Comparative Analysis of Antibody Titers against the Spike Protein of SARS-CoV-2 Variants in Infected Patient Cohorts and Diverse Vaccination Regimes.

The presence of neutralizing antibodies against SARS-CoV-2 correlates with protection against infection and severe COVID-19 disease courses. Understanding the dynamics of antibody development against the SARS-CoV-2 virus is important for recommendations on vaccination strategies and on control of the COVID-19 pandemic. This study investigates the dynamics and extent of α-Spike-Ab development by different vaccines manufactured by Johnson & Johnson, AstraZeneca, Pfizer-BioNTech and Moderna. On day 1 after vaccination, we observed a temporal low-grade inflammatory response. α-Spike-Ab titers were reduced after six months of vaccination with mRNA vaccines and increased 14 days after booster vaccinations to a maximum that exceeded titers from mild and critical COVID-19 and Long-COVID patients. Within the group of critical COVID-19 patients, we observed a trend for lower α-Spike-Ab titers in the group of patients who survived COVID-19. This trend accompanied higher numbers of pro-B cells, fewer mature B cells and a higher frequency of T follicular helper cells. Finally, we present data demonstrating that past infection with mild COVID-19 does not lead to long-term increased Ab titers and that even the group of previously infected SARS-CoV-2 patients benefit from a vaccination six months after the infection.

Early IFN-α signatures and persistent dysfunction are distinguishing features of NK cells in severe COVID-19.

Longitudinal analyses of the innate immune system, including the earliest time points, are essential to understand the immunopathogenesis and clinical course of coronavirus disease (COVID-19). Here, we performed a detailed characterization of natural killer (NK) cells in 205 patients (403 samples; days 2 to 41 after symptom onset) from four independent cohorts using single-cell transcriptomics and proteomics together with functional studies. We found elevated interferon (IFN)-α plasma levels in early severe COVD-19 alongside increased NK cell expression of IFN-stimulated genes (ISGs) and genes involved in IFN-α signaling, while upregulation of tumor necrosis factor (TNF)-induced genes was observed in moderate diseases. NK cells exert anti-SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) activity but are functionally impaired in severe COVID-19. Further, NK cell dysfunction may be relevant for the development of fibrotic lung disease in severe COVID-19, as NK cells exhibited impaired anti-fibrotic activity. Our study indicates preferential IFN-α and TNF responses in severe and moderate COVID-19, respectively, and associates a prolonged IFN-α-induced NK cell response with poorer disease outcome.

Multiparametric High Content Analysis for assessment of neurotoxicity in differentiated neuronal cell lines and human embryonic stem cell-derived neurons.

The potential for adverse neurotoxic reactions in response to therapeutics and environmental hazards continues to prompt development of novel cell-based assays to determine neurotoxic risk. A challenge remains to characterize and understand differences between assays and between neuronal cellular models in their responses to neurotoxicants if scientists are to determine the optimal model, or combination of models, for neurotoxicity screening. Most studies to date have focused on developmental neurotoxicity applications. This study reports the development of a robust multiparameter High Content Analysis (HCA) assay for neurotoxicity screening in three differentiated neuronal cell models - SH-SY5Y, PC12 and human embryonic stem cell-derived hN2™ cells. Using a multiplexed detection reagent panel (Hoechst nuclear stain; antibodies against ßIII-Tubulin and phosphorylated neurofilament subunit H, and Mitotracker(®) Red CMXRos), a multiparametric HCA assay was developed and used to characterize a test set of 36 chemicals. HCA data generated were compared to data generated using MTT and LDH assays under the same assay conditions. Data showed that multiparametric High Content Analysis of differentiated neuronal cells is feasible, and represents a highly effective method for obtaining large quantities of robust data on the neurotoxic effects of compounds compared with cytotoxicity assays like MTT and LDH. Significant differences were observed between the responses to compounds across the three cellular models tested, illustrating the heterogeneity in responses to neurotoxicants across different cell types. This study provides data strongly supporting the use of cellular imaging as a tool for neurotoxicity assessment in differentiated neuronal cells, and provides novel insights into the neurotoxic effects of a test set of compounds upon differentiated neuronal cell lines and human embryonic stem cell-derived neurons.

