Molecular markers predicting the progression and prognosis of human papillomavirus-induced cervical lesions to cervical cancer.

INTRODUCTION: Persistent Human Papillomavirus (HPV) infection is linked to 99% of cervical cancer (CC) cases. HPV types 16 and 18 alone result in 75% of CC cases and thus are considered to be high-risk types (HR-HPV). CC is the third most common cancer among women globally. Approximately, 7000 patients die from it yearly. It is worthy to note that not every patient with HPV precancerous lesions will progress to CC. OBJECTIVES: The objectives of this review is to explore the utilization of molecular and viral biomarkers as a tool for early detection and prediction of HPV-induced cervical lesions that might progress to CC. METHODS: The data bases PubMed, Google Scholar, EBSCO were searched using keywords CC screening, HPV, and recent molecular biomarkers. The search time frame was within the last 7 years. Studies on HPV-induced cancers other than CC were excluded; a total of 200 eligible articles were retrieved. RESULTS: In this review we explored the current literature about HPV virology, virulence genes and early diagnostic/prognostic molecular biomarkers in CC. The oncogenic property of HPV is attributed to viral expression of various early proteins (E5, E6, E7). The interaction between viral oncoproteins and the cellular genetic apparatus alters the expression of many genes at different phases of the disease. There was an association between cervical lesions induced by HR-HPV and the overexpression of markers of oxidative DNA damage and other proteins. The markers p16INK4a, programmed cell death-1 (PD-1)/programmed cell death ligand 1, mismatch repair enzymes (MMR), miRNA-377, claudin family (CLDN) are dysregulated and are associated with high risk lesions. Furthermore, advanced older cervical lesions were associated with high methylation levels and higher risk to progress to CC. CONCLUSION: Adding different the above markers to the CC screening program scheme might offer a triage for prioritizing patient management.

Enhanced endocytosis elevated virulence and severity of SARS-CoV-2 due to hyperglycemia in type 2 diabetic patients.

Diabetes mellitus is a metabolic disease that causes hyperglycemia. In COVID-19 patients the severity of the disease depends on myriad factors but diabetes mellitus is the most important comorbidity. The current review was conducted to investigate the virulence of SARS-CoV-2 and disease severity of COVID-19 in type 2 diabetes mellitus patients and relevant treatment. The literature published in PubMed, Scopus, Web of Science, and Google Scholar was reviewed up to September 2021. The keywords including SARS-CoV-2, type 2 diabetes mellitus in COVID-19, hyperglycemia in COVID-19, opportunistic infections in type 2 diabetes mellitus and COVID-19 were used in different combinations. Hyperglycemic individuals over-express ACE-2 receptors in the lungs thus increasing the SARS-CoV-2 susceptibility and replication. Although dipeptidyl peptidase-4 plays an important role in glucose homeostasis, additionally it also stimulates the production of proinflammatory cytokines such as IL-6 and TNF-α creating a cytokine storm. Cytokine storm might be responsible for respiratory insufficiency in severe COVID-19 patients. Type 2 diabetes mellitus is associated with immunosuppression and the patients are prone to get many opportunistic infections. Type 2 diabetes mellitus patients with severe COVID-19 have lymphopenia. Moreover, in type 2 diabetes mellitus patients the neutrophils exhibit decreased chemotaxis, hydrogen peroxide production, and phagocytosis. Reduction in lymphocyte count and defective neutrophil capacity renders them with COVID-19 susceptible to opportunistic bacterial and fungal infections increasing the mortality rate. The opportunistic bacterial infections in COVID-19 patients were due to Staphylococcus aureus, Streptococcus pneumonia, and coagulase-negative Staphylococci, E. coli, Pseudomonas aeruginosa, and Klebsiella sp. In COVID-19 patients with type 2 diabetes mellitus, mucormycosis was found to be the most common fungal infection with a higher predilection to males. Hyperglycemia in COVID-19 patients with type 2 diabetes mellitus enhances the SARS-CoV-2 replication with an adverse outcome. A strong correlation exists between the poor prognosis of COVID-19 and type 2 diabetes mellitus. Proper glycemic control in COVID-19 patients with diabetes mellitus might lessen the severity of the disease.

Global data analysis and risk factors associated with morbidity and mortality of COVID-19.

This review was focused on global data analysis and risk factors associated with morbidity and mortality of coronavirus disease 2019 from different countries, including Bangladesh, Brazil, China, Central Eastern Europe, Egypt, India, Iran, Pakistan, and South Asia, Africa, Turkey and UAE. Male showed higher confirmed and death cases compared to females in most of the countries. In addition, the case fatality ratio (CFR) for males was higher than for females. This gender variation in COVID-19 cases may be due to males' cultural activities, but similar variations in the number of COVID-19 affected males and females globally. Variations in the immune system can illustrate this divergent risk comparatively higher in males than females. The female immune system may have an edge to detect pathogens slightly earlier. In addition, women show comparatively higher innate and adaptive immune responses than men, which might be explained by the high density of immune-related genes in the X chromosome. Furthermore, SARS-CoV-2 viruses use angiotensin-converting enzyme 2 (ACE2) to enter the host cell, and men contain higher ACE2 than females. Therefore, males may be more vulnerable to COVID-19 than females. In addition, smoking habit also makes men susceptible to COVID-19. Considering the age-wise distribution, children and older adults were less infected than other age groups and the death rate. On the contrary, more death in the older group may be associated with less immune system function. In addition, most of these group have comorbidities like diabetes, high pressure, low lungs and kidney function, and other chronic diseases. Due to the substantial economic losses and the numerous infected people and deaths, research examining the features of the COVID-19 epidemic is essential to gain insight into mitigating its impact in the future and preparedness for any future epidemics.

