DOCK2 is involved in the host genetics and biology of severe COVID-19

「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target

Structural analysis of pituitary adenylate cyclase-activating polypeptides bound to phospholipid membranes by magic angle spinning solid-state NMR

AbstractPACAP (pituitary adenylate cyclase-activating polypeptide) is a member of the VIP/secretin/glucagon family, which includes the ligands of class II G-protein coupled receptors. Since the recognition of PACAP by the receptor may involve the binding of PACAP to membranes, its membrane-bound structure should be important. We have carried out structural analysis of uniformly 13C,15N labeled PACAP27 and its C-terminal truncated form PACAP(1–21)NH2 (PACAP21) bound to membranes with high resolution solid-state NMR. Phosphatidylcholine bilayers and phosphatidylcholine/phosphatidylglycerol bilayers were used for PACAP27 and PACAP21, respectively. Most backbone signals were assigned for PACAP27 and PACAP21. TALOS analysis revealed that both peptides take on extended conformations on the membranes. Dilution of PACAP21 did not change the conformation of the major part. Selective polarization transfer experiment confirmed that PACAP27 is interacting with the membranes. It was concluded that the interaction of PACAP with the membrane surface causes their extended conformation. PACAP27 is reported to take an α-helical conformation in dodecylphosphocholine micelles and membrane-binding peptides usually take similar conformations in micelles and in membranes. Therefore, the property of PACAP27 changing its conformation in response to its environment is unique. Its conformational flexibility may be associated with its wide variety of functions

Successful local treatment for repeated hepatic recurrences of cholangiolocellular carcinoma: a report on a long-term survivor

Abstract Background Cholangiolocellular carcinoma (CoCC) is a rare liver tumor arising from the canals of Hering found between the cholangioles and interlobular bile ducts. Although morphologically CoCC mimics intrahepatic cholangiocarcinoma (ICC), CoCC exhibits a unique intermediate biologic behavior between hepatocellular carcinoma (HCC) and ICC. Curative resection is required for prolonged survival in patients with CoCC. However, effective therapy for postoperative hepatic recurrence has not yet been standardized. Case presentation A 40-year-old man had an asymptomatic liver mass found during a regular medical examination. Contrast-enhanced computed tomography revealed a well-enhanced mass, 15 cm in diameter, in the right liver. He underwent right hemihepatectomy at a local hospital under the preoperative diagnosis of hepatocellular carcinoma. Pathologic examination confirmed a moderately differentiated tubular adenocarcinoma, leading to a diagnosis of ordinary ICC. Twelve months after surgery, he was referred to our hospital due to three hepatic recurrences in the left medial segment. He underwent partial hepatectomy for the recurrence, followed by adjuvant chemotherapy using gemcitabine alone. After the second hepatectomy, hepatic recurrences developed an additional seven times. The numbers and sizes of the recurrent tumors were very limited at each recurrence, satisfying the standard criteria for percutaneous radiofrequency ablation (RFA) for the treatment of HCC. All lesions were treated by percutaneous RFA, although this was an exceptional approach for ICC. He is now alive without evidence of disease 9.2 years after the first hepatectomy. Because his clinical outcome was satisfactory and not compatible with the typical negative outcomes of ordinary ICC, we re-reviewed the histological findings of his tumor. The tumor was composed of small gland-forming cells proliferating in an anastomosing pattern; the cell membrane was strongly immunoreactive for epithelial membrane antigen. These findings were in accordance with the typical features of CoCC, revising his final diagnosis from ICC to CoCC. Conclusions This case report demonstrates a satisfactory outcome using repeated local treatments, such as hepatectomy and RFA, for hepatic recurrences of CoCC, suggesting that a localized treatment approach can be considered to be a therapeutic option. We should be careful in making a definitive diagnosis of ICC and ruling out CoCC because the diagnosis potentially dictates the treatment strategy for recurrences

An NMR Biochemical Assay for Fragment-Based Drug Discovery: Evaluation of an Inhibitor Activity on Spermidine Synthase of Trypanosoma cruzi

Although NMR in fragment-based drug discovery is utilized almost exclusively to evaluate physical binding between molecules, it should be also a powerful tool for biochemical assay, evaluating inhibitory effect of compounds on enzymatic activity. Time-dependent spectral change in real-time monitoring or inhibitor concentration-dependent spectral change after constant-time reaction was processed by factor analysis, by which reaction rate or IC₅₀ value was obtained. Applications to spermidine synthase of Trypanosoma cruzi, which causes Chagas disease, are described