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Chikungunya virus (CHIKV) is an emerging/re-emerging mosquito-borne pathogen responsible for explosive epidemics of febrile illness characterized by debilitating polyarthralgia and the risk of lethal infection among the most severe cases. Despite the public health risk posed by CHIKV, no vaccine is currently available. Using a site-directed hydrogen peroxide-based inactivation approach, we developed a new CHIKV vaccine, HydroVax-CHIKV. This vaccine technology was compared to other common virus inactivation approaches including β-propiolactone (BPL), formaldehyde, heat, and ultraviolet (UV) irradiation. Heat, UV, and BPL were efficient at inactivating CHIKV-181/25 but caused substantial damage to neutralizing epitopes and failed to induce high-titer neutralizing antibodies in vaccinated mice. HydroVax-CHIKV and formaldehyde-inactivated CHIKV retained intact neutralizing epitopes similar to live virus controls but the HydroVax-CHIKV approach demonstrated a more rapid rate of virus inactivation. HydroVax-CHIKV vaccination induced high neutralizing responses to homologous and heterologous CHIKV clades as well as to other alphaviruses including Mayaro virus, O’nyong’nyong virus, and Una virus. Following heterologous infection with CHIKV-SL15649, HydroVax-CHIKV-immunized mice were protected against viremia, CHIKV-associated arthritic disease, and lethal CHIKV infection by an antibody-dependent mechanism. In contrast, animals vaccinated with Heat- or UV-inactivated virus showed no protection against viremia in addition to demonstrating significantly exacerbated CD4 + T cell-mediated footpad swelling after CHIKV infection. Together, these results demonstrate the risks associated with using suboptimal inactivation methods that fail to elicit protective neutralizing antibody responses and show that HydroVax-CHIKV represents a promising new vaccine candidate for prevention of CHIKV-associated disease.

Mayaro virus (MAYV) is a mosquito-transmitted alphavirus that causes debilitating and persistent arthritogenic disease. While MAYV was previously reported to infect non-human primates (NHP), characterization of MAYV pathogenesis is currently lacking. Therefore, in this study we characterized MAYV infection and immunity in rhesus macaques. To inform the selection of a viral strain for NHP experiments, we evaluated five MAYV strains in C57BL/6 mice and showed that MAYV strain BeAr505411 induced robust tissue dissemination and disease. Three male rhesus macaques were subcutaneously challenged with 10 5 plaque-forming units of this strain into the arms. Peak plasma viremia occurred at 2 days post-infection (dpi). NHPs were taken to necropsy at 10 dpi to assess viral dissemination, which included the muscles and joints, lymphoid tissues, major organs, male reproductive tissues, as well as peripheral and central nervous system tissues. Histological examination demonstrated that MAYV infection was associated with appendicular joint and muscle inflammation as well as presence of perivascular inflammation in a wide variety of tissues. One animal developed a maculopapular rash and two NHP had viral RNA detected in upper torso skin samples, which was associated with the presence of perivascular and perifollicular lymphocytic aggregation. Analysis of longitudinal peripheral blood samples indicated a robust innate and adaptive immune activation, including the presence of anti-MAYV neutralizing antibodies with activity against related Una virus and chikungunya virus. Inflammatory cytokines and monocyte activation also peaked coincident with viremia, which was well supported by our transcriptomic analysis highlighting enrichment of interferon signaling and other antiviral processes at 2 days post MAYV infection. The rhesus macaque model of MAYV infection recapitulates many of the aspects of human infection and is poised to facilitate the evaluation of novel therapies and vaccines targeting this re-emerging virus.