Nonproteasomal targets of the proteasome inhibitors bortezomib and carfilzomib: a link to clinical adverse events.

PURPOSE: Bortezomib (Velcade), a dipeptide boronate 20S proteasome inhibitor and an approved treatment option for multiple myeloma, is associated with a treatment-emergent, painful peripheral neuropathy (PN) in more than 30% of patients. Carfilzomib, a tetrapeptide epoxyketone proteasome inhibitor, currently in clinical investigation in myeloma, is associated with low rates of PN. We sought to determine whether PN represents a target-mediated adverse drug reaction (ADR). EXPERIMENTAL DESIGN: Neurodegenerative effects of proteasome inhibitors were assessed in an in vitro model utilizing a differentiated neuronal cell line. Secondary targets of both inhibitors were identified by a multifaceted approach involving candidate screening, profiling with an activity-based probe, and database mining. Secondary target activity was measured in rats and patients receiving both inhibitors. RESULTS: Despite equivalent levels of proteasome inhibition, only bortezomib reduced neurite length, suggesting a nonproteasomal mechanism. In cell lysates, bortezomib, but not carfilzomib, significantly inhibited the serine proteases cathepsin G (CatG), cathepsin A, chymase, dipeptidyl peptidase II, and HtrA2/Omi at potencies near or equivalent to that for the proteasome. Inhibition of CatG was detected in splenocytes of rats receiving bortezomib and in peripheral blood mononuclear cells derived from bortezomib-treated patients. Levels of HtrA2/Omi, which is known to be involved in neuronal survival, were upregulated in neuronal cells exposed to both proteasome inhibitors but was inhibited only by bortezomib exposure. CONCLUSION: These data show that bortezomib-induced neurodegeneration in vitro occurs via a proteasome-independent mechanism and that bortezomib inhibits several nonproteasomal targets in vitro and in vivo, which may play a role in its clinical ADR profile.

Condom perforation during transrectal ultrasound guided (TRUS) prostate biopsies: a potential infection risk.

INTRODUCTION: Transrectal ultrasound (TRUS) guided prostate biopsies are amongst the most common outpatient diagnostic procedures performed in urology practice. Of concern appear to be recent reports of infectious complications following this procedure in which contamination of the biopsy equipment was the likely source. This study looks at the rate of condom perforation during prostate biopsy and we look to highlight the potential problems, which may arise as a result of inadequate cleansing of the equipment between cases during a busy prostate biopsy clinic MATERIAL AND METHODS: All patients attending for prostate biopsies over a three-month period in our institution were included in the study. All condoms (latex) used were made by the same manufacturer and were checked prior to the procedure and found to have no leaks. The biopsy gun was inserted through an externally placed needle guide, as is standard practice in many departments in the UK. After the end of each procedure the condom was removed from the rectal probe and filled once again with water to assess for perforations. Two experienced surgeons carried out all the procedures. RESULTS: 10 out of 107 patients were found to have at least one perforation in the condom. In some of the condoms there were multiple perforations. DISCUSSION: We have demonstrated a significant condom perforation rate (9%) amongst patients undergoing prostate biopsies. This raises the serious issue of hygiene and cross infection, particularly with blood borne communicable diseases such as hepatitis and HIV unless strict disinfection and sterilization protocols are followed between patients. Perforation of the condoms used during TRUS guided prostate biopsy and hence faecal and blood contamination of the biopsy equipment could potentially have far-reaching implications for urologists and the infection control community. Although the risk of cross infection is probably small this serious issue needs addressing.

Actions of glucagon-like peptide-1 on KATP channel-dependent and -independent effects of glucose, sulphonylureas and nateglinide.

