CAR T-cell therapy: Blessing of 21st century

More than twenty years of research on cellular immunotherapy has recently resulted in the development of genetically-modified T cell products that express synthetic chimeric antigen receptor (CAR) with specificity toward the cell-surface tumor antigens. Recent studies have demonstrated promising response rates after infusion of these cells in patients with B-cell precursor and mature B-cell neoplasms, including acute lymphoblastic leukemia, diffuse large B-cell lymphoma, and plasma cell myeloma. Given the satisfactory evidence of their outstanding therapeutic benefit, CD19-targeted CAR T cells have become the first genetic engineering element approved by the United States Food and Drug Administration to treat patients for whom other promising options are unavailable. While clinicians are widely using CAR T-cell therapies, the two most common toxicities are cytokine-release syndrome and CAR T cell-related neurotoxicity/encephalopathy syndrome. Moreover, some studies have explained that the relapse after receiving CAR T-cell therapy is caused by acquired resistance due to genetic mutation or splicing variants, leading to the loss or diminished surface expression of the target molecule in neoplastic cells. To overcome these caveats and achieve therapeutic success, restless efforts are ongoing toward the development of next-generation CAR T cells with more sophisticated design.This study was supported in part by Grants-in-Aid from the Japan Agency for Medical Research and Development (AMED) (19pc0101041s0101, 20ek0510027h0002, 21ek0510032h0002 to TI) and the Program of the network-type Joint Usage/Research Center for Radiation Disaster Medical Science of Hiroshima University, Nagasaki University, and Fukushima Medical University (to TI)

Concerted action of activation-induced cytidine deaminase and uracil-DNA glycosylase reduces covalently closed circular DNA of duck hepatitis B virus

13301乙第2050号博士（医学）金沢大学博士論文本文Full 以下に掲載：FEBS Letter 587(18) pp.3148-3152 2013. Elsevier B.V.. 共著者：Sajeda Chowdhury, Kouichi Kitamura, Miyuki Shimadu, Miki Koura, Masamichi Muramats

Concerted action of activation-induced cytidine deaminase and uracil-DNA glycosylase reduces covalently closed circular DNA of duck hepatitis B virus

Covalently closed circular DNA (cccDNA) forms a template for the replication of hepatitis B virus (HBV) and duck HBV (DHBV). Recent studies suggest that activation-induced cytidine deaminase (AID) functions in innate immunity, although its molecular mechanism of action remains unclear, particularly regarding HBV restriction. Here we demonstrated that overexpression of chicken AID caused hypermutation and reduction of DHBV cccDNA levels. Inhibition of uracil-DNA glycosylase (UNG) by UNG inhibitor protein (UGI) abolished AID-induced cccDNA reduction, suggesting that the AID/UNG pathway triggers the degradation of cccDNA via cytosine deamination and uracil excision. © 2013 Federation of European Biochemical Societies

Uracil DNA Glycosylase Counteracts APOBEC3G-Induced Hypermutation of Hepatitis B Viral Genomes: Excision Repair of Covalently Closed Circular DNA

The covalently closed circular DNA (cccDNA) of the hepatitis B virus (HBV) plays an essential role in chronic hepatitis. The cellular repair system is proposed to convert cytoplasmic nucleocapsid (NC) DNA (partially double-stranded DNA) into cccDNA in the nucleus. Recently, antiviral cytidine deaminases, AID/APOBEC proteins, were shown to generate uracil residues in the NC-DNA through deamination, resulting in cytidine-to-uracil (C-to-U) hypermutation of the viral genome. We investigated whether uracil residues in hepadnavirus DNA were excised by uracil-DNA glycosylase (UNG), a host factor for base excision repair (BER). When UNG activity was inhibited by the expression of the UNG inhibitory protein (UGI), hypermutation of NC-DNA induced by either APOBEC3G or interferon treatment was enhanced in a human hepatocyte cell line. To assess the effect of UNG on the cccDNA viral intermediate, we used the duck HBV (DHBV) replication model. Sequence analyses of DHBV DNAs showed that cccDNA accumulated G-to-A or C-to-T mutations in APOBEC3G-expressing cells, and this was extensively enhanced by UNG inhibition. The cccDNA hypermutation generated many premature stop codons in the P gene. UNG inhibition also enhanced the APOBEC3G-mediated suppression of viral replication, including reduction of NC-DNA, pre-C mRNA, and secreted viral particle-associated DNA in prolonged culture. Enhancement of APOBEC3G-mediated suppression by UNG inhibition was not observed when the catalytic site of APOBEC3G was mutated. Transfection experiments of recloned cccDNAs revealed that the combination of UNG inhibition and APOBEC3G expression reduced the replication ability of cccDNA. Taken together, these data indicate that UNG excises uracil residues from the viral genome during or after cccDNA formation in the nucleus and imply that BER pathway activities decrease the antiviral effect of APOBEC3-mediated hypermutation. © 2013 Kitamura et al

RNA editing of hepatitis B virus transcripts by activation-induced cytidine deaminase.

