Histochemistry and Cell Biology最新文献

Gestational diabetes mellitus (GDM) significantly disrupts placental structure and function, leading to complications such as intrauterine growth restriction (IUGR) and preeclampsia. This study aimed to investigate the effects of GDM on placental histology, angiogenesis, and oxidative stress, as well as evaluate metformin's protective role in mitigating these changes. A total of 60 pregnant Sprague-Dawley rats were divided into four groups: control, metformin-treated, GDM, and GDM with metformin. GDM was induced using streptozotocin (STZ) at 40 mg/kg, and metformin was administered at 200 mg/kg from gestational day (GD) 4 to GD17. Blood glucose and insulin levels were assessed, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) was calculated. Placentae were weighed and subjected to histological, immunohistochemical, and molecular analyses, focusing on key angiogenesis markers (VEGF, VEGFR, CD31, KLF2) and oxidative stress indicators (MDA, eNOS). GDM increased placental weight, angiogenesis (elevated VEGF, VEGFR, CD31), and oxidative stress (elevated MDA, eNOS). Histopathological changes included villous edema, membrane rupture, and hemosiderin deposition. Metformin treatment reduced placental weight; normalized VEGF, KLF2, and PlGF expression; and improved placental architecture. Additionally, oxidative stress was significantly reduced in metformin-treated GDM rats. In conclusion, GDM induces placental abnormalities, promoting excessive angiogenesis and oxidative stress, potentially leading to IUGR and other complications. Metformin showed protective effects by reducing placental overgrowth and restoring vascular and oxidative balance. These findings suggest that metformin may play a therapeutic role in improving placental health in GDM pregnancies, warranting further investigation into its long-term effects on fetal development and maternal health.

Cartilage diseases and injuries are considered difficult to treat owing to the low regenerative capacity of this tissue. Using stem cells (SCs) is one of the potential methods of treating cartilage defects and creating functional cartilage models for transplants. Their ability to proliferate and to generate functional chondrocytes, a natural tissue environment, and extracellular cartilage matrix, makes SCs a new opportunity for patients with articular injuries or incurable diseases, such as osteoarthritis (OA). The review summarizes the most important scientific reports on biology and mechanisms of SC-derived chondrogenesis and sources of SCs for chondrogenic purposes. Additionally, it focuses on the genetic mechanisms, microRNA (miRNA) regulation, and epigenetic processes steering the chondrogenic differentiation of SCs. It also describes the attempts to create functional cartilage with tissue engineering using growth factors and scaffolds. Finally, it presents the challenges that researchers will have to face in the future to effectuate SC differentiation methods into clinical practice for treating cartilage diseases.

Bone marrow mesenchymal stromal cells (BM-MSCs) are integral components of the bone marrow microenvironment, playing a crucial role in supporting hematopoiesis. Recent studies have investigated the potential involvement of BM-MSCs in the pathophysiology of acute lymphoblastic leukemia (ALL). However, the exact contribution of BM-MSCs to leukemia progression remains unclear because of conflicting findings and limited characterization. In this study, we compared BM-MSCs derived from pediatric ALL patients with those from matched healthy donors (HDs). Our results indicate that while both ALL-MSCs and HD-MSCs meet the criteria established by the International Society for Cellular Therapy, they exhibit significant differences in proliferation and differentiation capacity. ALL-MSCs displayed markedly lower proliferation rates and reduced osteogenic/adipogenic differentiation potential compared to HD-MSCs. Furthermore, co-culture experiments revealed that MSCs enhance the survival of leukemic blasts through both soluble factors and direct cell-cell interactions, underscoring their anti-apoptotic properties. Importantly, our findings demonstrate that interactions with leukemic cells activate the Wnt/β-catenin signaling pathway in MSCs, suggesting a potential target for therapeutic intervention. Overall, this study enhances our understanding of the role of BM-MSCs in leukemia and highlights β-catenin as a promising target for future therapies.

