Current Molecular Medicine - Volume 22, Issue 6, 2022

Overwhelming responses are seen at preclinical and clinical levels to understand and combat coronavirus disease 2019 [COVID-19] pandemic that is caused by severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]. Encouraging successes are achieved in view of diagnostic, therapeutic and preventive measures, including vaccines development. In fact, structural information of SARS-CoV-2 and molecular steps that help this virus target AECs are appreciably studied. Furthermore, the heterogeneous and complex nature of COVID-19 is extensively revealed at molecular, genetic, and epigenetic and microenvironment levels. In spite of these developments in COVID-19 pathogenesis, the reasons behind the targeted infection by SARS-CoV-2 to AECs are poorly understood. In this mini-review, we highlight the roles of pH and temperature of airway surface liquid [ASL] as a key determining factor that may contribute towards enhanced targeted infection by SARS-CoV-2 leading to COVID- 19.

Gastrointestinal (GI) cancers presented an alarmingly high number of new cancer cases worldwide and are highly characterised by poor prognosis. The poor overall survival is mainly due to late detection and emerging challenges in treatment, particularly chemoresistance. Thus, the identification of novel molecular targets in GI cancer is highly regarded as the main focus. Recently, long non-coding RNAs (lncRNAs) have been discovered as potential novel molecular targets for combating cancer, as they are highly associated with carcinogenesis and have a great impact on cancer progression. Amongst lncRNAs, HOTTIP has demonstrated a prominent oncogenic regulation in cancer progression, particularly in GI cancers, including oesophageal cancer, gastric cancer, hepatocellular carcinoma, pancreatic cancer, and colorectal cancer. This review aimed to present a focused update on the regulatory roles of HOTTIP in GI cancer progression and chemoresistance, as well as deciphering the associated molecular mechanisms underlying their impact on cancer phenotypes and chemoresistance and the key molecules involved. It has been reported that it regulates the expression of various genes and proteins in GI cancers that impact cellular functions, including proliferation, adhesion, migration and invasion, apoptosis, chemosensitivity, and tumour differentiation. Furthermore, HOTTIP was also discovered to have a higher diagnostic value as compared to existing diagnostic biomarkers. Overall, HOTTIP has presented itself as a novel therapeutic target and potential diagnostic biomarker in the development of GI cancer treatment.

Exosomal vesicles enclose and carry a broad range of biological molecules, such as nucleic acids, lipids, and proteins, and transfer them between cells. In cancer, cells being mentioned could be neighbors in the same tumor microenvironment communicating with each other, or they could be localized at distant sites of the body, enabling suitable conditions for metastasis. Either way, it is a concrete fact that cells under physiological or pathological conditions make crosstalk via exosomal secretion. This review looks at the relation between exosomal cargo and mechanisms of cancer through recent research.

Brain tissue is known to have elevated citrate levels, necessary to regulate ion chelation, neuron excitability, and are also necessary for the supply of necessary energy substrates to neurons. Importantly, citrate also acts as a central substrate in cancer metabolism. Recent studies have shown that extracellular citrate levels in the brain undergo significant changes during tumor development and may play a dual role in tumor progression, as well as cancer cell aggressiveness. In the present article, we review available literature describing changes of citrate levels in brain tissue, blood, and cerebrospinal fluid, as well as intracellular alterations during tumor development before and after metastatic progression. Based on the available literature and our recent findings, we hypothesize that changes in extracellular citrate levels may be related to the increased consumption of this metabolite by cancer cells. Interestingly, cancerassociated cells, including reactive astrocytes, might be a source of citrate. Extracellular citrate uptake mechanisms, as well as potential citrate synthesis and release by surrounding stroma, could provide novel targets for anti-cancer treatments of primary brain tumors and brain metastases.

