Apoptosis-related gene expression profiles of mouse ESCs and maGSCs: role of Fgf4 and Mnda in pluripotent cell responses to genotoxicity

TNFα prevents FGF4-mediated rescue of astrocyte dysfunction and reactivity in human ALS models

Astrocytes play a crucial role in the onset and progression of amyotrophic lateral sclerosis (ALS), a fatal disorder marked by the degeneration of motor neurons (MNs) in the central nervous system. Although astrocytes in ALS are known to be toxic to MNs, the pathological changes leading to their neurotoxic phenotype remain poorly understood. In this study, we generated human astrocytes from induced pluripotent stem cells (iPSCs) carrying the ALS-associated A4V mutation in superoxide dismutase 1 (SOD1) to examine early cellular pathways and network changes. Proteomic analysis revealed that ALS astrocytes are both dysfunctional and reactive compared to control astrocytes. We identified significant alterations in the levels of proteins linked to ALS pathology and the innate immune cGAS-STING pathway. Furthermore, we found that ALS astrocyte reactivity differs from that of control astrocytes treated with tumor necrosis factor alpha (TNFα), a key cytokine in inflammatory reactions. We then evaluated the potential of fibroblast growth factor (FGF) 2, 4, 16, and 18 to reverse ALS astrocyte phenotype. Among these, FGF4 successfully reversed ALS astrocyte dysfunction and reactivity in vitro. When delivered to the spinal cord of the SOD1G93A mouse model of ALS, FGF4 lowered astrocyte reactivity. However, this was not sufficient to protect MNs from cell death. Further analysis indicated that TNFα abrogated the reactivity reduction achieved by FGF4, suggesting that complete rescue of the ALS phenotype by FGF4 is hindered by ongoing complex neuroinflammatory processes in vivo. In summary, our data demonstrate that astrocytes generated from ALS iPSCs are inherently dysfunctional and exhibit an immune reactive phenotype. Effectively targeting astrocyte dysfunction and reactivity in vivo may help mitigate ALS and prevent MN death.

FACS-array-based cell purification yields a specific transcriptome of striatal medium spiny neurons in a murine Huntington disease model

Huntington disease (HD) is a neurodegenerative disorder caused by expanded CAG repeats in the Huntingtin gene. Results from previous studies have suggested that transcriptional dysregulation is one of the key mechanisms underlying striatal medium spiny neuron (MSN) degeneration in HD. However, some of the critical genes involved in HD etiology or pathology could be masked in a common expression profiling assay because of contamination with non-MSN cells. To gain insight into the MSN-specific gene expression changes in presymptomatic R6/2 mice, a common HD mouse model, here we used a transgenic fluorescent protein marker of MSNs for purification via FACS before profiling gene expression with gene microarrays and compared the results of this "FACS-array" with those obtained with homogenized striatal samples (STR-array). We identified hundreds of differentially expressed genes (DEGs) and enhanced detection of MSN-specific DEGs by comparing the results of the FACS-array with those of the STR-array. The gene sets obtained included genes ubiquitously expressed in both MSNs and non-MSN cells of the brain and associated with transcriptional regulation and DNA damage responses. We proposed that the comparative gene expression approach using the FACS-array may be useful for uncovering the gene cascades affected in MSNs during HD pathogenesis.

Bioinformatics Analysis of Differentially Expressed Genes, Methylated Genes, and miRNAs in Unexplained Recurrent Spontaneous Abortion

Approximately half of the unexplained recurrent spontaneous abortions remain unexplained (URSAs). We aimed to provide novel insights into the biological characteristics and related pathways of differentially expressed genes (DE-genes), DE-methylated genes, and DE-miRNAs in URSA, and construct a molecular miRNAs-mRNAs network. Four data sets (GSE22490, GSE121950, GSE73025, and GSE43256) were gained from GEO data sets. We identified the DE-genes, DE-methylated genes, and DE-miRNAs using the LIMMA package in R software. Function and enrichment analyses were conducted using DAVID. A protein-protein network was performed by STRING. We predicted the target genes of DE-miRNA using DIANA-microT-CDS. Then, we constructed miRNAs-mRNAs network. There were 137 genes that overlapped in two expression profile data sets (GSE121950 and GSE22490). We found 10 overlapping DE-methylated genes and DE-genes with opposite expression alteration trends. All those 10 genes were hypermethylated lowly expressed genes. Pathway analysis illustrated that DE-genes were enriched in osteoclast differentiation, leishmaniasis, NF-kappa B signaling pathway, Toll-like receptor signaling pathway, and tuberculosis. Based on protein-protein interaction analysis, TLR8, TLR2, CD86, TLR4, IL10, CD163, FCGR1A, CXCL8, FCGR3A, HCK, PLEK, and MNDA were identified as hub genes for DE-genes. We screened out 47 DE-miRNAs and 42 overlapping DE-genes between predicted target genes of DE-miRNAs and the 137 DE-genes. We then constructed miRNAs-mRNAs network. This study identified several genes and miRNAs involved in the development and progression of URSA, including FCGR1A, FCGR3A, CXCL8, HCK, PLEK, IL10, hsa-miR-498, and hsa-miR-4530. Although further in vivo and in vitro validations are required, our results may provide a theoretical basis for future studies.

The Protective Effect of Indole-3-Acetic Acid (IAA) on H2O2-Damaged Human Dental Pulp Stem Cells Is Mediated by the AKT Pathway and Involves Increased Expression of the Transcription Factor Nuclear Factor-Erythroid 2-Related Factor 2 (Nrf2) and Its Downstream Target Heme Oxygenase 1 (HO-1)

Indole-3-acetic acid (IAA) is the most common plant hormone of the auxin class and is known to have many effects including cell proliferation enhancement and antioxidant property. However, no study has revealed its defensive effects against oxidative toxicity in human dental pulp stem cells (hDPSCs). In this study, we investigated the effects of IAA on hydrogen peroxide- (H₂O₂-) induced oxidative toxicity in hDPSCs. H₂O₂-induced cytotoxicity was attenuated after IAA treatment. Cell cycle analysis using FACS showed that the damaged cell cycle and increased number of apoptotic cells by H₂O₂ treatment were recovered after the treatment of IAA. The H₂O₂-mediated increased expression of the proapoptotic genes, BAX and p53, was attenuated by IAA treatment, while IAA treatment increased antiapoptotic genes, BCL-2 and ATF5 expression. The increases of cleaved caspase-3 and ROS by H₂O₂ were also decreased after treatment of IAA. To further investigate the mechanism of IAA, Nrf2-related antioxidant pathway was examined and the results showed that the level of Nrf2 and HO-1 expressions, stimulated by H₂O_2, decreased after treatment of IAA. Moreover, IAA treatment protected hDPSCs against H₂O₂-induced oxidative stress via increased expression of Nrf2 and HO-1, mediated by the AKT pathway.