Establishment of the Dual Humanized TK-NOG Mouse Model for HIV-associated Liver Pathogenesis

Despite the increased life expectancy of patients infected with human immunodeficiency virus-1 (HIV-1), liver disease has emerged as a common cause of ...

Study on the Moisture Absorption and Desorption Rate of Bamboo Scrimber in a Hot-Humid Climatic Wind Tunnel

The absorption and desorption rate Uab is an important indicator to evaluate the hygric performance of hygroscopic building materials. However, standard ...

South China University of Technology

State Key Laboratory of Subtropical Building Science

University of Nebraska Medical Center

Ly49A receptors expressed on NK, NKT, and T cells play inhibitory roles in regulating the immune responses in vivo and in vitro. Whether or not injection of anti-Ly49A monoclonal antibody (mAb) YE1/48 can block allograft rejection has not been evaluated. Balb/c mouse recipients received intraperitoneal injections of YE1/48 mAb (0.5 mg) or control mAb or phosphate-buffered saline on days -1 and 10. On day 0, fully MHC-mismatched allogeneic C57BL/6 (B6) skin grafts were implanted. The skin graft survival and anti-donor humoral responses were observed. Whereas allogeneic B6 skin grafts survived 14 days in isotopy control antibody-treated or nontreated Balb/c mice, injection of YE1/48 mAb significantly prolonged B6 skin graft survival to 19 days (P < 0.0005). Injection of YE1/48 mAb into presensitized Balb/c recipients did not significantly delay B6 skin graft rejection. On the other hand, after depleting recipient NK, NKT, and some cytotoxic T cells by injection of anti-asialo GM1, YE1/48 failed to prolong B6 skin graft survival in Balb/c recipients. The present studies indicate that injection of YE1/48 mAb significantly delays allogeneic skin graft rejection in nonsensitized recipients but not in sensitized recipients. The presence of NK, NKT cells, and some cytotoxic T cells may be essential for YE1/48-mediated immunosuppression in vivo.

Prolongation of allogeneic skin graft survival by injection of anti-Ly49A monoclonal antibody YE1/48.

It is well known that leukocyte composition, T cell phenotypes and immune function change in aged mice and humans. However, limited and conflicting results on the age-related immune changes in middle-aged mice were reported. Identification of the characteristics of allogeneic immune responses in aging mice may offer important information for transplantation immunology. The major age-related changes in the immune cell phenotypes and function of 12 months old mice include: 1) the significantly decreased CD4+ cell population in the peripheral blood, the major peripheral CD4+ cells is CD45RB(low)CD62L(low) memory phenotype; 2) the in vitro responses to alloantigens and Con A of splenocytes markedly reduced; 3) the in vivo secondary humoral immune responses to alloantigens significantly declined; 4) the age-related alteration in the thymus mainly occurred in CD4/CD8 double positive (DP) stage; and 5) increased CD80+ and MHC class II+ cell population in spleens. Thus, the major age-related immune changes in 12 months old mice occurred in CD4+ T cells in the periphery and DP stage in the thymus, which may subsequently lead to the decreased allogeneic immune responses and the different sensitivity to immunosuppressive drugs and treatments. Further studies on the characteristics of allogeneic immunity in aging individuals may help to determine the appropriated treatment for transplant aging individuals.

Altered allogeneic immune responses in middle-aged mice.

The ability of thymic epithelial cells (TEC) to re-educate mature T cells to be regulatory T cells has not been addressed. In the present study, this issue was directly investigated by co-culturing of mature T cells and allo-TECs. B6 macrophage cell line 1C21-cultured BALB/c splenocytes responded to B6 antigens in vitro. However, BALB/c splenocytes precultured with B6-derived TECs 1-4C18 or 1C6 did not proliferate to B6 antigens, but responded to rat antigens. Exogenous interleukin-2 (IL-2) failed to revise the unresponsiveness of these T cells. Allo-TEC-cultured T cells predominantly expressed Th2 cytokines (IL-4 and IL-10). B6 TEC-cultured BALB/c splenocytes markedly inhibited the immune responses of naïve BALB/c splenocytes to B6 antigens, but not to rat or the third-party mouse antigens. BALB/c nude mice that received naïve syngeneic splenocytes rejected B6 or rat skin grafts by 17 days postskin grafting; however, co-injection of B6 TEC-cultured BALB/c splenocytes significantly delayed B6 skin graft rejection (P < 0.01), with the unchanged rejection of rat skin grafts. These studies demonstrate that allo-TECs are able to 'educate' mature T cells to be regulatory cells, and suggest that regulatory cells derived from mature T cells by TECs may play an important role in T cell tolerance to allo- and auto-antigens.