This study examined the effects of glucagon-like peptide-1 (GLP-1) on insulin secretion alone and in combination with sulphonylureas or nateglinide, with particular attention to K(ATP) channel-independent insulin secretion. In depolarised cells, GLP-1 significantly augmented glucose-induced K(ATP) channel-independent insulin secretion in a glucose concentration-dependent manner. GLP-1 similarly augmented the K(ATP) channel-independent insulin-releasing effects of tolbutamide, glibenclamide or nateglinide. Downregulation of protein kinase A (PKA)- or protein kinase C (PKC)-signalling pathways in culture revealed that the K(ATP) channel-independent effects of sulphonylureas or nateglinide were critically dependent upon intact PKA and PKC signalling. In contrast, GLP-1 exhibited a reduced but still significant insulin-releasing effect following PKA and PKC downregulation, indicating that GLP-1 can modulate K(ATP) channel-independent insulin secretion by protein kinase-dependent and -independent mechanisms. The synergistic insulin-releasing effects of combinatorial GLP-1 and sulphonylurea/nateglinide were lost following PKA- or PKC-desensitisation, despite GLP-1 retaining an insulin-releasing effect, demonstrating that GLP-1 can induce insulin release under conditions where sulphonylureas and nateglinide are no longer effective. Our results provide new insights into the mechanisms of action of GLP-1, and further highlight the promise of GLP-1 or similarly acting analogues alone or in combination with sulphonylureas or meglitinide drugs in type 2 diabetes therapy.

Telomere-independent cellular senescence in human fetal cardiomyocytes.

Fetal cardiomyocytes have been proposed as a potential source of cell-based therapy for heart failure. This study examined cellular senescence in cultured human fetal ventricular cardiomyocytes (HFCs). HFCs were isolated and identified by immunocytochemistry and RT-PCR. Cells were found to senesce after 20-25 population doublings, as determined by growth arrest, morphological changes and senescence-associated beta-galactosidase activity. Using the telomeric repeat amplification protocol assay, telomerase activity was undetectable in primary HFCs. Cells were transduced to express the human reverse transcriptase subunit (hTERT) of telomerase. This resulted in greatly increased telomerase activity, but no significant lifespan extension. Analysis of telomere length in primary HFCs revealed that the senescent phenotype was not accompanied by telomere shortening. Telomeres in hTERT-positive cells were elongated in comparison with primary cells, and elongation was retained in senescent cells. Levels of the tumor suppressor protein p16INK4A increased in all senescent cells whether telomerase-positive or -negative. Senescence was accompanied by a decline in transcript levels of the polycomb gene Bmi-1, Ets1 and Ets2 transcription factors, and Id1, Id2 and Id3 helix-loop-helix proteins, suggesting roles for these genes in maintenance of cardiomyocyte proliferative capacity. In addition to offering novel insights into the behavior of human fetal cardiomyocytes in culture, these findings have implications for the development of a cell-based therapy for cardiac injury using primary fetal heart tissue.

Alterations of insulin secretion following long-term manipulation of ATP-sensitive potassium channels by diazoxide and nateglinide.

Previous studies have shown that prolonged exposure to drugs, which act via blocking KATP channels, can desensitize the insulinotropic effects of drugs and nutrients acting via KATP channels. In this study, effects of prolonged exposure to diazoxide, a KATP channel opener, on beta cell function were examined using clonal BRIN-BD11 cells. The findings were compared to the long-term effects of KATP channel blockers nateglinide and tolbutamide. Following 18 h exposure to 200 microM diazoxide, the amounts of insulin secreted in response to glucose, amino acids and insulinotropic drugs were increased. Secretory responsiveness to a variety of agents acting via KATP channels was retained following prolonged diazoxide exposure. In contrast, 18 h exposure to 100 microM nateglinide significantly attenuated the insulin secretory responses to tolbutamide, nateglinide and BTS 67 582. Glucose- and L-alanine-stimulated insulin release were unaffected by prolonged nateglinide exposure, however responsiveness to L-leucine and L-arginine was diminished. Prolonged exposure to nateglinide had no effect on forskolin- and PMA-stimulated insulin release, and the overall pattern of desensitization was similar to that induced by 100 microM tolbutamide. We conclude that in contrast to chronic long-term KATP channel blockade, long-term diazoxide treatment is not harmful to KATP channel mediated insulin secretion and may have beneficial protective effects on beta cell function.