Alireza Tavakolpournegari

Environmental degradation and accumulation of plastics results in micro- and nanoplastics (MNPLs) that are small enough to cross biological barriers, including the blood–brain barrier. Microglia, resident immune cells of brain, are critical regulators of neuroimmune homeostasis and represent a cellular target of nanoplastic exposure. In this study, we assessed the neurotoxic effects of two sizes of polystyrene nanoplastics (PS-NPs; 100 nm and 500 nm) using integrated in vivo and in vitro exposure and washout paradigms. In vivo exposure in mice (60 days; 0.15 or 1.5 mg/day) showed the accumulation of both PS-NP sizes in the cerebral cortex without histopathological damage. However, cortical microglia showed pronounced morphological remodeling, observed as increased expression of Iba1 and GFAP. Transcriptomic profiling of cortical tissue revealed a strong size-dependent response. The 100 nm PS-NP group revealed 18 DEGs (|log ₂ FC| ≥ 2, padj < 0.05), whereas the 500 nm PS-NPs showed more than 4,000 DEGs, including upregulation of immune- and microglia-associated genes (CCL5, CXCL10, LCN2, LYZ2) and downregulation of synaptic and neuronal signaling genes (GRIN2B, SYN1, STX1B, MAP1B, ITPR1/2). In vitro assessment, using BV2 microglia cells, showed internalization of PS-NPs via the endolysosomal pathway, with strong co-localization to Rab7- and LAMP2-positive compartments and prolonged intracellular retention following exposure washout. Also, microglial activation markers (Iba1, CD68) exhibited a transient, size- and concentration-dependent increase, correlated with intracellular particle burden rather than cumulative exposure. Overall, these findings demonstrate that PS-NPs accumulate in brain, driving size-dependent microglia activation and transcriptomic reprogramming, even after cessation of exposure to PS-NPs. Highlights: PS-NPs (100 nm and 500 nm) reach mouse cerebral cortex following 60-day oral exposure. PS-NPs were internalized by microglia; accumulated in endolysosomal compartments. PS-NP exposure induced transient microglial activation without sustained cytotoxicity. Microglial activation was correlated with intracellular PS-NPs burden. Transcriptomics revealed disruption of neuroimmune and microglial regulatory pathways.

Cancer remains a major global health burden driven by genetic, metabolic, and microenvironmental alterations. Although reactive oxygen species (ROS) and oxidative stress have long been implicated in cancer biology, current understanding remains fragmented and, in several areas, conceptually disputed considering how ROS and oxidative stress thresholds determine the switch between tumor-promoting signaling and cytotoxic outcomes, and whether redox-based therapies can be safely and selectively applied across different cancer types. Moreover, existing studies often examine isolated pathways or single ROS, leaving unanswered the question of how spatial and temporal ROS dynamics and oxidative stress responses shape carcinogenesis, metastasis, and therapeutic resistance. This review moves beyond descriptive summarization by critically examining unresolved mechanistic gaps, including (i) how ROS and oxidative stress interact with epigenetic and metabolic reprogramming, (ii) the context-dependent role of ROS-driven oxidative stress within the tumor microenvironment and immune evasion, and (iii) why ROS-targeting and oxidative stress-modulating therapies have shown inconsistent clinical translation despite promising preclinical data. We highlight areas of consensus as well as conflicting evidence, synthesizing recent advances across multiple cancer types to clarify where ROS and oxidative stress function as drivers, modulators, or vulnerabilities. Finally, we outline emerging research priorities, such as real-time redox profiling, subtype-specific targeting strategies, and combination approaches, to guide the development of more precise and effective ROS- and oxidative-stress-based interventions.

In the last twenty years, an increasing volume of research has characterized lipids as dynamic signaling molecules that play essential roles in various physiological and pathological processes, especially concerning chronic diseases such as cardiovascular disorders, diabetes, liver disease, neurodegeneration, cancer, obesity, diabetic and chronic kidney diseases and atherosclerosis. Dysregulation of lipid synthesis and storage, lipolysis, fatty acid oxidation, lipid signaling pathways, and organelle-specific lipid modifications, including mitochondrial phospholipid remodeling and endoplasmic reticulum stress induced by saturated fatty acids, are recognized as contributors to the initiation and progression of this pathogenesis. Concurrently with the increasing comprehension of lipid metabolism, the last decade has seen progress in the understanding of genome control, especially with non-coding RNAs (ncRNAs). MicroRNAs, long non-coding RNAs, and circular RNAs, as ncRNAs, are essential modulators of gene expression at the epigenetic, transcriptional, and post-transcriptional levels that affect a number of lipid metabolism-related processes, such as fatty acid synthesis and oxidation, cholesterol homeostasis, and lipid droplet dynamics. Therapeutically, ncRNAs hold considerable promise owing to their tissue specificity and modularity, with antisense oligonucleotides and CRISPR-based editing currently under preclinical evaluation. In this context, we review recent studies exploring the interplay between ncRNAs and the regulatory networks governing lipid metabolism, and how disruptions in these networks contribute to chronic disease. This emerging paradigm underscores the role of ncRNA–lipid metabolism interactions as central nodes in metabolic and inflammatory pathways, highlighting the need for a holistic approach to therapeutic targeting.

Cellular stressors have been demonstrated to exert a substantial influence on the functionality of organelles, thereby impacting cellular homeostasis and contributing to the development of disease pathogenesis. This review aims to examine the impact of diverse stressors, including environmental, chemical, biological, and physical factors, on critical organelles such as the cell membrane, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, and membrane-less organelles. The intricate molecular mechanisms underlying cellular stress responses, encompassing oxidative stress, protein misfolding, and metabolic reprogramming, have the capacity to elicit adaptive responses or culminate in pathological conditions. The interplay between these stressors and organelle dysfunction has been implicated in a myriad of diseases, including neurodegenerative disorders, cancer, metabolic disorders, and immune-related pathologies. A comprehensive understanding of the mechanisms by which organelles respond to stress can offer valuable insights into the development of therapeutic strategies aimed at mitigating cellular damage.

Background: One of the important molecular pathways in breast cancer is the PTEN-PI3K-AKT pathway. Any change in the activity of the PTEN gene can alter the PI3K-AKT pathway. Moreover, there are subsets of genes and pathways their expression changes by post-transcriptional regulations. For instance, gene regulation alters by non-coding RNAs such as micro-RNAs as post-transcriptional regulators that prevent the expression of the target transcript. Therefore, it is essential to assess the related alterations in micro-RNA expression patterns to find out the possible causes of conversions in related transcripts and pathways such as the PTEN-PI3K-AKT pathway in breast cancer. Methods: To determine the expression level of miR-181a and miR-30d in 30 breast tumor samples and 30 adjacent normal samples, the RNA extraction, and cDNA synthesis was performed by RiboEx (GeneAll, Korea). Finally, the Real-Time PCR method was used for quantitative analysis of the expression levels of these miRNAs. all the experimental part of the project in done at Islamic Azad University in 2017. Results: After analyzing comparisons in the expression level of miR-181a and miR-30d in tumor and normal tissues, there was a significant increase in the expression level of miR-181a in tumor samples compared with normal samples. Moreover, the expression level of miR-30d in tumor samples reported a significant decrease in comparison with normal samples (P<0.05). Conclusion: Upregulation of miR-181a may affect the transcription of the PTEN gene resulting in the cell progress to cancer. The Downregulation of miR-30d may also lead to cancer cell growth, due to a reduction in the affecting on the CREB gene transcript.