Di-2-(ethylhexyl)phthalate (DEHP) is a phthalate derivative used extensively in a wide range of materials, such as medical devices, toys, cosmetics, and personal care products. Many mechanisms, including epigenetics, may be involved in the effects of phthalates on brain development. In this study, Sprague-Dawley male rats were obtained 21-23 days after their birth (post-weaning) and were exposed to DEHP during the prepubertal period with low-dose DEHP (DEHP-L, 30 mg/kg/day) and high-dose DEHP (DEHP-H, 60 mg/kg/day, 37 days) until the end of adolescence (PND 60). The rats in the study groups were sacrificed during adulthood, and histopathological changes, epigenetic changes, and oxidative stress parameters were evaluated in brain tissues. Histopathological findings indicating the presence of deterioration in brain tissue morphology were obtained, more prominently in the DEHP-H group. Examining the hippocampus under the light microscope, pyramidal neuron loss was detected only in CA1 of the DEHP-L group, while in DEHP-H rats, pyramidal neuron losses were detected in the CA1, CA2, and CA3 regions. No significant change was observed in brain lipid peroxidation levels with DEHP compared to control. Significant increases in total glutathione (GSH) in both dose groups were considered to be an adaptive response to DEHP-induced oxidative stress. The decrease in DNA methylation in the brain, although not statistically significant, and the increase in histone modification showed that exposure to DEHP may cause epigenetic changes in the brain and these epigenetic changes may also take place as one of the mechanisms underlying the damage observed in the brain. The results suggest that DEHP exposure during early development may have a significant effect on brain development.
The Hippo pathway, with its core components and the downstream transcriptional coactivators, controls the self-renewable capacity and stemness features of stem cells and serves as a stress response pathway by regulating proliferation, differentiation and apoptosis. The Hippo pathway interaction with other signaling pathways plays an important role in response to various stress stimuli arising from energy metabolism, hypoxia, reactive oxygen species, and mechanical forces. Depending on the energy levels, the Hippo pathway is regulated by AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR), which in turn determines stem cell proliferation (cell survival and growth) and differentiation. Oxidative stress-driven by ROS production also affects the Hippo pathway with transcriptional changes through MST/YAP/FoxO pathway and leads to the activation of pro-apoptotic genes and eventually cell death. HIF1alpha/YAP signaling is critical for the long-term maintenance of mesenchymal stem cells (MSCs) under hypoxia. In this review, we present an overview of stem cell response to stress, including mechanical, hypoxia, metabolic and oxidative stress through the modulation of the Hippo pathway. The biological effects such as autophagy, apoptosis and senescence were discussed in the context of the Hippo pathway in stem cells.
Alzheimer's disease (AD) is a neurodegenerative disorder that causes memory loss and dementia and is characterized by a decline in cognitive functions. Brain infections, especially induced by herpes simplex virus type-1 (HSV-1), are suggested to play a key role in the pathogenesis of AD. Within the scope of this study, two different AD models (Tau model and amyloid beta [Aβ]) were created in the SH-SY5Y cell line, and HSV glycoprotein B (gB) was applied to the cell line and on the generated AD models. Study groups (n = 3) were designed as (1) control, (2) HSV-gB group, (3) retinoic acid (RA) and brain derived neurotrophic factor (BDNF) induced Alzheimer's model (AD), (4) RA and BDNF induced Alzheimer's model + HSV-gB (ADH), (5) Aβ 1-42 peptide-induced Alzheimer's model (Aβ), and (6) Aβ 1-42 peptide-induced Alzheimer's model + HSV-gB (AβH). Levels of complement proteins and cytokines were determined comparatively. In addition, specific markers of AD (hyperphosphorylated Tau proteins, Aβ 1-40 peptide and amyloid precursor protein) were measured in all groups. HSV-gB administration was found to increase Aβ and hyperphosphorylated Tau levels, similar to AD models. In addition, our data confirmed that the immune system and chronic inflammation might have a crucial role in AD development and that HSV-1 infection might also be an underlying factor of AD.
Abstract The expression of glutathione S-transferase P1 (GSTP1) enzyme increases in cancer cells, leading to anticancer drug resistance. The antioxidant chlorophyllin has an inhibitory effect on GSTP1. In this study, we investigated the effects of chlorophyllin and its combined administration with the chemotherapeutic agent docetaxel on metastatic processes. For this purpose, both the 4T1 triple-negative breast cancer cell line and metastatic animal model were used. The MTT, flow cytometry, and wound healing assays were used to investigate cell viability, cell cycle, and cell migration, respectively. Western blot analysis was used to evaluate the expression of matrix metalloproteinase 9 (MMP-9). Total gelatinase activity, GST activity, and glutathione levels in cell and liver tissue lysates measured by colorimetric methods. Micrometastases were evaluated in liver tissue sections histochemically. As a result, the coadministration of chlorophyllin and docetaxel inhibited cell migration in vitro. The single administration of chlorophyllin reduced the MMP-9 expression in vivo, and this effect was higher when it was coadministered with docetaxel. In coadministration, there was also a significant decrease in the total gelatinase activity in vivo . Finally, we found that only combined treatment reduced the micrometastatic lesions in the liver tissues. In conclusion, the coadministration of chlorophyllin and docetaxel may have a potential role in the control of metastatic processes by suppressing cell migration, invasion, and micrometastasis formation in triple-negative breast cancers.
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