Chitotriosidase Activity Is Counterproductive in a Mouse Model of Systemic Candidiasis

The Exploitation of the Glycosylation Pattern in Asthma: How We Alter Ancestral Pathways to Develop New Treatments

Asthma has reached epidemic levels, yet progress in developing specific therapies is slow. One of the main reasons for this is the fact that asthma is an umbrella term for various distinct subsets. Due to its high heterogeneity, it is difficult to establish biomarkers for each subset of asthma and to propose endotype-specific treatments. This review focuses on protein glycosylation as a process activated in asthma and ways to utilize it to develop novel biomarkers and treatments. We discuss known and relevant glycoproteins whose functions control disease development. The key role of glycoproteins in processes integral to asthma, such as inflammation, tissue remodeling, and repair, justifies our interest and research in the field of glycobiology. Altering the glycosylation states of proteins contributing to asthma can change the pathological processes that we previously failed to inhibit. Special emphasis is placed on chitotriosidase 1 (CHIT1), an enzyme capable of modifying LacNAc- and LacdiNAc-containing glycans. The expression and activity of CHIT1 are induced in human diseased lungs, and its pathological role has been demonstrated by both genetic and pharmacological approaches. We propose that studying the glycosylation pattern and enzymes involved in glycosylation in asthma can help in patient stratification and in developing personalized treatment.

Chitinases and chitinase-like proteins in asthma

Despite the lack of endogenous chitin synthesis, mammalian genomes encode two enzymatically active true chitinases (chitotriosidase and acidic mammalian chitinase) and a variable number of chitinase-like proteins (CLPs) that have no enzyme activity but bind chitin. Chitinases and CLPs are prominent components of type-2 immune response-mediated respiratory diseases. However, despite extensive research into their role in allergic airway disease, there is still no agreement on whether they are mere biomarkers of disease or actual disease drivers. Functions ascribed to chitinases and CLPs include, but are not limited to host defense against chitin-containing pathogens, directly promoting inflammation, and modulating tissue remodeling and fibrosis. Here, we discuss in detail the chitin-dependent and -independent roles of chitinases and CLPs in the context of allergic airway disease, and recent advances and emerging concepts in the field that might identify opportunities for new therapies.

Evaluation of Circulating Chitotriosidase Activity in Children with Obesity

Childhood obesity progresses to metabolic disturbances via low-grade inflammation. Identifying novel molecules that reflect the activity of the immune responses is critical in understanding its underlying pathogenesis. Our exploratory study aimed to evaluate the change of chitotriosidase (CHIT1) plasma activity according to Body Mass Index (BMI)-for-age z score in pediatric patients. The study evaluated 68 children consisting of 47.1% girls with a mean age of 12.47 ± 3.71 years and 52.9% boys with a mean age of 11.93 ± 3.18 years. The effect of the most frequent CHIT1 gene variants, the 24 base pair duplication (dup24) and G102S polymorphism, upon the association between circulating CHIT1 activity and the obesity level, was also investigated. A significantly higher logCHIT1 plasma activity was found in children with extreme obesity than in children with overweight (p = 0.048 for the uncorrected CHIT1 and 0.026 for the corrected CHIT1). The BMI-for-age z score significantly (p = 0.031) predicts increased CHIT1 activity in children with overweight, obesity, and extreme obesity after controlling for the two gene variants, age, gender, and time since weight gain. Dup24 and G102S polymorphism were significant independent predictors (p-values < 0.002) for the change of CHIT1 plasma activity. Circulating CHIT1 might be an accurate indicator of inflammation in children with obesity. Its role and the effect of the dup24 and G102S variants on the CHIT1 activity should be validated in a larger cohort.