Induction of regulatory T cells from mature T cells by allogeneic thymic epithelial cells in vitro.

Differentiation and proliferation of haematopoietic progenitor cells occur in intimate contact with the bone marrow microenvironment which is composed of stromal cells and extracellular matrix proteins. MOP3 (also known as brain and muscle Arnt-like protein-1, BMAL1), a master regulator of circadian rhythm, plays important roles in the regulation of cell differentiation and general physical functions. In the present studies, MOP3-deficient mice had significantly reduced levels of B cells in the peripheral blood, spleen and bone marrow compared MOP3(+/-) or MOP3(+/+) littermates. Flow cytometry analysis showed the levels of pre-B cells in bone marrow of MOP3(-/-) mice were similar as that in control mice. Adoptive transfer of MOP3(-/-) bone marrow cells (BMC) to lethally irradiated BALB/c Rag2(-/-) recipients, normal T and B cell development was observed, whereas Adoptive transfer of BALB/c BMC to lethally irradiated MOP3(-/-) recipients, B-cell development was significantly impaired. These results presented herein with MOP3-deficient mice reveal the involvement of MOP3 in the development of B cells, but not other immune cells. The effect of MOP3 on the differentiation of pre-B cells to mature B cells might be mediated by the bone marrow microenvironment. This study also showed a connection between a master regular of circadian rhythm with B-cell development in mice.

MOP3, a component of the molecular clock, regulates the development of B cells.

To identify a noninvasive screening test for intestinal allograft monitoring.

Calprotectin: a novel noninvasive marker for intestinal allograft monitoring.

Reactive oxygen species (ROS) are increased in human abdominal aortic aneurysms (AAA). NADPH oxidases are the predominant source of superoxide anion (O(2)(-)) in the vasculature. Inducible nitric oxide synthase (iNOS) produces a significant amount of nitric oxide (NO) during inflammatory processes. We hypothesized that ROS produced by NADPH oxidases and iNOS played an important role in aneurysm formation. We examined this hypothesis using selective blockade of NADPH oxidases and iNOS in a murine model of AAA. Mice, including C57BL/6, iNOS knockout (iNOS(-/-)) mice, and its background matched control (C57BL/6), underwent AAA induction by periaortic application of CaCl(2). Aortic diameter was measured at aneurysm induction and harvest. Beginning 1 week prior to aneurysm induction and continuing to aortic harvest 6 weeks later, one group of the C57BL/6 mice were treated with orally administered apocynin (NADPH oxidase inhibitor). Control mice were given water. The mean diameter and change in diameter of each group were compared with concurrent controls. Aortic levels of the NO metabolite, NO(x) (NO(2) and NO(3)), were significantly increased in CaCl(2)-treated wild type mice. INOS(-/-) mice were partly resistant to aneurysm induction. This was associated with reduced expression of matrix metalloproteinase (MMP)-2 and MMP-9 and decreased production of NO(x) in the aortic tissues. Inhibition of NADPH oxidase by apocynin also blocked aneurysm formation. In conclusion, both iNOS deficiency and NADPH oxidase inhibition suppressed aneurysm formation in association with decreased NO(x) levels. These studies suggest that both NADPH oxidase and iNOS pathways contribute to ROS production and AAA development.

Inhibition of reactive oxygen species attenuates aneurysm formation in a murine model.

Small bowel transplantation provides a potentially life-saving treatment of severe intestinal failure. Lack of a noninvasive marker of disease makes diagnosis of rejection dependent on frequent endoscopy and biopsy. We hypothesized that increased plasma nitrite and nitrate (NOx) levels measured after small bowel transplant would be associated with abnormal final pathology.

Plasma nitrite and nitrate levels as a noninvasive marker of pathology after human small bowel transplantation.

