The Role of Adipokines in the Pathologies of the Central Nervous System

Adipokines are protein hormones secreted by adipose tissue in response to disruptions in physiological homeostasis within the body's systems. The regulatory functions of adipokines within the central nervous system (CNS) are multifaceted and intricate, and they have been identified in a number of pathologies. Therefore, specific adipokines have the potential to be used as biomarkers for screening purposes in neurological dysfunctions. The systematic review presented herein focuses on the analysis of the functions of various adipokines in the pathogenesis of CNS diseases. Thirteen proteins were selected for analysis through scientific databases. It was found that these proteins can be identified within the cerebrospinal fluid either by their ability to modify their molecular complex and cross the blood-brain barrier or by being endogenously produced within the CNS itself. As a result, this can correlate with their measurability during pathological processes, including Alzheimer's disease, amyotrophic lateral sclerosis, multiple sclerosis, depression, or brain tumors.

Monocyte-Derived Macrophages Contribute to Chitinase Dysregulation in Amyotrophic Lateral Sclerosis: A Pilot Study

Neuroinflammation significantly contributes to Amyotrophic Lateral Sclerosis (ALS) pathology. In lieu of this, reports of elevated chitinase levels in ALS are interesting, as they are established surrogate markers of a chronic inflammatory response. While post-mortem studies have indicated glial expression, the cellular sources for these moieties remain to be fully understood. Therefore, the objective of this pilot study was to examine whether the peripheral immune system also contributes to chitinase dysregulation in ALS. The temporal expression of CHIT1, CHI3L1, and CHI3L2 in non-polarized monocyte-derived macrophages (MoMas) from ALS patients and healthy controls (HCs) was examined. We demonstrate that while CHIT1 and CHI3L1 display similar temporal expression dynamics in both groups, profound between-group differences were noted for these targets at later time-points i.e., when cells were fully differentiated. CHIT1 and CHI3L1 expression were significantly higher in MoMas from ALS patients at both the transcriptomic and protein level, with CHI3L1 levels also being influenced by age. Conversely, CHI3L2 expression was not influenced by disease state, culture duration, or age. Here, we demonstrate for the first time, that in ALS, circulating immune cells have an intrinsically augmented potential for chitinase production that may propagate chronic neuroinflammation, and how the ageing immune system itself contributes to neurodegeneration.

NOD2 expression, DNA damage and oxido-inflammatory status in atopic bronchial asthma: Exploring their nexus to disease severity

BACKGROUND

Allergic asthma is a chronically relapsing inflammatory airway disease with a complex pathophysiology.

AIM

This study was undertaken to investigate the potential contribution of NOD2 signaling, proinflammatory cytokines, chitotriosidase (CHIT1) activity, oxidative stress and DNA damage to atopic asthma pathogenesis, as well as to explore their possible role as surrogate noninvasive biomarkers for monitoring asthma severity.

METHODS

Sixty patients with atopic bronchial asthma who were divided according to asthma severity into 40 mild-moderate, 20 severe atopic asthmatics, in addition to thirty age-matched healthy controls were enrolled in this study. NOD2 expression in PBMCs was assessed by quantitative real-time RT-PCR. DNA damage indices were assessed by alkaline comet assay. Serum IgE, IL-17, IL-8 and 3-Nitrotyrosine levels were estimated by ELISA. Serum CHIT1and GST activities, as well as MDA levels, were measured.

RESULTS

NOD2 mRNA relative expression levels were significantly decreased in atopic asthmatic cases relative to controls with lower values among severe atopic asthmatics. On the other hand, IL-17 and IL-8 serum levels, CHIT1 activity, DNA damage indices and oxidative stress markers were significantly increased in atopic asthmatic cases relative to controls with higher values among severe atopic asthmatics. The change in these parameters correlated significantly with the degree of decline in lung function.

CONCLUSION

The interplay between NOD2 signaling, proinflammatory cytokines, CHIT1 activity, heightened oxidative stress and DNA damage orchestrates allergic airway inflammation and thus contributing to the pathogenesis of atopic asthma. These parameters qualified for measurement as part of new noninvasive biomarker panels for monitoring asthma severity.

New insights on chitinases immunologic activities

Mammalian chitinases and the related chilectins (ChiLs) belong to the GH18 family, which hydrolyse the glycosidic bond of chitin by a substrate-assisted mechanism. Chitin the fundamental component in the coating of numerous living species is the most abundant natural biopolymer. Mounting evidence suggest that the function of the majority of the mammalian chitinases is not exclusive to catalyze the hydrolysis of chitin producing pathogens, but include crucial role specific in the immunologic activities. The chitinases and chitinase-like proteins are expressed in response to different proinflammatory cues in various tissues by activated macrophages, neutrophils and in different monocyte-derived cell lines. The mechanism and molecular interaction of chitinases in relation to immune regulation embrace bacterial infection, inflammation, dismetabolic and degenerative disease. The aim of this review is to update the reader with regard to the role of chitinases proposed in the recent innate and adaptive immunity literature. The deep scrutiny of this family of enzymes could be a useful base for further studies addressed to the development of potential procedure directing these molecules as diagnostic and prognostic markers for numerous immune and inflammatory diseases.

Chitinases and immunity: Ancestral molecules with new functions

Chitinases belonging to 18 glycosyl hydrolase family is an ancient gene family that is widely expressed from prokaryotes to eukaryotes. In humans, despite the absence of endogenous chitin, a number of Chitinases and Chitinase-like Proteins (C/CLPs) have been identified. Chitinases with enzymatic activity have a chitin binding domain containing six cysteine residues responsible for their binding to chitin. In contrast, CLPs do not contain such typical chitin-binding domains, but still can bind to chitin with high affinity. Molecular phylogenetic analyses suggest that active Chitinases result from an early gene duplication event. Further duplication events, followed by mutations leading to loss of chitinase activity, allowed evolution of the chi-lectins. For the majority of the mammalian chitinases the last decades have witnessed the appearance of a substantial number of studies describing their expression differentially regulated during more specific immunologic activities. It is becoming increasingly clear that their function is not exclusive to catalyse the hydrolysis of chitin producing pathogens, but include crucial role in bacterial infections and inflammatory diseases. Here we provide an overview of all family members to shed light on the mechanisms and molecular interactions of Chitinases and CLPs in relation to immune response regulation, in order to delineate their future utilization as diagnostic and prognostic markers for numerous diseases.