O’nyong-nyong virus (ONNV) is a mosquito-transmitted alphavirus identified in Uganda in 1959. The virus has potential for enzootic and urban transmission cycles, and in humans, ONNV infection manifests as fever, rash, and joint/muscle pain that can persist. There are currently no specific vaccines or antiviral treatments for ONNV. Since highly passaged alphaviruses often lose pathogenic features, we constructed an infectious clone for ONNV-UVRI0804 (ONNV 0804 ), a 2017 isolate from a febrile patient in Uganda. Viral replication for ONNV 0804 was compared to the highly passaged strain, ONNV UgMP30 , and ONNV UgMP30 replicated to higher levels in human dermal fibroblasts and Vero cells, but both viruses replicated similarly in C6/36 and mouse embryonic fibroblast cells. We performed a head-to-head comparison of in vivo virulence in both immunocompetent C57BL/6 mice and interferon deficient AG129 mice. In both mouse strains, ONNV 0804 was substantially more pathogenic than ONNV UgMP30 . Unlike ONNV UgMP30 , ONNV 0804 caused significant footpad swelling and broader tissue distribution with higher vRNA loads at both 5- and 43-days post-infection (dpi) relative to ONNV UgMP30 . This finding indicates that ONNV can persist in joint and muscle tissues for long periods of time, which has been associated with chronic arthritogenic human disease. In AG129 mice, ONNV 0804 caused a more rapid onset of disease, higher viremia, and a >800-fold increase in virulence. Previous studies have shown that CHIKV infection or vaccination can provide cross-reactive immunity to ONNV. To determine if a CHIKV vaccine can protect against the more virulent ONNV 0804 strain, we vaccinated mice with a hydrogen peroxide-inactivated CHIKV vaccine, HydroVax-CHIKV. Neutralizing antibody titers were determined against ONNV 0804 and CHIKV and animals were challenged with ONNV 0804 . An optimized two-dose vaccination regimen of HydroVax-CHIKV protected against lethal infection and reduced virus-associated arthritogenic disease. These data indicate that we have developed new and robust models for studying severe ONNV disease and that HydroVax-CHIKV vaccination can protect against infection with a highly pathogenic contemporary strain of ONNV.

Chikungunya virus (CHIKV) is a pathogenic arthritogenic alphavirus responsible for large-scale human epidemics for which a vaccine was recently approved for use. Mayaro virus (MAYV) is a related emerging alphavirus with epidemic potential with circulation overlap potential with CHIKV. We previously reported the ability of a non-replicating human adenovirus (AdV)-vectored vaccine expressing the MAYV structural polyprotein to protect against disease in mice following challenge with MAYV, CHIKV and UNAV. Herein, we evaluated mouse immunity and protective efficacy for an AdV-CHIKV full structural polyprotein vaccine in combination with heterologous AdV-MAYV prime/boost regimens versus vaccine coadministration. Heterologous prime/boost regimens skewed immunity toward the prime vaccine antigen but allowed for a boost of cross-neutralizing antibodies, while vaccine co-administration elicited robust, balanced responses capable of boosting. All immunization strategies protected against disease from homologous virus infection, but reciprocal protective immunity differences were revealed upon challenge with heterologous viruses. In vivo passive transfer experiments reproduced the inequity in reciprocal cross-protection after heterologous MAYV challenge. We detected in vitro antibody-dependent enhancement of MAYV replication, suggesting a potential mechanism for the lack of cross-protection. Our findings provide important insights into rational alphavirus vaccine design that may have important implications for the evolving alphavirus vaccine landscape.

Cytomegalovirus (CMV) establishes persistent, latent infection in hosts, causing diseases in immunocompromised patients, transplant recipients, and neonates. CMV infection modifies the host chemokine axis by modulating chemokine and chemokine receptor expression and by encoding putative chemokine and chemokine receptor homologues. The viral proteins have roles in cellular signaling, migration, and transformation, as well as viral dissemination, tropism, latency and reactivation. Herein, we review the contribution of CMV-encoded chemokines and chemokine receptors to these processes, and further elucidate the viral tropism role of rat CMV (RCMV) R129 and R131. These homologues of the human CMV (HCMV)-encoded chemokines UL128 and UL130 are of particular interest because of their dual role as chemokines and members of the pentameric entry complex, which is required for entry into cell types that are essential for viral transmission and dissemination. The contributions of UL128 and UL130 to acceleration of solid organ transplant chronic rejection are poorly understood, and are in need of an effective in vivo model system to elucidate the phenomenon. We demonstrated similar molecular entry requirements for R129 and R131 in the rat cells, as observed for HCMV, and provided evidence that R129 and R131 are part of the viral entry complex required for entry into macrophages, dendritic cells, and bone marrow cells.

