluate the potential role of vitamin D in COVID-19.

Review on COVID-19 Etiopathogenesis, Clinical Presentation and Treatment Available with Emphasis on ACE2

In December 2019, Wuhan city in the Hubei province of China reported for the first time a cluster of patients infected with a novel coronavirus, since then there has been an outburst of this disease across the globe affecting millions of human inhabitants. Severe acute respiratory syndrome coronavirus type-2 (SARS-CoV-2), is a member of beta coronavirus family which upon exposure caused a highly infectious disease called novel coronavirus disease-2019 (COVID-19). COVID-19, a probably bat originated disease was declared by World Health Organization (WHO) as a global pandemic in March 2020. Since then, despite rigorous global containment and quarantine efforts, the disease has affected nearly 56,261,952 laboratory confirmed human population and caused deaths of over 1,349,506 lives worldwide. Virus passes in majority through respiratory droplets and then enters lung epithelial cells by binding to angiotensin converting enzyme 2 (ACE2) receptor and there it undergoes replication and targeting host cells causing severe pathogenesis. Majority of human population exposed to SARS-CoV-2 having fully functional immune system undergo asymptomatic infection while 5-10% are symptomatic and only 1-2% are critically affected and requires ventilation support. Older people or people with co-morbidities are severely affected by COVID-19. These categories of patients also display cytokine storm due to dysfunctional immune response which brutally destroys the affected organs and may lead to death in some. Real time PCR is still considered as standard method of diagnosis along with other serology, radiological and biochemical investigations. Till date, no specific validated medication is available for the treatment of COVID-19 patients. Thus, this review provides detailed knowledge about the different landscapes of disease incidence, etiopathogenesis, involvement of various organs, diagnostic criteria's and treatment guidelines followed for management of COVID-19 infection since its inception. In conclusion, extensive research to recognize novel pathways and their cross talk to combat this virus in precarious settings is our future positive hope.