Activation-induced cytidine deaminase (AID) is essential for the somatic hypermutation (SHM) and class-switch recombination (CSR) of Ig genes. The mechanism by which AID triggers SHM and CSR has been explained by two distinct models. In the DNA deamination model, AID converts cytidine bases in DNA into uridine. The uridine is recognized by the DNA repair system, which produces DNA strand breakages and point mutations. In the alternative model, RNA edited by AID is responsible for triggering CSR and SHM. However, RNA deamination by AID has not been demonstrated. Here we found that C-to-T and G-to-A mutations accumulated in hepatitis B virus (HBV) nucleocapsid DNA when AID was expressed in HBV-replicating hepatic cell lines. AID expression caused C-to-T mutations in the nucleocapsid DNA of RNase H-defective HBV, which does not produce plus-strand viral DNA. Furthermore, the RT-PCR products of nucleocapsid viral RNA from AID-expressing cells exhibited significant C-to-T mutations, whereas viral RNAs outside the nucleocapsid did not accumulate C-to-U mutations. Moreover, AID was packaged within the nucleocapsid by forming a ribonucleoprotein complex with HBV RNA and the HBV polymerase protein. The encapsidation of the AID protein with viral RNA and DNA provides an efficient environment for evaluating AID's RNA and DNA deamination activities. A bona fide RNA-editing enzyme, apolipoprotein B mRNA editing catalytic polypeptide 1, induced a similar level of C-to-U mutations in nucleocapsid RNA as AID. Taken together, the results indicate that AID can deaminate the nucleocapsid RNA of HBV

RNA editing of hepatitis B virus transcripts by activation-induced cytidine deaminase

Activation-induced cytidine deaminase (AID) is essential for the somatic hypermutation (SHM) and class-switch recombination (CSR) of Ig genes. The mechanismby which AID triggers SHMand CSR has been explained by two distinct models. In the DNA deamination model, AID converts cytidine bases in DNA into uridine. The uridine is recognized by the DNA repair system, which produces DNA strand breakages and point mutations. In the alternative model, RNA edited by AID is responsible for triggering CSR and SHM. However, RNA deamination by AID has not been demonstrated. Here we found that C-to-T and G-to-A mutations accumulated in hepatitis B virus (HBV) nucleocapsid DNA when AID was expressed in HBV replicating hepatic cell lines. AID expression caused C-to-T mutations in the nucleocapsid DNA of RNase H-defective HBV, which does not produce plus-strand viral DNA. Furthermore, the RT-PCR products of nucleocapsid viral RNA from AID-expressing cells exhibited significant C-to-T mutations, whereas viral RNAs outside the nucleocapsid did not accumulate C-to-U mutations. Moreover, AID was packaged within the nucleocapsid by forming a ribonucleoprotein complex with HBV RNA and the HBV polymerase protein. The encapsidation of the AID protein with viral RNA and DNA provides an efficient environment for evaluating AID\u27s RNA and DNA deamination activities. A bona fide RNA-editing enzyme, apolipoprotein B mRNA editing catalytic polypeptide 1, induced a similar level of C-to-U mutations in nucleocapsid RNA as AID. Taken together, the results indicate that AID can deaminate the nucleocapsid RNA of HBV

TGF-β Suppression of HBV RNA through AID-Dependent Recruitment of an RNA Exosome Complex

