A pathogenic C terminus-truncated polycystin-2 mutant enhances receptor-activated Ca2+ entry via association with TRPC3 and TRPC7.

Mutations in PKD2 gene result in autosomal dominant polycystic kidney disease (ADPKD). PKD2 encodes polycystin-2 (TRPP2), which is a homologue of transient receptor potential (TRP) cation channel proteins. Here we identify a novel PKD2 mutation that generates a C-terminal tail-truncated TRPP2 mutant 697fsX with a frameshift resulting in an aberrant 17-amino acid addition after glutamic acid residue 697 from a family showing mild ADPKD symptoms. When recombinantly expressed in HEK293 cells, wild-type (WT) TRPP2 localized at the endoplasmic reticulum (ER) membrane significantly enhanced Ca2+ release from the ER upon muscarinic acetylcholine receptor (mAChR) stimulation. In contrast, 697fsX, which showed a predominant plasma membrane localization characteristic of TRPP2 mutants with C terminus deletion, prominently increased mAChR-activated influx in cells expressing TRPC3 or TRPC7. Coimmunoprecipitation, pulldown assay, and cross-linking experiments revealed a physical association between 697fsX and TRPC3 or TRPC7. 697fsX but not WT TRPP2 elicited a depolarizing shift of reversal potentials and an enhancement of single-channel conductance indicative of altered ion-permeating pore properties of mAChR-activated currents. Importantly, in kidney epithelial LLC-PK1 cells the recombinant 679fsX construct was codistributed with native TRPC3 proteins at the apical membrane area, but the WT construct was distributed in the basolateral membrane and adjacent intracellular areas. Our results suggest that heteromeric cation channels comprised of the TRPP2 mutant and the TRPC3 or TRPC7 protein induce enhanced receptor-activated Ca2+ influx that may lead to dysregulated cell growth in ADPKD. © 2009 by The American Society for Biochemistry and Molecular Biology, Inc.Publisher\u27s version/PDF may be used after 12 months embarg

A maintenance hemodialysis patient complicated with hypogammaglobulinemia presenting typical COVID-19 pneumonia CT findings: a case report

Abstract Background With the widespread use of the vaccine and the predominance of the Omicron strain, the number of patients presenting with typical coronavirus-infection disease 2019 (COVID-19) pneumonia on computed tomography (CT) has decreased dramatically. This has also been true for hemodialysis patients. Case report A 72-year-old female maintenance hemodialysis patient with hypogammaglobulinemia was diagnosed with COVID-19 based on a nasopharyngeal swab severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) polymerase chain reaction (PCR) test. She had previously received five doses of COVID-19 BNT162b2 vaccine. Initially, the patient had only a slight fever, mild sore throat and sputum, and molnupiravir 1600 mg/day was administered for 5 days. No high fever was observed during that period. On day 11 after diagnosis, bloody sputum was observed, and by day 13 the cough had worsened and her CRP level had increased to 13.10 mg/dL. Chest CT performed on the same day showed multiple subpleural ground-glass-like shadows typical of COVID-19 pneumonia predominantly in the right lung. She was immediately admitted to the hospital, where her temperature rose to 38.4 °C. Intravenous remdesivir 100 mg/day was administered for 5 days. This resolved her fever and the bloody sputum disappeared. She was discharged from the hospital without sequelae on the 21st day after diagnosis. Conclusion We experienced a case of typical COVID-19 pneumonia in a patient on maintenance hemodialysis who had received five doses of COVID-19 BNT162b2 vaccine. There was a flare-up of symptoms after administration of molnupiravir, suggesting that a hypogammaglobulinemia complication was involved. This highlights the need for attention to its potential transition to severe disease when patients with hypogammaglobulinemia or other highly immunocompromised conditions are affected by COVID-19

Robust antibody response after the third mRNA coronavirus vaccination in Japanese hemodialysis patients

Abstract Background Hemodialysis patients have chronic kidney disease, are often elderly, and have many complications such as hypertension, type 2 diabetes, cardiac disease, and cerebrovascular disease. Therefore, hemodialysis patients infected with COVID-19 are prone to severe disease. Vaccination is the most promising means of preventing the onset and reducing the severity of COVID-19. However, many reports have found that anti-spike antibody titers after two doses of mRNA vaccine are lower in hemodialysis patients than in healthy controls. For this reason, a third vaccination is recommended for hemodialysis patients. In Japan, there are several reports of a third vaccination, especially for hemodialysis patients. In this study, we also examined the antibody response to COVID-19 vaccine in Japanese hemodialysis patients who received the third dose of the vaccine. Methods Study participants received a third vaccination (257 with BNT162b2 vaccine and 5 with mRNA-1273 vaccine) approximately 7–9 months after the second (BNT162b2 vaccine). Anti-SARS-CoV-2 spike IgG antibody titers were measured (Abbott SARS-CoV-2 IgG II Quan) in 185 hemodialysis patients and 109 healthcare workers approximately 2 weeks after the second vaccination and in 162 hemodialysis patients and 100 healthcare workers approximately 2 weeks after the third. Results Following the second vaccination, 97.6% of the hemodialysis group and 100% of the control group were positive for the anti-spike antibody. The median level of the anti-spike antibody was 2728.7 AU/mL (IQR, 1024.2–7688.2 AU/mL) in the hemodialysis group and 10,500 AU/ml (IQR, 9346.1–2,4500 AU/mL) in the controls. Following the third vaccination, 99.4% of the hemodialysis group (only one person tested negative for the antibody) and 100% of the control group were positive for the anti-spike antibody. The median level of the anti-spike antibody was 20,000 AU/mL (IQR, 7729–37,000 AU/mL) in the hemodialysis group and 21,500 AU/ml (IQR, 14,000–32,250 AU/mL) in the control group. The factors involved in the low response to the BNT152b2 vaccine after the second vaccination included old age, low BMI, low Cr index, low nPCR, low GNRI, low lymphocyte count, steroid administration, and complications related to blood disorders. However, in hemodialysis patients, the response after the third vaccination was excellent, and all factors associated with the suppressed response to these vaccines were no longer significant. Conclusions The humoral response of hemodialysis patients to two doses of mRNA vaccine was weaker than that of healthy controls. However, a third vaccination eliminated that difference

Formation of lipid droplets induced by 2,3-dihydrogeranylgeranoic acid distinct from geranylgeranoic acid

Geranylgeranoic acid (GGA) and 2,3-dihydrogeranylgeranoic acid (2,3-diGGA) are geranylgeraniol-derived metabolites (Kodaira et al. (2002) J Biochem 132: 327-334). In the present study, we examined the effects of these acids on HL-60 cells. The cells were differentiated into neutrophils by GGA stimulation like retinoic acid stimulation. In the case of cells stimulated with 2,3-diGGA, neutrophils were not detected, but the formation of lipid droplets was induced. On the other hand, when the cells were cultured in the presence of 0.1% FBS instead of 10% FBS, apoptotic cells were induced not only by GGA stimulation but also with 2,3-diGGA. In the latter case, when the cells were cultured in the co-presence of a caspase-3 inhibitor (Ac-DMQD-CHO), the lipid droplets formation was observed in the cells. These results suggest that GGA and 2,3-diGGA are extremely different from each other with respect to their effects on HL-60 cells