Shimmura Shigeto

PURPOSE: This study explores the application of adipose-derived mesenchymal stromal cells (adMSCs) as a therapy for ocular inflammatory diseases utilizing a chronic GVHD model. METHODS: Human adMSCs were administered via subconjunctival injection into mice with chronic ocular GVHD. Clinical scores and changes in T cell populations were analyzed. RESULTS: The study showed significant improvement in corneal integrity, including epithelial damage, opacity, thickness, and structure, after subconjunctival adMSC transplantation. Additionally, adMSC transplantation increased CD45+ and Foxp3+ Tregs while decreasing CD4+ T cells, 1IL17A+ Th17 cells, and IFNγ+ Th1 cells in local cervical lymph nodes. Moreover, adMSC-conditioned media enhanced wound closure and cell migration toward the wound bed in vitro. The cells disappeared within a week suggesting that trophic factors were involved. CONCLUSION: The dual benefit of adMSCs in immune-related ocular disorders underscores their potential for clinical application. This study focuses on subconjunctival delivery, effects of adMSCs and migration post-injection, with implications for optimizing cellular therapy application. The observed dual action, combining immunomodulation and tissue repair enhancement, underscores holistic approach of adMSC therapy in regenerative medicine, making it a potent treatment for diseases involving inflammation and tissue damage in the ocular surface.

PURPOSE: Aging is a well-established risk factor for meibomian gland dysfunction (MGD). We previously reported an accelerated cellular senescence phenomenon in the lacrimal glands of a murine model of chronic graft-versus-host disease (cGVHD). Herein, we aimed to elucidate the relationship between cellular senescence and MGD in cGVHD mice, utilizing the senolytic agent ABT-263. METHODS: A cGVHD mouse model was established through allogeneic bone marrow transplantation (BMT) from B10.D2 to BALB/c mice. Subsequently, cGVHD mice were treated with either ABT-263 or vehicle. The eyelids of recipients were analyzed at 4-week intervals post-BMT in both groups. RESULTS: Meibomian gland (MG) area was significantly smaller in cGVHD mice than in syngeneic control mice. ABT-263-treated mice retained a significantly larger MG area than their vehicle-treated counterparts. Pathological and immunohistochemical examinations revealed significant reductions in eyelid tissue inflammation and pathological fibrosis in the ABT-263 group compared to that in the vehicle-treated group. Additionally, expression of DNA damage markers, senescent cell markers, and senescence-associated secretory phenotype (SASP) factors was elevated in the eyelids of cGVHD mice compared with that in syngeneic mice. The expression of these cellular senescence-associated molecules was considerably suppressed in ABT-263-treated eyelids compared to that in vehicle-treated ones. CONCLUSIONS: Cellular senescence, along with expression of SASP factors, exhibited increased activity in the eyelids, particularly in the MGs of cGVHD mice. ABT-263 mitigated the severity of MGD. These findings highlight the potential of targeting cellular senescence as an effective approach for MGD treatment in cGVHD.

Regenerative medicine is a highly anticipated field with hopes to provide cures for previously uncurable diseases such as spinal cord injuries and retinal blindness. Most regenerative medical products use either autologous or allogeneic stem cells, which may or may not be genetically modified. The introduction of induced-pluripotent stem cells (iPSCs) has fueled research in the field, and several iPSC-derived cells/tissues are currently undergoing clinical trials. The cornea is one of the pioneering areas of regenerative medicine, and already four cell therapy products are approved for clinical use in Japan. There is one other government-approved cell therapy product approved in Europe, but none are approved in the USA at present. The cornea is transparent and avascular, making it unique as a target for stem cell therapy. This review discusses the unique properties of the cornea and ongoing research in the field.

Recently, the murine cornea has reemerged as a robust stem cell (SC) model, allowing individual SC tracing in living animals. The cornea has pioneered seminal discoveries in SC biology and regenerative medicine, from the first corneal transplantation in 1905 to the identification of limbal SCs and their transplantation to successfully restore vision in the early 1990s. Recent experiments have exposed unexpected properties attributed to SCs and progenitors and revealed flexibility in the differentiation program and a key role for the SC niche. Here, we discuss the limbal SC model and its broader relevance to other tissues, disease, and therapy.

INTRODUCTION: Fuchs endothelial corneal dystrophy (FECD) is the leading cause of corneal blindness in developed countries. Corneal endothelial cells in FECD are susceptive to oxidative stress, leading to mitochondrial dysfunction and cell death. Oxidative stress causes many forms of cell death including parthanatos, which is characterized by translocation of apoptosis-inducing factor (AIF) to the nucleus with upregulation of poly (ADP-ribose) polymerase 1 (PARP-1) and poly (ADP-ribose) (PAR). Although cell death is an important aspect of FECD, previous reports have often analyzed immortalized cell lines, making the evaluation of cell death difficult. Therefore, we established a new in vitro FECD model to evaluate the pathophysiology of FECD. METHODS: Corneal endothelial cells were derived from disease-specific induced pluripotent stem cells (iPSCs). Hydrogen peroxide (H2O2) was used as a source for oxidative stress to mimic the pathophysiology of FECD. We investigated the responses to oxidative stress and the involvement of parthanatos in FECD-corneal endothelial cells. RESULTS: Cell death ratio and oxidative stress level were upregulated in FECD with H2O2 treatment compared with non-FECD control, indicating the vulnerability of oxidative stress in FECD. We also found that intracellular PAR, as well as PARP-1 and AIF in the nucleus were upregulated in FECD. Furthermore, PARP inhibition, but not pan-caspase inhibition, rescued cell death, DNA double-strand breaks, mitochondrial membrane potential depolarization and energy depletion, suggesting that cell death was mainly due to parthanatos. CONCLUSIONS: We report that parthanatos may be involved in the pathophysiology of FECD and targeting this cell death pathway may be a potential therapeutic approach for FECD.