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MESH1 is the metazoan homolog of bacterial SpoT, the main phosphatase that dephosphorylates and degrades (p)ppGpp, the alarmone involved in the bacterial stringent response. The functional role of MESH1 in human cells is unknown. To define the global transcriptional response to MESH1 knockdown, we employed microarrays to perform transcriptome analysis of H1975 when the MESH1 was knocked down using three independent siRNAs targeting MESH1. The changes of each gene were derived by zero-transformation, followed by filtering to derive the genes affected by MESH1 knockdown. These datasets showed the transcriptional features of the mammalian stringent response and identified a prominent TAZ repression. Thus, we performed a second experiment to determine the contribution of TAZ repression to the transcriptional response of MESH1 knockdown by comparing the effects of MESH1-knockdown gene signatures in H1975 cells transduced with control or constitutive active TAZ (TAZS89A). The transcriptional response of these two cells to MESH1 was derived by zero transformation, followed by the effects of TAZ restoration to define the contribution of TAZ repression to the transcriptome features of human stringent response. The transcriptome data will be useful for the mechanistic understanding of the functional role of MESH1 in human cancer cells.

Simple Summary: The physiological status of a dairy cow's udder is significantly impacted by heat stress (HS). Therefore, improving the physiological function of dairy cow udders under HS conditions is important to improve animal welfare and dairy production efficiency. In the present study, we found that HS inhibited the proliferation of bovine mammary epithelial cells (BMECs) and significantly downregulated the expression of endogenous miR-196a. Furthermore, overexpression of miR-196a could alleviate the inhibitory effect of HS on BMEC proliferation. Additional data confirmed that miR-196a promoted BMEC proliferation. Subsequently, we identified CDKN1B as a target gene of miR-196a. The effect of miR-196a on BMEC proliferation was reversed by CDKN1B. In summary, we found that miR-196a could promote BMEC proliferation by targeting CDKN1B. These findings can provide a reliable reference for alleviating the inhibition of BMEC proliferation caused by HS. Heat stress (HS) has become one of the key challenges faced by the dairy industry due to global warming. Studies have reported that miR-196a may exert a role in the organism's response to HS, enhancing cell proliferation and mitigating cellular stress. However, its specific role in bovine mammary epithelial cells (BMECs) remains to be elucidated. In this study, we aimed to investigate whether miR-196a could protect BMECs against proliferation arrest induced by HS and explore its potential underlying mechanism. In this research, we developed an HS model for BMECs and observed a significant suppression of cell proliferation as well as a significant decrease in miR-196a expression when BMECs were exposed to HS. Importantly, when miR-196a was overexpressed, it alleviated the inhibitory effect of HS on cell proliferation. We conducted RNA-seq and identified 105 differentially expressed genes (DEGs). Some of these DEGs were associated with pathways related to thermogenesis and proliferation. Through RT-qPCR, Western blotting, and dual-luciferase reporter assays, we identified CDKN1B as a target gene of miR-196a. In summary, our findings highlight that miR-196a may promote BMEC proliferation by inhibiting CDKN1B and suggest that the miR-196a/CDKN1B axis may be a potential pathway by which miR-196a alleviates heat-stress-induced proliferation arrest in BMECs. [ABSTRACT FROM AUTHOR]

MESH1 is the metazoan homolog of bacterial SpoT, the main phosphatase that dephosphorylates and degrades (p)ppGpp, the alarmone involved in the bacterial stringent response. The functional role of MESH1 in human cells is unknown. To define the global transcriptional response to MESH1 knockdown, we employed microarrays to perform transcriptome analysis of H1975 when the MESH1 was knocked down using three independent siRNAs targeting MESH1. The changes of each gene were derived by zero-transformation, followed by filtering to derive the genes affected by MESH1 knockdown. These datasets showed the transcriptional features of the mammalian stringent response and identified a prominent TAZ repression. Thus, we performed a second experiment to determine the contribution of TAZ repression to the transcriptional response of MESH1 knockdown by comparing the effects of MESH1-knockdown gene signatures in H1975 cells transduced with control or constitutive active TAZ (TAZS89A). The transcriptional response of these two cells to MESH1 was derived by zero transformation, followed by the effects of TAZ restoration to define the contribution of TAZ repression to the transcriptome features of human stringent response. The transcriptome data will be useful for the mechanistic understanding of the functional role of MESH1 in human cancer cells.

Telomerase activity has been regarded as a critical step in cellular immortalization and carcinogenesis and because of this, regulation of telomerase represents an attractive target for anti-tumor specific therapeutics. Recently, one avenue of cancer research focuses on antisense strategy to target the oncogenes or cancer driver genes, in a sequence specific fashion to down-regulate the expression of the target gene. The protein catalytic subunit, human telomerase reverse transcriptase (hTERT) and the template RNA component (hTERC) are essential for telomerase function, thus theoretically, inhibition of telomerase activity can be achieved by interfering with either the gene expression of hTERT or the hTERC of the telomerase enzymatic complex. The present study showed that phosphorothioate antisense oligonucleotide (sASO)-nuclear localization signal (NLS) peptide conjugates targeting hTERC could inhibit telomerase activity very efficiently at 5 μM concentration but less efficiently at 1 μM concentration. On the other hand, siRNA targeting hTERT mRNA could strongly suppress hTERT expression at 200 nM concentration. It was also revealed that siRNA targeting hTERT could induce telomere attrition and then irreversible arrest of proliferation of cancer cells. [ABSTRACT FROM AUTHOR]