Skin-derived stem cells (SDSCs) are a subtype of adult stem cells (ASCs) that are widely harvested and exempt from ethical restrictions in clinical applications. These cells possess capabilities for self-renewal, proliferation, and multi-lineage differentiation. Compared to model animals like rats and mice, pigs exhibit greater physiological similarity to humans. Porcine skin has very similar histological and physiological characteristics to human skin. Therefore, porcine skin is becoming increasingly significant as an in vitro model for research. In this study, porcine skin-derived stem cells (pSDSCs) were isolated and cultured in vitro for experiments. The expression of stemness-related gene SOX9 was detected. RNA sequencing (RNA-seq) results found that the mammalian target of rapamycin (mTOR) signaling pathway was significantly enriched in SOX9⁺ pSDSCs. To investigate the role of the mTOR signaling pathway, we added rapamycin (RAPA), an inhibitor of the mTOR complex 1 (mTORC1), and found that the proliferation rate of SOX9⁺ pSDSCs decreased significantly during culture. In addition, western blotting (WB) results demonstrated that mTORC1 promoted proliferation by phosphorylating S6 kinase (S6K) and then activating cyclin D1(CCND1) in SOX9⁺ pSDSCs. These findings provide insights into the mechanisms of adult stem cell proliferation.

The tumor microenvironment is an altered milieu that imposes multiple selective pressures leading to the survival and dissemination of aggressive and fit tumor cell subpopulations. How pre-tumoral and tumoral cells respond to changes in their microenvironment will determine the subsequent evolution of the tumor. In this study, we have subjected pre-tumoral and tumoral cells to coverslip-induced hypoxia, which recapitulates the intracellular hypoxia and extracellular acidification characteristic of the early tumor microenvironment, and we have used a combination of quantitative phase microscopy and epifluorescence to analyze diverse cellular responses to this altered environment. In normoxia, tumor cells showed differences in nuclear organization, as evidenced by decreased numbers of HP1 foci, and in hypoxia major changes in nuclear architecture were observed, with tumor cells significantly increasing the number of high dry mass density foci in the nucleus compared to pre-tumoral and non-tumoral cells. Conversely, compared to pre-tumoral and normal cells, mitochondrial ATP levels decayed markedly in tumor cells in hypoxia, whereas the activation of executioner caspases increased only in tumor cells in this condition. Therefore, in terms of cellular organization, metabolic changes and activation of cell death processes, tumor cells showed more dramatic responses to an altered microenvironment than their pre-tumoral and normal counterparts, responses which in turn could play fundamental roles in shaping future tumor development.

A20, an ubiquitin-editing enzyme, plays a pivotal role in regulating cell signaling and immune responses. Dysregulated A20 expression has been associated with various pathological conditions, including inflammatory diseases and malignancies, where its expression levels often correlate with differing prognoses in solid tumors. This study aimed to explore the expression and cellular localization of A20 in both nonpathological and diseased human gastric tissues to gain deeper insights into its involvement in gastric pathologies. We analyzed paraffin-embedded gastric tissue samples from 326 patients. A20 expression was assessed using immunohistochemistry (IHC) with results categorized according to the Remmele and Stegner immunoreactive score (IRS). The study compared A20 expression across a spectrum of gastric pathologies, including Helicobacter pylori (HP) gastritis, autoimmune gastritis (A-gastritis), reactive gastropathy (C-gastritis), Ex-HP-gastritis, adenomas, and adenocarcinomas, with nonpathological gastric mucosa serving as a baseline. Our findings demonstrate a significant increase in A20 expression in HP-gastritis (p = 0.019), A-gastritis (p = 0.001), adenomas (p < 0.001), and adenocarcinomas (p < 0.001). Conversely, no significant differences in A20 expression were observed in C-gastritis or Ex-HP-gastritis cases.