Zika virus infection during pregnancy is associated with miscarriage and with a broad spectrum of fetal and neonatal developmental abnormalities collectively known as congenital Zika syndrome (CZS). Symptomology of CZS includes malformations of the brain and skull, neurodevelopmental delay, seizures, joint contractures, hearing loss and visual impairment. Previous studies of Zika virus in pregnant rhesus macaques (Macaca mulatta) have described injury to the developing fetus and pregnancy loss, but neonatal outcomes following fetal Zika virus exposure have yet to be characterized in nonhuman primates. Herein we describe the presentation of rhesus macaque neonates with a spectrum of clinical outcomes, including one infant with CZS-like symptoms including cardiomyopathy, motor delay and seizure activity following maternal infection with Zika virus during the first trimester of pregnancy. Further characterization of this neonatal nonhuman primate model of gestational Zika virus infection will provide opportunities to evaluate the efficacy of pre- and postnatal therapeutics for gestational Zika virus infection and CZS.

Effect of nitric oxide modulation on TGF-β1 and matrix proteins in chronic cyclosporine nephrotoxicity. Chronic cyclosporine (CsA) nephrotoxicity is characterized by interstitial fibrosis and afferent arteriolar hyalinosis. L-arginine (L-Arg), the substrate for nitric oxide (NO) synthase and N-nitro-L-arginine-methyl ester (L-NAME), the NO synthase inhibitor, were shown to modulate acute CsA nephrotoxicity. However, the mechanism of fibrosis in chronic CsA nephrotoxicity remains unclear. Thus, we examined the effect of NO modulation on fibrosis and the expression of transforming growth factor-β1 (TGF-β1) and matrix proteins in chronic CsA nephrotoxicity. Rats were administered CsA (7.5 mg/kg), CsA + L-Arg (1.7 g/kg), CsA + L-NAME (3.5 mg/kg), vehicle (VH), VH + L-Arg, and VH + L-NAME, and were sacrificed at 7 or 28 days. NO production, physiologic parameters, and histology were studied in addition to the mRNA expression of TGF-β1, plasminogen activator inhibitor-1 (PAI-1) and the matrix proteins biglycan and collagens type I and IV by Northern and the protein expression of PAI-1 and fibronectin by enzyme-linked immunosorbent assay. While L-NAME strikingly reduced NO biosynthesis and worsened the glomerular filtration rate and CsA-induced fibrosis, L-Arg had the opposite beneficial effect. In addition, the CsA-induced up-regulated expression of TGF-β1, PAI-1, and the matrix proteins biglycan, fibronectin, and collagen I was significantly increased with L-NAME and strikingly improved with L-Arg. Collagen IV expression was not affected. Also, NO modulation did not affect VH-treated rats. Chronic CsA nephrotoxicity can be aggravated by NO blockade and ameliorated by NO enhancement, suggesting that NO maintains a protective function. NO modulation was associated with a change in TGF-β1 expression, which, in turn, was associated with alterations in matrix deposition and matrix degradation through its effect on PAI-1.

