Analysis of Allogenicity of Mesenchymal Stem Cells in Engraftment and Wound Healing in Mice

Studies have shown that allogeneic (allo-) bone marrow derived mesenchymal stem cells (BM-MSCs) may enhance tissue repair/regeneration. However, recent studies suggest that immune rejection may occur to allo-MSCs leading to reduced engraftment. In this study, we compared allo-BM-MSCs with syngeneic BM-MSCs or allo-fibroblasts in engraftment and effect in wound healing. Equal numbers of GFP-expressing allo-BM-MSCs, syngeneic BM-MSCs or allo-fibroblasts were implanted into excisional wounds in GFP-negative mice. Quantification of GFP-expressing cells in wounds at 7, 14 and 28 days indicated similar amounts of allogeneic or syngeneic BM-MSCs but significantly reduced amounts of allo-fibroblasts. With healing progression, decreasing amounts of allogeneic and syngeneic BM-MSCs were found in the wound; however, the reduction was more evident (2 fold) in allo-fibroblasts. Similar effects in enhancing wound closure were found in allogeneic and syngeneic BM-MSCs but not in allo-fibroblasts. Histological analysis showed that allo-fibroblasts were largely confined to the injection sites while allo-BM-MSCs had migrated into the entire wound. Quantification of inflammatory cells in wounds showed that allo-fibroblast- but not allo-BM-MSC-treated wounds had significantly increased CD45+ leukocytes, CD3+ lymphocytes and CD8+ T cells. Our study suggests that allogeneic BM-MSCs exhibit ignorable immunogenicity and are equally efficient as syngeneic BM-MSCs in engraftment and in enhancing wound healing

Epigenetic Dysregulation in Mesenchymal Stem Cell Aging and Spontaneous Differentiation

BACKGROUND: Mesenchymal stem cells (MSCs) hold great promise for the treatment of difficult diseases. As MSCs represent a rare cell population, ex vivo expansion of MSCs is indispensable to obtain sufficient amounts of cells for therapies and tissue engineering. However, spontaneous differentiation and aging of MSCs occur during expansion and the molecular mechanisms involved have been poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: Human MSCs in early and late passages were examined for their expression of genes involved in osteogenesis to determine their spontaneous differentiation towards osteoblasts in vitro, and of genes involved in self-renewal and proliferation for multipotent differentiation potential. In parallel, promoter DNA methylation and hostone H3 acetylation levels were determined. We found that MSCs underwent aging and spontaneous osteogenic differentiation upon regular culture expansion, with progressive downregulation of TERT and upregulation of osteogenic genes such as Runx2 and ALP. Meanwhile, the expression of genes associated with stem cell self-renewal such as Oct4 and Sox2 declined markedly. Notably, the altered expression of these genes were closely associated with epigenetic dysregulation of histone H3 acetylation in K9 and K14, but not with methylation of CpG islands in the promoter regions of most of these genes. bFGF promoted MSC proliferation and suppressed its spontaneous osteogenic differentiation, with corresponding changes in histone H3 acetylation in TERT, Oct4, Sox2, Runx2 and ALP genes. CONCLUSIONS/SIGNIFICANCE: Our results indicate that histone H3 acetylation, which can be modulated by extrinsic signals, plays a key role in regulating MSC aging and differentiation

Pan-cancer identified ARPC1B as a promising target for tumor immunotherapy and prognostic biomarker, particularly in READ

ARPC1B encodes the protein known as actin-related protein 2/3 complex subunit 1 B (ARPC1B), which controls actin polymerization in the human body. Although ARPC1B has been linked to several human malignancies, its function in these cancers remains unclear. TCGA, GTEx, CCLE, Xena, CellMiner, TISIDB, and molecular signature databases were used to analyze ARPC1B expression in cancers. Visualization of data was primarily achieved using R language, version 4.0. Nineteen tumors exhibited high levels of ARPC1B expression, which were associated with different tumor stages and significantly affected the prognosis of various cancers. The level of ARPC1B expression substantially connected the narrative of ARPC1B expression with several TMB cancers and showed significant changes in MSI. Additionally, tolerance to numerous anticancer medications has been linked to high ARPC1B gene expression. Using Gene Set Variation Analysis/Gene Set Enrichment Analysisanalysis and concentrating on Rectum adenocarcinoma (READ), we thoroughly examined the molecular processes of the ARPC1B gene in pan-cancer. Using WGCNA, we examined the co-expression network of READ and ARPC1B. Meanwhile, ten specimens were selected for immunohistochemical examination, which showed high expression of ARPC1B in READ. Human pan-cancer samples show higher ARPC1B expression than healthy tissues. In many malignancies, particularly READ, ARPC1B overexpression is associated with immune cell infiltration and a poor prognosis. These results imply that the molecular biomarker ARPC1B may be used to assess the prognosis and immune infiltration of patients with READ

Experimental scheme.

