Current Protein and Peptide Science - Volume 23, Issue 2, 2022

Glucagon-Like Peptide-2 (GLP-2) is a pleiotropic hormone that plays several roles in different organs and tissues, so being involved in many physiological processes. Among these, it regulates gastrointestinal (GI) tract function binding to a specific G-protein coupled receptor (GLP-2R). Of note, GLP-2R is widely expressed in different cells of the GI tract, including excitatory and inhibitory neurons of the enteric nervous system. In the gut, GLP-2 has been reported to play numerous actions, among which the modulation of motility. Nevertheless, most of the GLP-2 effects and its role in physiological processes are still debated. The aim of this minireview is to summarize the data present in the literature on the control of GI motility by GLP-2, the mechanism through which it occurs, and to discuss the physiological implications of such effects. A better understanding of the role of GLP-2 on GI motor responses may be of importance for the development of new therapeutic approaches in GI dysmotility.

The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), has swept the whole world and brought about public health crisis of unprecedented proportions. In the process of SARS-CoV-2 entry, angiotensin-converting enzyme 2 plays a key role. In addition, other protein molecules, such as transmembrane protease/serine 2, FURIN, Cathepsin L, and a disintegrin and metalloproteinase 17 will also affect the interaction between virus and host cells. Since the variations in the virus and human populations could determine the transmissibility of the virus and influence an individual’s susceptibility to SARS-CoV-2 infection and disease outcome, research on the variations of the above protein molecules and their role in COVID-19 is in full swing. In this review, we systematically reviewed viral and host genetic variations related to SARSCoV- 2 entry, as well as the relationship between the diversity of these variations and the COVID-19 pandemic. We aim to provide better insights into the transmission and pathogenesis of COVID-19 from the perspective of genetic variants and epigenetic factors so as to prevent, control, and treat COVID-19, especially among high-risk populations with genetic risk variants.

The high stability of phosphodiester bonds is considered to be one of the important reasons for the genetic role of nucleic acids, and their cleavage is also the core of many key biochemical processes, including DNA replication/ repair, and RNA processing/ degradation. As an important part of the base excision repair (BER) pathway, human apurinic/ apyrimidinic endonuclease 1 (APE1) is indispensable for the repair of abasic sites and other DNA damage, including ionizing radiation, DNA covalently bonding induced by cytotoxic antitumor drugs, etc. For tumor cells, the DNA repair activity of APE1 may lead to the occurrence of radiotherapy and chemotherapy resistance. The overexpression of APE1 often poses a serious threat to the effectiveness of tumor treatment, indicating a longer time, a much larger dose, less effective chemotherapy, and poor prognosis. It is of great urgency to design novel APE1 inhibitors. Rational design and modification of inhibitor molecules are closely related to the research progress of both structural biology and catalytic mechanism. In this review, the structure, catalytic mechanism, inhibitors, and other important biochemical information regarding APE1 are summarized, which will help in the design and modification of drug molecules targeting APE1.

Physical exercise is a therapeutic strategy for some systemic and non-systemic complications. Various processes or factors like myokines are involved in an exercise course. Irisin is produced in skeletal muscle during exercise, and its effects resemble many exercise effects. Besides the systemic effects of muscle-derived irisin, this peptide is produced in different tissues. Numerous studies have investigated the underlying molecular mechanisms of irisin effects. Despite some controversies, most studies have demonstrated the improvement of metabolic-related complications and immunomodulatory or regenerative mechanisms in correlation with the circulating level of this peptide or after in vivo/in vitro treatments that have introduced it as a peptide with therapeutic value. This review describes the similarities and differences of the effects in various tissues and their correlation with the most prevalent tissue-related complication to present a view for the mechanism(s) of function, efficacy, and safety of this peptide in each tissue as an exercise effector and endocrine peptide.

The life cycle of the Herpes simplex virus starts with attachment to the host cell, injection of the nucleocapsid into the cytoplasm, replication, transcription and viral protein production, and finally, the assembly of the mature virion nucleopcapsid. The assembled nucleocapsid exits the host nucleus and gains a tegument layer bound within a bilayer of membrane phospholipid. The packaged virion particle then exits the host cell. The interaction of the (Deoxyribonucleic acid) DNA packaging complex- terminase, present on the mature viral nucleocapsid, with other proteins involved in nuclear egress and cytoplasmic tegumentation has led to the proposal of the model by which the terminase complex may be involved in these two events. The role of terminase complex in Herpes Simplex Virus (HSV) genomic DNA encapsidation into the capsid is previously established, but the role of the terminase subunits post DNA packaging remains unclear. The current review provides a model by which the terminase complex may have a role to play in the events of nuclear egress and secondary envelopment.

Post-translational modifications (PTMs) may affect the functions of human serum albumin. Here we review reports of novel PTMs of human serum albumin. This study reviewed one hundred twenty-three recently reported novel O-phosphorylation, glycation, methylation, carbonylation, and acetylation of albumin. Furthermore, the potential impact of these PTMs on albumin functions is discussed. Knowledge of these PTMs of albumin is important for the use of albumin in medical applications, e.g., in transfusion, drug formulations, and remedies.

Background: Nucleotide-binding oligomerization domain-containing protein 1 (NOD1) is known to play an important role in innate immunity, while the relationship between NOD1 and inflammatory response in endometriosis remains unknown. The present study aims to investigate the effects of NOD1 on inflammatory response in endometriosis. Methods: Immunohistochemistry staining, Western blot, and qRT-PCR were conducted to investigate the levels of NOD1 and inflammatory cytokines in the endometriotic lesions. A Spearman’s rank correlation analysis was conducted to determine the correlations of NOD1 and inflammatory cytokines (interleukin (IL)-6, tumor necrosis factor (TNF)-α, and monocyte chemoattractant protein (MCP)-1). Human endometrial stromal cells (HESCs) were isolated and incubated with peritoneal fluid with or without ML130. Cell viability was determined by using an MTT assay. Results: A significant elevation in NOD1 and inflammatory cytokine was observed in ectopic endometrium. Interestingly, a positive correlation between NOD1 and inflammatory cytokines was observed. In addition, treatment with ML130 significantly suppressed cell viability and the production of inflammatory cytokines in the 20% peritoneal fluid treated ectopic HESCs. Conclusions: NOD1 is related to the inflammatory response that is involved in endometriosis.