Sirolimus increases transforming growth factor-β1 expression and potentiates chronic cyclosporine nephrotoxicity. Sirolimus (SRL) is increasingly being used to decrease cyclosporine (CsA) exposure. SRL is not known to be nephrotoxic and has a mechanism of action distinct from CsA. We investigated the effect of combining CsA and SRL on renal structure and function and on transforming growth factor-β1 (TGF-β1) and extracellular matrix (ECM) proteins in a model of chronic CsA nephrotoxicity. Rats treated with vehicle, SRL 0.3mg/kg/day, CsA 5 or 10mg/kg/day, or CsA5+SRL were sacrificed at 7 or 28days. Physiologic and histologic changes were studied in addition to TGF-β1 mRNA and protein expressions, and mRNA expression of plasminogen activator inhibitor-1 (PAI-1) and ECM proteins biglycan and types I and IV collagen. While SRL alone did not alter renal function and structure, it potentiated the nephrotoxic actions of CsA when used in combination with low-dose CsA5 and resulted in significant changes similar to high-dose CsA10. In addition, SRL alone increased TGF-β1 by 44% to 49% (P < 0.05 vs. VH). When used in combination with low-dose CsA5, SRL potentiated TGF-β1 mRNA and protein by 121% and 176%, respectively (P < 0.05 vs. VH and CsA5), to levels achieved with high-dose CsA10. The expression of the ECM proteins followed that of TGF-β1; a similar effect was observed with PAI-1, suggesting a decrease in ECM degradation. Because SRL augments nephrotoxicity, caution should be exercised when it is used in combination with CsA. More studies are needed to determine the long-term clinical impact of SRL on nephrotoxicity and allograft function.

Background/Aims: Ischemia reperfusion injury in the early posttransplant period affects immediate graft function and late allograft dysfunction. Recently, we showed that pharmacologic preconditioning with a calcineurin inhibitor improved transplant outcomes in rat syngeneic kidney transplantation. There is also evidence that cellular cholesterol content increases after many types of renal injury. Methods: In this study, we looked at the effect of cyclosporine (CsA) on the donor kidney free cholesterol (FC) content in this model. Donor rats were pretreated with one dose of CsA 10 mg/kg administered 24 h or 7 days before being subjected to 2 h cold ischemia and then transplanted. Results: Pharmacologic preconditioning with CsA significantly improved renal function and histology and increased donor kidney FC content. On the other hand, fluvastatin co-administration with CsA abrogated that beneficial effect in association with a decrease in donor kidney FC content. Conclusion: CsA preconditioning leads to better outcomes in kidney transplantation and is associated with up-regulation of renal FC content. The latter may then contribute to acquired cytoresistance, possibly by stabilizing the plasma membrane. Thus, use of statins around the time of transplantation may need to be evaluated until further studies are conducted to determine the clinical relevance of this observation.

Nitric oxide modulates vascular endothelial growth factor and receptors in chronic cyclosporine nephrotoxicity. Vascular endothelial growth factor (VEGF) is involved in angiogenesis, wound healing, and inflammation and exerts its effect via tyrosine kinase receptors, fms-like tyrosine kinase (Flt-1) and fetal liver kinase (Flk-1 or KDR). We have previously shown that VEGF is up-regulated in a model of chronic cyclosporine (CsA) nephrotoxicity and that l-arginine (l-Arg) improved while N-nitro-l-arginine-methyl ester (L-NAME) worsened fibrosis. We examined the role of nitric oxide modulation on VEGF in this model. Pair-fed salt-depleted rats were administered CsA, CsA + L-NAME, CsA +l-Arg, vehicle (VH), VH + L-NAME or VH +l-Arg and were sacrificed at 7 or 28 days. Physiologic and histologic changes were studied in addition to the mRNA expression of VEGF and its receptors Flt-1 and KDR/Flk-1 by Northern blot and the protein expression of VEGF by Western blot and immunohistochemical staining. While L-NAME worsened renal function and histology, l-Arg had the opposite beneficial effect in CsA-treated rats. VEGF mRNA and protein expressions increased with CsA, further increased with L-NAME and became significantly reduced with L-Arg. Flt-1 expression was similar in all groups. On the other hand, KDR/Flk-1 mRNA expression was modulated in a fashion similar to VEGF. Also, nitric oxide modulation did not have an effect on VH-treated rats. VEGF expression in chronic CsA nephrotoxicity is increased by nitric oxide blockade and decreased by nitric oxide enhancement. Moreover, VEGF probably exerted its effect via the KDR/Flk-1 receptor. The actions of VEGF in this model remain speculative, but it is probable that VEGF plays a role, either independently or through nitric oxide, in CsA-induced fibrosis.