Mitochondria Transplantation Promotes Corneal Epithelial Wound Healing.

Purpose: The integrity of the corneal epithelium is essential in maintaining normal corneal function. Conditions disrupting the corneal epithelial layer range from chemical burns to dry eye disease and may result in impairment of both corneal transparency and sensation. Identifying factors that regulate corneal wound healing is key for the development of new treatment strategies. Here, we investigated a direct role of mitochondria in corneal wound healing via mitochondria transplantation. Methods: Human corneal epithelial cells (hCECs) were isolated from human corneas and incubated with mitochondria which were isolated from human ARPE-19 cells. We determined the effect of mitochondria transplantation on wound healing and proliferation of hCECs. In vivo, we used a mouse model of corneal chemical injury. Mitochondria were isolated from mouse livers and topically applied to the ocular surface following injury. We evaluated the time of wound repair, corneal re-epithelization, and stromal abnormalities. Results: Mitochondria transplantation induced the proliferation and wound healing of primary hCECs. Further, mitochondria transplantation promoted wound healing in vivo. Specifically, mice receiving mitochondria recovered twice as fast as control mice following corneal injury, presenting both enhanced and improved repair. Corneas treated with mitochondria demonstrated the re-epithelization of the wound area to a multi-layer appearance, compared to thinning and complete loss of the epithelium in control mice. Mitochondria transplantation also prevented the thickening and disorganization of the corneal stromal lamella, restoring normal corneal dehydration. Conclusions: Mitochondria promote corneal re-epithelization and wound healing. Augmentation of mitochondria levels via mitochondria transplantation may serve as an effective treatment for inducing the rapid repair of corneal epithelial defects.

Computational analysis of super-resolved in situ sequencing data reveals genes modified by immune-tumor contact events.

Cancer cells can manipulate immune cells and escape from the immune system response. Quantifying the molecular changes that occur when an immune cell touches a tumor cell can increase our understanding of the underlying mechanisms. Recently, it became possible to perform such measurements in situ-for example, using expansion sequencing, which enabled in situ sequencing of genes with super-resolution. We systematically examined whether individual immune cells from specific cell types express genes differently when in physical proximity to individual tumor cells. First, we demonstrated that a dense mapping of genes in situ can be used for the segmentation of cell bodies in 3D, thus improving our ability to detect likely touching cells. Next, we used three different computational approaches to detect the molecular changes that are triggered by proximity: differential expression analysis, tree-based machine learning classifiers, and matrix factorization analysis. This systematic analysis revealed tens of genes, in specific cell types, whose expression separates immune cells that are proximal to tumor cells from those that are not proximal, with a significant overlap between the different detection methods. Remarkably, an order of magnitude more genes are triggered by proximity to tumor cells in CD8 T cells compared to CD4 T cells, in line with the ability of CD8 T cells to directly bind major histocompatibility complex (MHC) class I on tumor cells. Thus, in situ sequencing of an individual biopsy can be used to detect genes likely involved in immune-tumor cell-cell interactions. The data used in this manuscript and the code of the InSituSeg, machine learning, cNMF, and Moran's I methods are publicly available at doi:10.5281/zenodo.7497981.

CD74 is a regulator of hematopoietic stem cell maintenance.

Hematopoietic stem and progenitor cells (HSPCs) are a small population of undifferentiated cells that have the capacity for self-renewal and differentiate into all blood cell lineages. These cells are the most useful cells for clinical transplantations and for regenerative medicine. So far, it has not been possible to expand adult hematopoietic stem cells (HSCs) without losing their self-renewal properties. CD74 is a cell surface receptor for the cytokine macrophage migration inhibitory factor (MIF), and its mRNA is known to be expressed in HSCs. Here, we demonstrate that mice lacking CD74 exhibit an accumulation of HSCs in the bone marrow (BM) due to their increased potential to repopulate and compete for BM niches. Our results suggest that CD74 regulates the maintenance of the HSCs and CD18 expression. Its absence leads to induced survival of these cells and accumulation of quiescent and proliferating cells. Furthermore, in in vitro experiments, blocking of CD74 elevated the numbers of HSPCs. Thus, we suggest that blocking CD74 could lead to improved clinical insight into BM transplant protocols, enabling improved engraftment.

Comprehensive single institute experience with melanoma TIL: Long term clinical results, toxicity profile, and prognostic factors of response.