Transforming growth factor (TGF)-β inhibits hepatitis B virus (HBV) replication although the intracellular effectors involved are not determined. Here, we report that reduction of HBV transcripts by TGF-β is dependent on AID expression, which significantly decreases both HBV transcripts and viral DNA, resulting in inhibition of viral replication. Immunoprecipitation reveals that AID physically associates with viral P protein that binds to specific virus RNA sequence called epsilon. AID also binds to an RNA degradation complex (RNA exosome proteins), indicating that AID, RNA exosome, and P protein form an RNP complex. Suppression of HBV transcripts by TGF-β was abrogated by depletion of either AID or RNA exosome components, suggesting that AID and the RNA exosome involve in TGF-β mediated suppression of HBV RNA. Moreover, AID-mediated HBV reduction does not occur when P protein is disrupted or when viral transcription is inhibited. These results suggest that induced expression of AID by TGF-β causes recruitment of the RNA exosome to viral RNP complex and the RNA exosome degrades HBV RNA in a transcription-coupled manner. © 2015 Liang et al

Alarming prevalence of Candida auris among critically ill patients in intensive care units in Dhaka City, Bangladesh

Background: Candida auris is a multidrug-resistant yeast capable of invasive infection with high mortality and healthcare-associated outbreaks globally. Due to limited labratory capacity, the burden of C. auris is unknown in Bangladesh. We estimated the extent of C. auris colonization and infection among patients in Dhaka city intensive care units. Methods: During August 2021–September 2022 at adult intensive care units (ICUs) and neonatal intensive care units (NICUs) of 1 government and 1 private tertiary-care hospital, we collected skin swabs from all patients and blood samples from sepsis patients on admission, mid-way through, and at the end of ICU or NICU stays. Skin swab and blood with growth in blood-culture bottle were inoculated in CHROMagar, and identification of isolates was confirmed by VITEK-2. Patient characteristics and healthcare history were collected. We performed descriptive analyses, stratifying by specimen and ICU type. Results: Of 740 patients enrolled, 59 (8%) were colonized with C. auris, of whom 2 (0.3%) later developed a bloodstream infection (BSI). Among patients colonized with C. auris, 27 (46%) were identified in the ICU and 32 (54%) were identified from the NICU. The median age was 55 years for C. auris–positive ICU patients and 4 days for those in the NICU. Also, 60% of all C. auris patients were male. Among 366 ICU patients, 15 (4%) were positive on admission and 12 (3%) became colonized during their ICU stay. Among 374 NICU patients, 19 (5%) were colonized on admission and 13 (4%) became colonized during their NICU stay. All units identified C. auris patients on admission and those who acquired it during their ICU or NICU stay, but some differences were observed among hospitals and ICUs (Figure). Among patients colonized on admission to the ICU, 11 (73%) were admitted from another ward, 3 (20%) were admitted from another hospital, and 1 (7%) were admitted from home. Of patients colonized on admission to the NICU, 4 (21%) were admitted from the obstetric ward, 9 (47%) were admitted from another hospital, and 6 (32%) were admitted from home. In addition, 18 patients with C. auris died (12 in the ICU and 6 in the NICU); both patients with C. auris BSIs died. Conclusions: In these Bangladesh hospitals, 8% of ICU or NICU patients were positive for C. auris, including on admission and acquired during their ICU or NICU stay. This high C. auris prevalence emphasizes the need to enhance case detection and strengthen infection prevention and control. Factors contributing to C. auris colonization should be investigated to inform and strengthen prevention and control strategies

Perceptions about Telemedicine among Populations with Chronic Diseases amid COVID-19: Data from a Cross-Sectional Survey

Chronic diseases, including non-communicable diseases (NCDs), have arisen as a severe threat to health and socio-economic growth. Telemedicine can provide both the highest level of patient satisfaction and the lowest risk of infection during a pandemic. The factors associated with its usage and patient adherence are not visible in Bangladesh's resource-constrained settings. Therefore, this study aimed to identify perceptions about telemedicine among populations with chronic diseases amid the COVID-19 pandemic. A closed-ended self-reported questionnaire was created, and the questionnaire was written, reviewed, and finalized by a public health investigator, a psychiatrist, and an epidemiologist. The data for this study were collected from individuals using simple random sampling and snowball sampling techniques. Ethics approval was granted, and written/verbal consent was taken before interviews. Most of the participants showed a positive attitude towards telemedicine. People aged 35-54 years old and a higher level of education were less frequently associated with willingness to receive telemedicine services for current chronic disease (WRTCCD) than their counterparts. People living in urban areas and lower-income participants were more strongly associated with WRTCCD. Additionally, people who did not lose their earnings due to the pandemic were less strongly associated with WRTCCD. However, the main strength of this research is that it is a broad exploration of patient interest in several general forms of telehealth. In Bangladesh, there are many opportunities for telemedicine to be integrated into the existing healthcare system, if appropriate training and education are provided for healthcare professionals