Small intestine transplantation is the only life-saving therapy available for patients with intestinal failure and life-threatening complications of parenteral nutrition, but it is still plagued by high levels of early acute rejection. The ability to diagnose rejection noninvasively, ideally before pathologic manifestations, would be a major advance in the care of intestinal transplant patients.

Stool calprotectin monitoring after small intestine transplantation.

Human-specific HIV-1 and hepatitis co-infections significantly affect patient management and call for new therapeutic options. Small xenotransplantation models with human hepatocytes and hematolymphoid tissue should facilitate antiviral/antiretroviral drug trials. However, experience with mouse strains tested for dual reconstitution is limited, with technical difficulties such as risky manipulations with newborns and high mortality rates due to metabolic abnormalities. The best animal strains for hepatocyte transplantation are not optimal for human hematopoietic stem cell (HSC) engraftment, and vice versa. We evaluated a new strain of highly immunodeficient nonobese diabetic/Shi-scid (severe combined immunodeficiency)/IL-2Rγc(null) (NOG) mice that carry two copies of the mouse albumin promoter-driven urokinase-type plasminogen activator transgene for dual reconstitution with human liver and immune cells. Three approaches for dual reconstitution were evaluated: i) freshly isolated fetal hepatoblasts were injected intrasplenically, followed by transplantation of cryopreserved HSCs obtained from the same tissue samples 1 month later after treosulfan conditioning; ii) treosulfan conditioning is followed by intrasplenic simultaneous transplantation of fetal hepatoblasts and HSCs; and iii) transplantation of mature hepatocytes is followed by mismatched HSCs. The long-term dual reconstitution was achieved on urokinase-type plasminogen activator-NOG mice with mature hepatocytes (not fetal hepatoblasts) and HSCs. Even major histocompatibility complex mismatched transplantation was sustained without any evidence of hepatocyte rejection by the human immune system. 

Human hepatocytes and hematolymphoid dual reconstitution in treosulfan-conditioned uPA-NOG mice.

Alcohol consumption exacerbates the course of hepatitis C viral (HCV) infection, worsens outcomes and contributes to the development of chronic infection that exhibits low anti-viral treatment efficiency. The lack of suitable in vivo models makes HCV-ethanol studies very difficult. Here, we examine whether chimeric SCID Alb-uPA mice transplanted with human hepatocytes and infected with HCV develop worsening pathology when fed ethanol. After 5 weeks of feeding, such mice fed chow+water (control) or chow+20% ethanol in water (EtOH) diets mice developed oxidative stress, decreased proteasome activity and increased steatosis. Importantly, HCV(+) mice in the control group cleared HCV RNA after 5 weeks, while the infection persisted in EtOH-fed mice at the same or even higher levels compared with pre-feeding HCV RNA. We conclude that in chimeric SCID Alb-uPA mice, EtOH exposure causes the complex biochemical and histological changes typical for alcoholic liver injury. In addition, ethanol feeding delays the clearance of HCV RNA thereby generating persistent infection and promoting liver injury. Overall, this model is appropriate for conducting HCV-ethanol studies.

Ethanol affects hepatitis C pathogenesis: humanized SCID Alb-uPA mouse model.

Alcohol-induced progression of hepatitis C virus (HCV) infection is related to dysfunction of innate immunity in hepatocytes. Endogenously produced interferon (IFN)α induces activation of interferon-stimulated genes (ISGs) via triggering of the Janus kinase-signal transducer and activator of transcription 1 (STAT1) pathway. This activation requires protein methyltransferase 1-regulated arginine methylation of STAT1. Here, we aimed to study whether STAT1 methylation also depended on the levels of demethylase jumonji domain-containing 6 protein (JMJD6) and whether ethanol and HCV affect JMJD6 expression in hepatocytes.

Yimin Sun

School of Architecture

South China University of Technology

Establishment of the Dual Humanized TK-NOG Mouse Model for HIV-associated Liver Pathogenesis

Study on the Moisture Absorption and Desorption Rate of Bamboo Scrimber in a Hot-Humid Climatic Wind Tunnel

Yimin Sun

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}School of Architecture

South China University of Technology

Establishment of the Dual Humanized TK-NOG Mouse Model for HIV-associated Liver Pathogenesis

Study on the Moisture Absorption and Desorption Rate of Bamboo Scrimber in a Hot-Humid Climatic Wind Tunnel

School of Architecture