Hepatitis B virus [HBV], the best-described hepadnavirus, is distributed all around the world and may lead to chronic and acute liver disease, cirrhosis, and hepatocellular carcinoma. Despite the advancement in treatment against HBV, an errorprone reverse transcriptase, which is required for HBV replication as well as host immune pressure, leads to constant evolution and emergence of genotypes, subgenotypes and mutant viruses; so, HBV will remain as a major healthcare problem around the world. This review article mainly focuses on the HBV mutations which correlated to occult HBV infection, immune escape, vaccine failure and eventually liver cirrhosis and HCC. The current study indicated that preS/S region mutations are related to vaccine failure, immune escape, occult HBV infection and the occurrence of HCC. Whereas P region Mutations may lead to drug resistance to NA antivirals. PreC/C region mutations are associated with HBeAg negativity, immune escape, and persistent hepatitis. Moreover, X region Mutations play an important role in HCC development.

Today, Platelets and platelet-derived nanoparticles and microparticles have found many applications in nanomedical technology. The results of our review study show that no article has been published in this field to review the current status of applications of these platelet derivatives so far. Therefore, in the present study, our goal is to compare the applications of platelet derivatives and review their latest status between 2010 and 2020 to present the latest findings to researchers. A very interesting point about the role of platelet derivatives is the presence of molecules on their surface, which makes them capable of hiding from the immune system, reaching different target cells, and specifically attaching to different cell types. According to the results of this study, most of their applications include drug delivery, diagnosis of various diseases, and tissue engineering. However, their application in drug delivery is limited due to heterogeneity, large size, and the possibility of interference with cellular pathways in microparticles derived from other cells. On the other hand, platelet nanoparticles are more controllable and have been widely used for drug delivery in the treatment of cancer, atherosclerosis, thrombosis, infectious diseases, repair of damaged tissue, and photothermal therapy. The results of this study show that platelet nanoparticles are more controllable than platelet microparticles and have a higher potential for use in medicine.

Exosomes, nanosized extracellular vesicles with a size of 30–150nm, contain many biological materials, such as messenger RNA (mRNA), microRNA (miRNA), proteins, and transcription factors. It has been identified in all biological fluids and recognized as an important part of intercellular communication. While the role of exosomes in cancer has been studied in-depth, our understanding of their relevance for ocular tissues has just begun to evolve. Intraocular fluids, including aqueous humor and vitreous humor, play a role in nourishing eye tissues and in expelling metabolites. In the pathological state, intraocular exosomes can mediate pathological processes such as ECM remodeling, retinal inflammation, and blood-retinal barrier dysfunction. Herein, we reviewed the latest advances of intraocular exosomes in the research of several eye diseases, including glaucoma, age-related macular degeneration, myopia, and ocular tumors, and discuss how intraocular exosomes contribute to the pathogenesis and progression of multiple eye diseases.

Background: The dynamic changes that bone undergoes during the ensemble of remodeling are administered by vital factors like Runx2 (a bone transcription factor) and matrix metalloproteinases (MMPs). Aims: Parathyroid hormone (PTH), an FDA approved drug for bone-related ailments, was seen to stimulate MMP-13 expression via Runx2 to ultimately aid in the bone remodeling process. MicroRNAs (miRNAs) have been shown to play a major role in controlling bone metabolism, and the use of miRNAs has recently become promising therapeutic avenues for the treatment of many diseases, including bone disorders. Thus, in this study, we attempted to investigate and evaluate the expression of MMP-13 via a miRNA profile targeting Runx2 under PTH-regulation in rat osteoblastic cells. Methods: PTH stimulated the expression of MMP-13 mRNA significantly at 4 h in rat osteoblastic cells (UMR106-01). Runx2 was required for PTH-stimulation of MMP-13 expression, in silico scrutiny generated 14 unique miRNAs targeting Runx2, and among these miRNAs, miR-290 was significantly downregulated by PTH-treatment in UMR106- 01 cells and in rat primary osteoblasts. Results: Overexpression of miR-290 decreased the expression of Runx2, the binding of Runx2 at the MMP-13 promoter, and the expression of MMP-13 mRNA in PTH-treated UMR106-01 cells. A dual luciferase reporter assay identified the direct targeting of Runx2 mRNA by miR-290 in these cells. Conclusion: Our findings indicate that the PTH-responsive miR-290 regulated Runx2- mediated MMP-13 expression in rat osteoblastic cells, suggesting miR-290 as a molecular marker or target in bone and bone-related diseases.