Recognition of gene promoters by RNA polymerase II is mediated by general transcription factor IID (TFIID), which has been thought to be a static complex and to play a passive role in the regulation of gene expression under the instruction of gene-specific transcription factors. Here we show that transforming growth factor β (TGFβ) induced degradation of the TFIID subunit TAF7 in cultured mouse mammary epithelial cells and that this effect was required for proliferative arrest in response to TGFβ stimulation. TGFβ stimulated transcription of the gene for the ubiquitin ligase TRIM26, which was shown to ubiquitylate TAF7 and thereby to target it for proteasomal degradation. Sustained exposure of cells to TGFβ resulted in recovery from proliferative arrest in association with amplification of the Myc proto-oncogene, with MYC inhibiting TRIM26 induction by TGFβ. Our data thus show that TFIID is not simply a general mediator of transcription but contributes to the regulation of transcription in response to cell stimulation, playing a key role in the cytostatic function of TGF-β. [ABSTRACT FROM AUTHOR]

The article presents a study which examines neural precursor cells derived from subventricular zone of rats that underwent oligodendroglial and astroglial differentiation after limited propagation. It states that the differentiation was mainly induced by autocrine or paracrine bone morphogenetic platelet and protein derived growth factor signals. Results indicate that adult rat neural precursor cells could be cultured in vitro as tripotent stem cell lines.

The activating protein-1 (AP-1) transcription factor transduces growth signals through signal transduction pathways to the nucleus, leading to the expression of genes involved in growth and malignant transformation in many cell types. We have previously shown that overexpression of a dominant negative form of the cJun proto-oncogene, a cJun dominant negative mutant (Tam67), blocks AP-1 transcriptional activity, induces a G1 cell cycle block and inhibits breast cancer cell growth in vitro and in vivo. We found that AP-1 blockade by Tam67 in MCF-7 breast cancer cells downregulates cyclin D1 transcriptional activity by at least two mechanisms: by suppressing transcription at the known AP-1 binding site (−934/−928) and by suppressing growth factor-induced expression through suppressing E2F activation at the E2F-responsive site (−726/−719). AP-1 blockade also led to reduced expression of E2F1 and E2F2, but not E2F4, at the mRNA and protein levels. Chromatin immunoprecipitation and supershift assays demonstrated that AP-1 blockade caused decreased binding of E2F1 protein to the E2F site in the cyclin D1 promoter. We also found that Tam67 suppressed the expression of the E2F1 dimerizing partner, DP1 and E2F-upregulated cell cycle genes (cyclins E, A, B and D3) and enhanced the expression of E2F-downregulated cell cycle genes (cyclins G2 and I). Reduced expression of other E2F-regulated genes was also seen with AP-1 blockade and E2F suppression. Thus, the AP-1 factor regulates the expression of cyclin D and E2F (the latter in turn regulates E2F-downstream genes), leading to cell cycle progression and breast cancer cell proliferation.Oncogene (2008) 27, 366–377; doi:10.1038/sj.onc.1210643; published online 16 July 2007 [ABSTRACT FROM AUTHOR]

The CCAAT/enhancer-binding protein (C/EBP) family of transcription factors plays an important role in controlling cell proliferation and differentiation. C/EBPα is a particularly potent regulator of cell-cycle exit and is induced in terminally differentiating adipocytes and myeloid cells, where it also activates differentiation-specific genes. The growth-inhibiting activity of C/EBPα suppresses tumorigenesis in myeloid cells and possibly other tissues. In addition, recent work has identified C/EBPα as a component of the p53-regulated growth arrest response elicited by DNA damage in epidermal keratinocytes. Several studies have explored the mechanism by which C/EBPα blocks cell-cycle progression at the G1-S boundary, and several models have been proposed but no universally accepted mechanism has emerged. Controversial issues include whether C/EBPα acts through an ‘off-DNA’ mechanism to inhibit cyclin-dependent kinases, and whether and how it functions with the RB-E2F system to repress transcription of S-phase genes. Other C/EBP-family members have also been implicated in positive and negative control of cell proliferation, and the mechanisms underlying their growth-regulatory activities are beginning to be elucidated. [ABSTRACT FROM AUTHOR]

Abstract: Three diterpene compounds isolated from the anti-cancer herbal medicine kansui, namely, kansuinin B, 20-OD-ingenol Z, and 20-OD-ingenol E, specifically inhibited the proliferation of isolated embryonic cells from Xenopus embryos. We conducted a cytologic study to determine the mechanism underlying the arrest of the cellular proliferation by these compounds. While kansuinin B and 20-OD-ingenol Z treatment decreased the cell numbers in the S phase and the M phase substages of the cell cycle, 20-OD-ingenol E inhibited mitosis. [Copyright &y& Elsevier]

β-Glucans are considered candidates for the medication in different human pathologies. In this work, we have purified β-glucan from a selected barley line and tested their effects in primary human dermal fibroblasts. Unexpectedly, we have observed that this compound promoted a short-transitory proliferation arrest at 24 h after its addition on the medium. We have determined that this transitory arrest was dependent on the cell-cycle regulator protein Retinoblastoma. Moreover, dermal fibroblasts increase their migration capacities at 24 h after barley β-glucan addition. Also, we have described that barley β-glucan strongly reduced the ability of fibroblasts to attach and to spread on cell plates. Our data indicates that barley β-glucan signal induces an early response in HDF cells favoring migration versus proliferation. This feature is consistent with our observation that the topical addition of our barley β-glucan in vivo accelerates the wound closure in mouse skin., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)