<p>Experimental scheme.</p

Engraftment of BM-MSCs into the wounded skin.

<p>(A) Allo-fibroblasts or allo-MSCs in wounds. Representative fluorescence microscopic images of day 7 wound sections showing that the injected allogeneic GFP⁺fibroblasts (allo-FB) were confined to the injection site and surrounded by a layer of inflammatory and fibroblast-like cells (arrow heads, left panel). Weak GFP signals were detected in some of allo-fibroblasts. After immunostaining for GFP, topically applied allo-fibroblasts (green) were shown to be poorly incorporated into the tissue (middle and right panels of upper row) and in many of them nuclei were not shown (arrow heads, middle panel of upper row), indicating cell death, while similarly applied allo-MSCs (green) were closely integrated into the wound (lower row, representative images from three mice). Wound beds are indicated by arrows. Nuclei were stained blue with Hoechst. scale bar, 50 µm. (B) Wounds treated with allogeneic or syngeneic BM-MSCs or vehicle medium (sham) in Balb/C or C57BL/6 mice at 1 or 2 weeks were enzymatically dissociated as discribed in “<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0007119#s2" target="_blank">Materials and Methods</a>” and single-cell suspensions were analyzed by flow cytometry to detect percentages of GFP-positive cells. One representative result is shown. Cells from sham wounds were used for negative controls and gate setting. (C) Cell engraftment. Taking the initially implanted one million cells per wound as 100%, proportions of engrafted BM-MSCs or fibroblasts at different times after transplantation are shown. *<i>P</i><0.001 (allo-fibroblast vs MSC, n = 6 or 7).</p

Lithium niobate thin film electro-optic modulator

The linear electro-optic effect offers a valuable means to control light properties via an external electric field. Lithium niobate (LN), with its high electro-optic coefficients and broad optical transparency ranges, stands out as a prominent material for efficient electro-optic modulators. The recent advent of lithium niobate-on-insulator (LNOI) wafers has sparked renewed interest in LN for compact photonic devices. In this study, we present an electro-optic modulator utilizing a thin LN film sandwiched between top and bottom gold (Au) film electrodes, forming a Fabry–Pérot (F–P) resonator. This resonator exhibits spectral resonance shifts under an applied electric field, enabling efficient modulation of reflected light strength. The modulator achieved a 2.3 % modulation amplitude under ±10 V alternating voltage. Our approach not only presents a simpler fabrication process but also offers larger modulation amplitudes compared to previously reported metasurface based LN electro-optic modulators. Our results open up new opportunities for compact electro-optic modulators with applications in beam steering devices, dynamic holograms, and spatial light modulators, and more

Gene expression, histone acetylation and DNA methylation in early and late passage MSCs.

<p>(A) Real-Time PCR analysis of the expression of Nanog, REX1 and CD133 in culture passage (P) 1, passage 6 MSCs cultured in growth medium or passage 6 MSCs growth medium supplemented with bFGF (P6-bFGF). bFGF treatment started from passage 1 cells. (B) TERT histone H3 acetylation (** <i>P</i><0.01 versus P1 and P6 in bFGF-supplemented culture). (C) TERT gene expression (Real-Time PCR analysis) and, (D) DNA methylation in CpG islands in the promoter region of TERT in passage 1 and 6 MSCs cultured in growth medium versus passage 6 MSCs cultured in growth medium supplemented with bFGF (P6-bFGF).</p

Fluorescence-activated cell sorting (FACS) analysis of MSCs.

<p>Passage 3 MSCs were analyzed by FACS after staining with FITC- or PE-conjugated control isotype IgG (gray peaks) or antibodies against indicated cell surface proteins (filled red or green peaks).</p

Osteogenic gene expression, histone acetylation and DNA methylation in early and late passage MSCs.

<p>(A) Runx2 and (D) ALP histone H3 acetylation (** <i>P</i><0.01), (B) Runx2 and (E) ALP gene expression (Real-Time PCR analysis), and (C) DNA methylation in CpG islands in the promoter region of Runx2 and (F) in the in the promoter region and exon 1 region of ALP in passage (P) 1 and 6 MSCs cultured in growth medium versus passage 6 MSCs cultured in growth medium supplemented with bFGF (P6-bFGF).</p