Nodamura virus B2 amino terminal domain sensitivity to small interfering RNA.

Nodamura virus (NoV) B2, a suppressor of RNA interference, binds double stranded RNAs (dsRNAs) and small interfering RNAs (siRNAs) corresponding to Dicer substrates and products. Here, we report that the amino terminal domain of NoV B2 (NoV B2 79) specifically binds siRNAs but not dsRNAs. NoV B2 79 oligomerizes on binding to 27 nucleotide siRNA. Mutation of the residues phenylalanine49 and alanine60 to cysteine and methionine, respectively enhances the RNA binding affinity of NoV B2 79. Circular dichroism spectra demonstrated that the wild type and mutant NoV B2 79 have similar secondary structure conformations.

Effect of signal peptide on stability and folding of Escherichia coli thioredoxin.

The signal peptide plays a key role in targeting and membrane insertion of secretory and membrane proteins in both prokaryotes and eukaryotes. In E. coli, recombinant proteins can be targeted to the periplasmic space by fusing naturally occurring signal sequences to their N-terminus. The model protein thioredoxin was fused at its N-terminus with malE and pelB signal sequences. While WT and the pelB fusion are soluble when expressed, the malE fusion was targeted to inclusion bodies and was refolded in vitro to yield a monomeric product with identical secondary structure to WT thioredoxin. The purified recombinant proteins were studied with respect to their thermodynamic stability, aggregation propensity and activity, and compared with wild type thioredoxin, without a signal sequence. The presence of signal sequences leads to thermodynamic destabilization, reduces the activity and increases the aggregation propensity, with malE having much larger effects than pelB. These studies show that besides acting as address labels, signal sequences can modulate protein stability and aggregation in a sequence dependent manner.

Recognition of the let-7g miRNA precursor by human Lin28B.

Mammalian homologs of lin28: Lin28 and Lin28B block the post-transcriptional processing of the let-7 family of miRNAs. We report that in vitro the terminal stem-loop region of the let-7g miRNA precursor (pre-let-7g) required to bind Lin28B is restricted to 24 nucleotides (nt) including the 3' GGAG motif. Additionally, full length Lin28B is required for efficient binding to pre-let-7g and the stoichiometry of the complex is 1:1. Molecular dynamics (MD) simulations reveal the interactions of the pre-let-7g stem-loop and the GGAG motif in the stem region to the cold shock domain (CSD) and to the zinc knuckle domain (ZKD) of Lin28B, respectively.

Designed cyclic permutants of HIV-1 gp120: implications for envelope trimer structure and immunogen design.

Most HIV-1 broadly neutralizing antibodies are directed against the gp120 subunit of the env surface protein. Native env consists of a trimer of gp120-gp41 heterodimers, and in contrast to monomeric gp120, preferentially binds CD4 binding site (CD4bs)-directed neutralizing antibodies over non-neutralizing ones. Some cryo-electron tomography studies have suggested that the V1V2 loop regions of gp120 are located close to the trimer interface. We have therefore designed cyclically permuted variants of gp120 with and without the h-CMP and SUMO2a trimerization domains inserted into the V1V2 loop. h-CMP-V1cyc is one such variant in which residues 153 and 142 are the N- and C-terminal residues, respectively, of cyclically permuted gp120 and h-CMP is fused to the N-terminus. This molecule forms a trimer under native conditions and binds CD4 and the neutralizing CD4bs antibodies b12 with significantly higher affinity than wild-type gp120. It binds non-neutralizing CD4bs antibody F105 with lower affinity than gp120. A similar derivative, h-CMP-V1cyc1, bound the V1V2 loop-directed broadly neutralizing antibodies PG9 and PG16 with ∼20-fold higher affinity than wild-type JRCSF gp120. These cyclic permutants of gp120 are properly folded and are potential immunogens. The data also support env models in which the V1V2 loops are proximal to the trimer interface.

Protein stabilization by introduction of cross-strand disulfides.

Disulfides cross-link residues in a protein that are separated in primary sequence and stabilize the protein through entropic destabilization of the unfolded state. While the removal of naturally occurring disulfides leads to protein destabilization, introduction of engineered disulfides does not always lead to significant stabilization of a protein. We have analyzed naturally occurring disulfides that span adjacent antiparallel strands of beta sheets (cross-strand disulfides). Cross-strand disulfides have recently been implicated as redox-based conformational switches in proteins such as gp120 and CD4. The propensity of these disulfides to act as conformational switches was postulated on the basis of the hypothesis that this class of disulfide is conformationally strained. In the present analysis, there was no evidence to suggest that cross-strand disulfides are more strained compared to other disulfides as assessed by their torsional energy. It was also observed that these disulfides occur solely at non-hydrogen-bonded (NHB) registered pairs of adjacent antiparallel strands and not at hydrogen-bonded (HB) positions as suggested previously. One of the half-cystines involved in cross-strand disulfide formation often occurs at an edge strand. Experimental confirmation of the stabilizing effects of such disulfides was carried out in Escherichia coli thioredoxin. Four pairs of cross-strand cysteines were introduced, two at HB and two at NHB pairs. Disulfides were formed in all four cases. However, as predicted from our analysis, disulfides at NHB positions resulted in an increase in melting temperature of 7-10 degrees C, while at HB positions there was a corresponding decrease of -7 degrees C. The reduced state of all proteins had similar stability.