New approaches in viraemic organ transplantation and antiviral therapies

Ex vivo anchored PD-L1 functionally prevent in vivo renal allograft rejection

Organ transplantation is the optimal treatment for patients with end-stage diseases. T cell activation is a major contributing factor toward the trigger of rejection. Induction therapy with T cell depleting agent is a common option but increases the risk of severe systemic infections. The ideal therapy should precisely target the allograft. Here, we developed a membrane-anchored-protein PD-L1 (map-PD-L1), which effectively anchored onto the surface of rat glomerular endothelial cells (rgEC). The expression of PD-L1 increased directly with map-PD-L1 concentration and incubation time. Moreover, map-PD-L1 was even stably anchored to rgEC at low temperature. Map-PD-L1 could bind to PD-1 and significantly promote T cell apoptosis and inhibited T cell activation. Using kidney transplantation models, we found that ex vivo perfusion of donor kidneys with map-PD-L1 significantly protected grafts against acute injury without using any immunosuppressant. We found map-PD-L1 could reduce T cell graft infiltration and increase intragraft Treg infiltration, suggesting a long-term effect in allograft protection. More importantly, modifying donor organs in vitro was not only safe, but also significantly reduced the side effects of systemic application. Our results suggested that ex vivo perfusion of donor organ with map-PD-L1 might provide a viable clinical option for organ-targeted induction therapy in organ transplantation.

Progress, evolving therapeutic/diagnostic approaches, and challenges in the management of hepatitis C virus infections

Hepatitis C virus (HCV) infections are emerging as one of the foremost challenges in healthcare owing to its chronicity and the virus's quasispecies nature. Worldwide, over 170 million people are chronically infected with HCV, with an annual mortality of over 500,000 people across the world. The emerging pathophysiological evidence links HCV infections to a risk of developing liver diseases such as cirrhosis and hepatocellular carcinoma. Despite the great strides that have been made towards understanding the pathophysiology of disease progression, the tailored treatments of HCV infection remain to be established. The present review provides an update of the literature pertaining to evolving therapeutic approaches and prophylactic measures for the effective management of HCV infections. An extensive discussion of established and experimental immune prophylactic measures also sheds light on current developments in the design of vaccination strategies against HCV infection. We have also attempted to address the application of nanotechnology in formulating effective therapeutic interventions against HCV. Pointing out the limitations of the existing diagnostic methods and therapeutic approaches against HCV might inspire the design and development of novel, efficient, reliable, and cost-effective diagnostic technologies as well as novel therapeutic and immune prophylactic interventions for the effective management of HCV.

Targeting peripheral immune organs with self-assembling prodrug nanoparticles ameliorates allogeneic heart transplant rejection

Organ transplantation has become a mainstay of therapy for patients with end-stage organ diseases. However, long-term administration of immunosuppressive agents, a scheme for improving the survival of transplant recipients, has been compromised by severe side effects and posttransplant complications. Therapeutic delivery targeting immune organs has the potential to address these unmet medical issues. Here, through screening of a small panel of mammalian target of rapamycin complex kinase inhibitor (TORKinib) compounds, a TORKinib PP242 is identified to be able to inhibit T cell function. Further chemical derivatization of PP242 using polyunsaturated fatty acids (i.e., docosahexaenoic acid) transforms this water-insoluble hydrophobic agent into a self-assembling nanoparticle (DHA-PP242 nanoparticle [DPNP]). Surface PEGylation of DPNP with amphiphilic copolymers renders the nanoparticles aqueously soluble for preclinical studies. Systemically administered DPNP shows tropism for macrophages within peripheral immune organs. Furthermore, DPNP regulates differentiation of adoptively transferred T cells in a macrophage-dependent manner in Rag1-/- mouse model. In an experimental model of heart transplantation, DPNP significantly extends the survival of grafts through inducing immune suppression, thus reducing the inflammatory response of the recipients. These findings suggest that targeted delivery of TORKinibs exploiting prodrug-assembled nanoparticle scaffolds may provide a therapeutic option against organ rejection.