Biology subjects

Park, J. A.

Publications and source records attributed to Park, J. A..

3 recordsLinked to original sources

bioRxiv2024

Neuron-derived Prox1 suppresses injury-induced reprogramming of Muller glia to proliferative retinal progenitor cells

Individuals with retinal degenerative diseases face significant obstacles in restoring normal vision due to the inability to regenerate degenerated retinal cells. While retinal neurons can be regenerated from Muller glia (MG) in cold-blooded vertebrates, this regenerative ability is lacking in mammals, indicating the limited competence of mammalian MG for retinal regeneration. In this study, we elucidate the role of prospero-related homeobox 1 (Prox1) in rendering the mammalian retina incompetent for MG-derived regeneration. Prox1 accumulates in MG in the degenerating human and mouse retinas but not in those in the regenerating zebrafish retina. Strikingly, Prox1 in mouse MG originated from neighboring retinal neurons through intercellular protein transfer. Consequently, inhibition of Prox1 transfer to MG enables the reprogramming of MG into proliferative retinal progenitor cells in injured mouse retinas. Furthermore, we succeeded in regenerating retinal neurons and delaying vision loss in retinitis pigmentosa disease model in mice by adenoassociated viral gene delivery of an anti-Prox1 antibody that sequesters extracellular Prox1 in the mouse retina. Taken together, our findings highlight the therapeutic potential of anti-Prox1 therapy in restoring the regenerative potential of the mammalian retina.

developmental biology↗

bioRxiv2021

Overcoming Tumor Heterogeneity by Ex Vivo Arming of T Cells Using Multiple Bispecific Antibodies

PurposeTumoral heterogeneity is a hallmark of tumor evolution and cancer progression, being a longstanding challenge to targeted immunotherapy. Ex vivo armed T cells (EATs) using IgG-[L]- scFv bispecific antibodies (BsAbs) are potent tumor-specific cytotoxic effectors. To improve the anti-tumor efficacy of EATs against heterogeneous solid tumors, we explored multi-antigen targeting approaches. MethodsEx vivo expanded T cells were armed with BsAbs built on the IgG-[L]-scFv platform, where an anti-CD3 (huOKT3) scFv was attached to the carboxyl end of both light chains of a tumor specific IgG. Multispecificity was created by combining monospecific EATs, combining BsAbs on the same T cell, or combining specificities on the same antibody. Three multi-antigens targeting EAT strategies were tested: (1) pooled EATs (simultaneous combination of monospecific EATs or alternate EATs (alternating combination of monospecific EATs), (2) dual-EATs or multi- EATs (T cells simultaneously armed with [≥] 2 BsAbs), and (3) TriAb-EATs [T cells armed with BsAb specific for two tumor targets besides CD3 (TriAb)]. The properties and efficiencies of these 3 strategies were evaluated by flow cytometry, in vitro cytotoxicity, cytokine release assays, and in vivo studies performed in BALB-Rag2-/-IL-2R-{gamma}c-KO (BRG) mice xenografted with cancer cell line (CDX) or patient-derived tumor (PDX). ResultsMulti-EATs retained target antigen specificity and anti-tumor potency. Cytokine release with multi-EATs in the presence of tumor cells was substantially less than when multiple BsAbs were mixed with unarmed T cells. When tested against CDXs or PDXs, dual- or multi-EATs effectively suppressed tumor growth without clinical toxicities. Most importantly, dual- or multi- EATs were highly efficient in preventing clonal escape while mono- or TriAb- EATs were not as efficient. ConclusionArming T cells with multiple BsAbs enabled multi-specific T cell immunotherapy which overcomes tumor heterogeneity without excessive cytokine release.

cancer biology↗

bioRxiv2021

Homogenization of a Reaction Diffusion Equation can Explain Influenza A Virus Load Data

We study the influence of spatial heterogeneity on the antiviral activity of mouse embryonic fibroblasts (MEF) infected with influenza A. MEF of type Ube1L-/- are composed of two distinct sub-populations, the strong type that sustains a strong viral infection and the weak type, sustaining a weak viral load. We present new data on the virus load infection of Ube1L-/-, which have been micro-printed in a checker board pattern of different sizes of the inner squares. Surprisingly, the total viral load at one day after inoculation significantly depends on the sizes of the inner squares. We explain this observation by using a reaction diffusion model and we show that mathematical homogenization can explain the observed inhomogeneities. If the individual patches are large, then the growth rate and the carrying capacity will be the arithmetic means of the patches. For finer and finer patches the average growth rate is still the arithmetic mean, however, the carrying capacity uses the harmonic mean. While fitting the PDE to the experimental data, we also predict that a discrepancy in virus load would be unobservable after only half a day. Furthermore, we predict the viral load in different inner squares that had not been measured in our experiment and the travelling distance the virions can reach after one day.

microbiology↗