Jung Heon Kim

Long-term control of diabetes in immunosuppressed nonhuman primates (NHP) by the transplantation of adult porcine islets.

Pig islets are an alternative source for islet transplantation to treat type 1 diabetes (T1D), but reproducible curative potential in the pig‐to‐nonhuman primate (NHP) model has not been demonstrated. Here, we report that pig islet grafts survived and maintained normoglycemia for >6 months in four of five consecutive immunosuppressed NHPs. Pig islets were isolated from designated pathogen‐free (DPF) miniature pigs and infused intraportally into streptozotocin‐induced diabetic rhesus monkeys under pretreatment with cobra venom factor (CVF), anti‐thymocyte globulin (ATG) induction and maintenance with anti‐CD154 monoclonal antibody and low‐dose sirolimus. Ex vivo expanded autologous regulatory T cells were adoptively transferred in three recipients. Blood glucose levels were promptly normalized in all five monkeys and normoglycemia (90–110 mg/dL) was maintained for >6 months in four cases, the longest currently up to 603 days. Intravenous glucose tolerance tests during the follow‐up period showed excellent glucose disposal capacity and porcine C‐peptide responses. Adoptive transfer of autologous regulatory T cells was likely to be associated with more stable and durable normoglycemia. Importantly, the recipients showed no serious adverse effects. Taken together, our results confirm the clinical feasibility of pig islet transplantation to treat T1D patients without the need for excessive immunosuppressive therapy.

Human Cytomegalovirus (HCMV) IE1 Plays Role in Resistance to Apoptosis with Etoposide in Cancer Cell Line by Cdk2 Accumulation

Human cytomegalovirus (HCMV) has many strategies to survive the attack of the host. HCMV infection of host cells induces cellular activation and disturbance of the cell cycle. It is possible that HCMV modulates the behavior of certain cancer cells that are susceptible to HCMV infection. This study was performed to identify the possible mechanism of resistance to apoptotic stimuli in some cancer cell lines by HCMV infection. HCMV‐infected cancer cells showed resistance to apoptosis induced by the topoisomerase II inhibitor etoposide. UMG1–2, which constitutively expresses HCMV immediate‐early protein‐1 (IE1), had resistance to apoptosis induced by etoposide as compared with the parental cell line U373MG. Measurement of caspases activity with fluorogenic substrates in etoposide‐treated U373MG and UMG1–2 cells and the direct activation of caspase‐3 with peptides containing arginine‐glycine‐aspartate in U373MG and UMG1–2 cells revealed that the inhibition level of apoptosis by HCMV IE1 would be upstream of caspase‐3 in the caspase cascade pathway. Cellular expression of Cdk2 was increased in UMG1–2 after etoposide treatment while the expression of E2F‐1 in UMG1–2 was decreased as compared with that in U373MG. The Cdk2 inhibitor, roscovitine, decreased the resistance to apoptosis on etoposide‐treated UMG1–2. These results suggest that aberrant HCMV infection confers resistance to anticancer drugs on some cancer cells and protects cells from apoptosis, possibly due to the deregulation of cyclin‐dependent kinase by HCMV immediate‐early protein.

Inhibition of p53 transcriptional activity by human cytomegalovirus UL44

Human cytomegalovirus (HCMV) stimulates cellular synthesis of DNA and proteins and induces transition of the cell cycle from G1 to S and G2/M phase, in spite of increased amounts of p53 in the infected cells. The immediate early protein IE2–86 kDa (IE86) tethers a transcriptional repression domain to p53; however, its repression of p53 function is not enough to abrogate the G1 checkpoint function of p53. Other HCMV proteins that suppress the activity of p53 were investigated in this study. Of the HCMV proteins that bind to p53 when assessed by immunoprecipitation and immunoblot analysis, HCMV UL44 was chosen as a candidate protein. It was found that reporter gene containing p53 consensus sequence was activated by transfection with wild type p53, but when plasmids of p53 with IE86 or UL44 were co‐transfected, p53 transcriptional activity was decreased to 3–7% of the p53 control in a dose‐dependent manner. When the deletion mutant of UL44 was co‐transected with p53, the carboxyl one‐third portion of UL44 had little effect on inhibition of p53 transcriptional activity. The amount of mRNA p21 was measured in H1299 by real time PCR after transfection of the combination of p53 and UL44 vectors and it was found that p21 transcription by p53 was inhibited dose‐dependently by UL44. Increased G0/G1 and decreased S phases in p53 wild type‐transfected H1299 cells were recovered to the level of p53 mutant type‐transfected ones by the additional transfection of UL44 in a dose‐dependent manner. In conclusion, the transcriptional activity of p53 is suppressed by UL44 as well as by IE86.

Human Cytomegalovirus (HCMV) Infection in Osteosarcoma Cell Line Suppresses GM‐CSF Production by Induction of TGF‐β

This study was performed to elucidate the possible mechanism of the disturbance of hemopoiesis by HCMV infection. Saos‐2 cells constitutively express mRNA of GM‐CSF, and its expression was profoundly decreased by HCMV infection, which required full replication of the virus and was mediated by soluble factors released from the HCMV‐infected Saos‐2 cells. TGF‐β1 production was statistically and significantly increased from one day after HCMV infection. Expression and production of GM‐CSF in Saos‐2 cells were restored when a culture supernatant of HCMV‐infected Saos‐2 cells was reacted with neutralizing anti‐TGF‐β antibody. Conclusively, HCMV inhibits GM‐CSF expression in Saos‐2 cells partly by the increased production of TGF‐β1.