METTL3, an m6A methyltransferase, is integral to the regulation of messenger RNA (mRNA) biogenesis, degradation, and translation through the N6-methyladenosine (m6A) modification. Alterations in m6A homeostasis have been implicated in the development, progression, invasion, and metastasis of certain cancers. The present research aims to examine the consequences of METTL3 knockdown using short hairpin RNA (shRNA) on the proliferation and invasive capabilities of human colorectal and melanoma cancer cell lines. A specific shRNA against METTL3 mRNA was designed and inserted into an expression vector. Highly invasive colorectal cancer cell line SW480 and melanoma cell line A375 were cultured and transfected by METTL3-shRNA and scramble-control vectors and kept under culture condition for 2 weeks. The cells were harvested for analysis of gene expression by quantitative polymerase chain reaction (qPCR), invasion assay using three-dimensional (3D) spheroid assay and cell cycle and apoptosis analyses. In the METTL3-shRNA transfected cells, the expression of METTL3, VIM, SNAI1, SNAI2, ZEB1, CDH1, and TGFB1 genes were downregulated significantly compared with the scramble-control transfected cells. Expression of b-catenin, N-cadherin, vimentin, ZEB1, pro- and active MMP2, OCT4A, SOX2, and MYC proteins were also downregulated following METTL3 knockdown. Transfection by METTL3-shRNA reduced proliferation rate of the cells and increased the apoptotic rate significantly. Both migration and invasion rate of the cancer cells transfected with METTL3-shRNA were significantly decreased. These findings highlight the pro-oncogenic function of METTL3 in colorectal and melanoma cancer cells, indicating that inhibiting METTL3 could be a promising approach for tumor suppression across multiple cancer types; nonetheless, further investigation is essential to confirm these observations.

Oxidative stress-induced DNA damage is an important mechanism that leads to the death of neuronal cells after ischemic stroke. Our previous study found that Ku70 was highly expressed in ischemic brain tissue of rats after cerebral ischemia-reperfusion injury. However, the role of Ku70 in glucose-oxygen deprivation/reperfusion (OGD/R) in astrocytes has not been reported. Therefore, we investigated the effect and mechanism of Ku70 on OGD/R-induced astrocyte injury in rats. Rat astrocytes were cultured in vitro to establish the OGD/R-induced injury model and transfected with small interfering RNA (siRNA) to disturb Ku70 expression. Real-time quantitative polymerase chain reaction (RT-qPCR), western blotting, and immunofluorescence were performed to assay the expression of mRNA and proteins. Cell viability, apoptosis, and ROS accumulation were determined by CCK-8 assay, flow cytometry, and fluorescence microscopy, respectively. Our results showed Ku70 can be expressed in both the nucleus and cytoplasm of astrocytes, although mainly in the nucleus. Ku70 expression showed a trend of first increasing and then decreasing after OGD/R, reaching its highest change at 24 h of reoxygenation. OGD/R induced ROS production and DNA damage in rat astrocytes, and Ku70 silencing further increased ROS production and DNA lesions, which aggravated astrocyte injury and apoptosis. Furthermore, the expression of p53, Bax, and caspase 3 proteins significantly increased after OGD/R in astrocytes, and downregulation of Ku70 further enhanced expression of the above proteins. These results indicate that Ku70 silencing promotes OGD/R-induced astrocyte apoptosis, which may be associated with p53 apoptotic pathway activation. Our study suggests that Ku70 may be a novel target for cerebral ischemia-reperfusion injury therapy.

Hematopoietic stem cells (HSCs) reside in a milieu that supports their functions, differentiation, and survival. This niche consists of several types of cells, including mesenchymal stem/stromal cells, endothelial cells, osteoblasts, megakaryocytes, macrophages, adipocytes, lymphoid cells, and nerve fibers. The interactions between these cells and HSCs have a role in HSC fate. Several studies have focused on identification of the biological and cellular mechanisms contributing to the establishment of this niche. However, the exact mechanisms of the interaction between HSCs and the bone marrow niche have not been elucidated yet. Unraveling these mechanisms would help in the design of effective methods for maintenance and multiplication of HSCs in clinical settings, in addition to establishment of novel therapies for hematopoietic diseases. The current review summarizes the effects of the niche cells on HSC function and underlying mechanisms of interplay between HSCs and their niche.