Adoptive cell transfer (ACT) of tumor-infiltrating lymphocytes (TIL) mediates objective responses in 30% to 50% of patients with metastatic melanoma according to multiple, small phase 2 trials. Here we report the long-term clinical results, intent-to-treat analysis, predictors of response and toxicity profile in a large patient cohort. A total of 179 refractory melanoma patients were enrolled in the ACT trial. TIL were administered in combination with high-dose bolus interleukin-2 following preconditioning with cyclophosphamide and fludarabine. Patients were followed-up for a median of 7.2 years. A total of 107 (60%) of 179 enrolled patients were treated. The main reason for the drop out of the study was clinical deterioration. Of 103 evaluated patients, 29 patients (28%) achieved an objective response (OR), including complete remission (8%) or partial response (20%). Sixteen pateints exhibited stable disease. Predictors of response were performance status, time of TIL in culture and CD8 frequency in the infusion product. The absolute lymphocyte count 1 and 2 weeks after TIL infusion was the most predictive parameter of response. With a medium follow-up time of 7.2 years, OR patients reached a median overall survival (OS) of 58.45 months and a median progression-free survival (PFS) of 15.43 months, as compared with nonresponders, with 6.73 months OS and 2.60 months PFS. By 6 years, 50% of OR patients were alive and 43% had no documented progression. TIL ACT can yield durable objective responses, even as salvage therapy in highly advanced metastatic melanoma patients.

Head-to-head comparison of in-house produced CD19 CAR-T cell in ALL and NHL patients.

BACKGROUND: CD19 chimeric antigen receptor T (CAR-T) cells demonstrate remarkable remission rates in pediatric and adult patients with refractory or relapsed (r/r) acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphoma (NHL). In 2016, we initiated a clinical trial with in-house produced CD19 CAR-T cells with a CD28 co-stimulatory domain. We analyzed, for the first time, differences in production features and phenotype between ALL and NHL patients. METHODS: Non-cryopreserved CAR-T cells were produced from patients' peripheral blood mononuclear cells within 9 to 10 days. 93 patients with r/r ALL and NHL were enrolled under the same study. CAR-T cells of ALL and NHL patients were produced simultaneously, allowing the head-to-head comparison. RESULTS: All patients were heavily pretreated. Three patients dropped out from the study due to clinical deterioration (n=2) or production failure (n=1). Cells of ALL patients (n=37) expanded significantly better and contained more CAR-T cells than of NHL patients (n=53). Young age had a positive impact on the proliferation capacity. The infusion products from ALL patients contained significantly more naïve CAR-T cells and a significantly higher expression of the chemokine receptor CXCR3. PD-1, LAG-3, TIM-3, and CD28 were equally expressed. 100% of ALL patients and 94% of NHL patients received the target dose of 1×10e6 CAR-T/kg. The overall response rate was 84% (30/36) in ALL and 62% (32/52) in NHL. We further compared CAR-T cell infusion products to tumor infiltrating lymphocytes (TIL), another common type of T cell therapy, mainly clinically effective in solid tumors. CAR-T cells contained significantly more naïve T cells and central memory T cells and significantly less CCR5 compared to TIL infusion products. CONCLUSIONS: The in-house production of CAR-T cells is highly efficient and fast. Clinical response rate is high. CAR-T cells can be successfully produced for 99% of patients in just 9 to 10 days. Cells derived from ALL patients demonstrate a higher proliferation rate and contain higher frequencies of CAR-T cells and naïve T cells than of NHL patients. In addition, understanding the differences between CAR-T and TIL infusion products, may provide an angle to develop CAR-T cells for the treatment of solid tumors in the future. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov; CAR-T: NCT02772198, First posted: May 13, 2016; TIL: NCT00287131, First posted: February 6, 2006.

Genetic Modification of Tumor-Infiltrating Lymphocytes via Retroviral Transduction.

Adoptive T cell therapy (ACT) holds great promise for cancer treatment. One approach, which has regained wide interest in recent years, employs antitumor T cells isolated from tumor lesions ("tumor-infiltrating lymphocytes" or TIL). It is now appreciated that a considerable proportion of anti-melanoma TIL recognize new HLA-binding peptides resulting from somatic mutations, which occurred during tumor progression. The clinical efficacy of TIL can potentially be improved via their genetic modification, designed to enhance their survival, homing capacity, resistance to suppression, tumor killing ability and additional properties of clinical relevance. Successful implementation of such gene-based strategies critically depends on efficient and reproducible protocols for gene delivery into clinical TIL preparations. Here we describe an optimized protocol for the retroviral transduction of TIL. As the experimental system we employed anti-melanoma TIL cultures prepared from four patients, recombinant retrovirus encoding an anti-CD19 chimeric antigen receptor (CAR) as a model gene of interest and CD19+ and CD19- human cell lines serving as target cells. Transduction on day 7 of the rapid expansion protocol (REP) resulted in 69 ± 8% CAR positive TIL. Transduced, but not untransduced TIL, from the four patients responded robustly to CD19+, but not CD19- cell lines, as judged by substantial secretion of IFN-γ following co-culture. In light of the rekindled interest in antitumor TIL, this protocol can be incorporated into a broad range of gene-based approaches for improving the in-vivo survival and functionality of TIL in the clinical setting.