Three-dimensional dialysate flow analysis in a hollow-fiber dialyzer by perfusion computed tomography.

Perfusion computed tomography (PCT) is a means to rapidly and easily evaluate cerebral perfusion in patients presenting with acute stroke symptoms, which provides insights into capillary-level hemodynamics. In this study, we used PCT to analyze the 3-dimensional dialysate flow in a low-flux hemodialyzer equipped with a standard fiber bundle. The dynamic CT studies were performed with 64-channel multi-detector row CT (MDCT) at a dialysate flow rate of 500 ml/min and a 1.0 ml/sec injection rate of contrast agent. Central volume principle was used to calculate hydrodynamic parameters by deconvolution of time-density curves (TDCs). Functional maps of dialysate flow (DF), dialysate volume (DV), and mean transit time (MTT) could quantitatively describe the dialysate flow maldistribution, variations in fiber packing, and perfusion pressure distribution in a hemodialyzer, respectively. PCT by means of analysis was able to overcome the limitations of conventional imaging techniques for analyzing dialysate flow distributions in hollow-fiber dialyzers. Not only local hydrodynamic phenomena at microscopic level but also macroscopic flow behavior of dialysate were visualized quantitatively. Therefore, we concluded that PCT is a quantitative analysis method to provide better insights into hydrodynamics of hollow-fiber dialyzers and is expected to contribute to optimization of artificial kidneys.

An immunoassay using biotinylated single-walled carbon nanotubes as Raman biomarkers

A new immunoassay with biotinylated single-walled carbon nanotubes as persistent, non-photobleaching Raman biomarkers demonstrated excellent sensitivity and specificity.

Induction of PERV antigen in porcine peripheral blood mononuclear cells by human herpesvirus 1

Xenotransplantation represents one of alternative candidates for allotransplantation due to the chronic shortage of suitable human tissues; however, many obstacles remain. Expression and release of endogenous retroviral antigens by porcine cells after transplantation may evoke adverse immune responses in human subjects. Here, we examined whether human herpesvirus 1 (HHV‐1) could induce the production of porcine endogenous retrovirus (PERV) antigens in porcine peripheral blood mononuclear cells (PBMCs).

Reactive oxygen species-induced parthanatos of immunocytes by human cytomegalovirus-associated substance: ROS-induced parthanatos by HCMV

Previous studies have examined various immune evasion strategies of human cytomegalovirus (HCMV) to gain understanding of its pathogenesis. Although the mechanism that underlies immunocyte destruction near HCMV‐infected lesions has yet to be established, it is here shown that substances produced by HCMV‐infected cells induce death in several types of immunocytes, but not in fibroblasts or astrocytomas. These substances contain HCMV proteins and were termed HCMV‐associated insoluble substance (HCMVAIS). The mechanism by which HCMVAIS induces cell death was characterized to improve understanding the death of immunocytes near HCMV‐infected lesions. HCMVAIS were found to trigger production of intracellular nicotinamide adenine dinucleotide phosphate oxidase‐derived reactive oxygen species (ROS), resulting in cell death, this effect being reversed following treatment with ROS inhibitors. Cell death was not induced in splenocytes from NOX‐2 knockout mice. It was hypothesized that DNA damage induced by oxidative stress initiates poly ADP‐ribose polymerase‐1 (PARP‐1)‐mediated cell death, or parthanatos. HCMVAIS‐induced cell death is accompanied by PARP‐1 activation in a caspase‐independent manner, nuclear translocation of apoptosis‐inducing factor (AIF), and DNA fragmentation, which are typical features of parthanatos. Treatment with an AIF inhibitor decreased the rate of HCMVAIS‐induced cell death, this being confirmed by hematoxylin and eosin staining; cell death in most HCMV‐positive foci in serial section samples of a large intestine with HCMV infection was TUNEL‐positive, cleaved caspase 3‐negative and CD45‐positive. Taken together, these data suggest that HCMV inhibits local immune responses via direct killing of immunocytes near HCMV‐infected cells through ROS‐induced parthanatos by HCMVAIS.

An Urgent Need for Global Preparedness against the Reemergence of “Forgotten” Infectious Diseases in Korea

https://jkms.org Can you imagine deaths from liver failure after a hepatitis A viral (HAV) infection? Subacute sclerosing panencephalitis long after contracting measles? Infertility or subfertility from mumps? Varicella even after vaccinated for it, increasing zoster in all ages? These ailments are rare but well-known complications of each corresponding infectious disease, but they were hardly observed since the last decade because of the effective disease control with upgraded hygiene, well-programmed vaccination and antibiotics usage. (Fig. 1)

Changes of Epidemiological Characteristics of Japanese Encephalitis Viral Infection and Birds as a Potential Viral Transmitter in Korea

Japanese encephalitis (JE) cases have been increasingly reported recently especially in Seoul and its vicinity. Pigs are known as amplifying host of JE virus (JEV), but do not play an important role in these recent events because pig-breeding is not common in Seoul. The distribution and the density of migratory birds are correlated with JE cases in cities and they might be highly potential hosts contributing to transmit JEV in metropolitan areas. JE genotype and sero-prevalence in birds should be determined for the verification of the transmission route of JEV in the recent sporadic occurrence of JE cases in Seoul.