Bat Red Blood Cells express Nucleic Acid Sensing Receptors and bind RNA and DNA

Red blood cells (RBCs) demonstrate immunomodulatory capabilities through the expression of nucleic acid sensors. Little is known about bat RBCs, and no studies have examined the immune function of bat erythrocytes. Here we show that bat RBCs express the nucleic acid-sensing Toll-like receptors TLR7 and TLR9 and bind the nucleic acid ligands, single-stranded RNA, and CpG DNA. Collectively, these data suggest that, like human RBCs, bat erythrocytes possess immune function and may be reservoirs for nucleic acids. These findings provide unique insight into bat immunity and may uncover potential mechanisms by which virulent pathogens in humans are concealed in bats.

The Significance of Toll-Like Receptors in the Neuroimmunologic Background of Alcohol Dependence

Toll-like receptors (TLR) are a group of protein belonging to the family of Pattern Recognition Receptors (PRR) which have the ability to distinguish between an organism's own antigens and foreign ones and to induce immunological response. TLR play a significant part in non-specific immunity but at the same time they are also a vital element linking non-specific response to the specific one. A growing number of data seems to indicate that the non-specific immunity mechanisms affect the development and sustenance of alcohol addiction. Alcohol damages the organism's cells not only directly but also through an increase inintestinal permeability which induces innate immune response of peripheral blood cells. The signaling pathway of Toll-like receptors located on the surface of brain immune cells intensifies the inflammatory reaction and, through modifying gene expression of proinflammatory factors, unnaturally supports it. This overly protracted “sterile inflammatory reaction” positively correlates with alcohol craving affecting also the functioning of the reward system structures and increasing the risk of relapse of alcoholism. Recurrent alcoholic binges sensitize the microglia and cause an escalation in inflammatory reaction which also leads to neurodegeneration. The induction of innate immunity signaling pathways exposes clinical symptoms of alcohol addiction such as increased impulsivity, loss of behavioral control, depressive-anxiety symptoms and cognitive dysfunctions. Traditional methods of treating alcohol addiction have tended to focus predominantly on reducing symptoms which—given the frequency of relapses—seems insufficient. The aim of the present paper is to discuss the role of toll-like receptors as elements of the immunity system which, together with the nervous system, plays a crucial part in the pathogenesis of alcohol addiction. We also wish to present pharmacotherapeutic perspectives targeted at the neuroimmunological mechanisms of alcohol addiction.

The microRNA days: The COVID-19 pandemic from the point of view of short RNAs

Despite their biological simplicity, microRNA-based organisms, such as RNA viruses, are currently shown to be unexpected threats to mammals, including humans. This situation is exemplified by the COVID-19 pandemic triggered by the spread of SARS-CoV-2. RNA viruses are older than DNA viruses. Indeed, from an evolutionary standpoint, RNA is an older molecule than DNA. The strength of RNA viruses, compared to DNA viruses, resides in their simplicity and instability. The instability of RNA viruses, such as human immunodeficiency virus (HIV) and flu viruses, generates mutants to escape the host’s defense mechanisms. A formidable combination of lethality and infectivity was recently achieved by SARS-CoV-2. Complex DNAbased defense systems use Toll-like receptors to intercept viral RNA inside a cell. Activation of Toll-like receptors triggers inflammation and activates lymphocytes and monocytes, causing thromboxane release. In the case of SARS-CoV-2 infection, this process results in cytokine storms and lung thromboembolism. The ongoing pandemic can be envisioned as a struggle between highly evolved complex DNA organisms, i.e., humans, and poorly evolved simple RNA organisms, i.e., SARS-CoV-2 virus. Quite surprisingly, the complex organism has a serious problem defeating the simplistic organism. However, humans are finally developing a new effective weapon in fighting the SARS-CoV-2 virus, paradoxically, RNA-based vaccines. These considerations underscore the relevance of microRNAs as powerful tools in therapeutic and preventive medicine.