bims-raghud Biomed News
on RagGTPases in human diseases
Issue of 2025–03–16
three papers selected by
Irene Sambri, TIGEM



  1. Int J Mol Sci. 2025 Feb 23. pii: 1917. [Epub ahead of print]26(5):
      Mitochondrial dysfunction is increasingly recognized as a central contributor to the pathogenesis of cardiovascular diseases (CVDs), including heart failure, ischemic heart disease, hypertension, and cardiomyopathy. Mitochondria, known as the powerhouses of the cell, play a vital role in maintaining cardiac energy homeostasis, regulating reactive oxygen species (ROS) production and controlling cell death pathways. Dysregulated mitochondrial function results in impaired adenosine triphosphate (ATP) production, excessive ROS generation, and activation of apoptotic and necrotic pathways, collectively driving the progression of CVDs. This review provides a detailed examination of the molecular mechanisms underlying mitochondrial dysfunction in CVDs, including mutations in mitochondrial DNA (mtDNA), defects in oxidative phosphorylation (OXPHOS), and alterations in mitochondrial dynamics (fusion, fission, and mitophagy). Additionally, the role of mitochondrial dysfunction in specific cardiovascular conditions is explored, highlighting its impact on endothelial dysfunction, myocardial remodeling, and arrhythmias. Emerging therapeutic strategies targeting mitochondrial dysfunction, such as mitochondrial antioxidants, metabolic modulators, and gene therapy, are also discussed. By synthesizing recent advances in mitochondrial biology and cardiovascular research, this review aims to enhance understanding of the role of mitochondria in CVDs and identify potential therapeutic targets to improve cardiovascular outcomes.
    Keywords:  cardiovascular disease; mitochondrial dynamics; mitochondrial dysfunction; oxidative stress
    DOI:  https://doi.org/10.3390/ijms26051917
  2. Int J Mol Sci. 2025 Feb 21. pii: 1868. [Epub ahead of print]26(5):
      The phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of the rapamycin (mTOR) pathway plays a crucial role in the regulation of autophagy, a cellular mechanism vital for homeostasis through the degradation of damaged organelles and proteins. The dysregulation of this pathway is significantly associated with cancer progression, metastasis, and resistance to therapy. Targeting the PI3K/AKT/mTOR signaling pathway presents a promising strategy for cancer treatment; however, traditional therapeutics frequently encounter issues related to nonspecific distribution and systemic toxicity. Nanoparticle-based drug delivery systems represent a significant advancement in addressing these limitations. Nanoparticles enhance the bioavailability, stability, and targeted delivery of therapeutic agents, facilitating the precise modulation of autophagy in cancer cells. Functionalized nanoparticles, such as liposomes, polymeric nanoparticles, and metal-based nanocarriers, facilitate targeted drug delivery to tumor tissues, minimizing off-target effects and improving therapeutic efficacy. These systems can deliver multiple agents concurrently, enhancing the modulation of PI3K/AKT/mTOR-mediated autophagy and related oncogenic pathways. This review examines advancements in nanoparticle-mediated drug delivery that target the PI3K/AKT/mTOR pathway, emphasizing their contribution to improving precision and minimizing side effects in cancer therapy. The integration of nanotechnology with molecularly targeted therapies presents substantial potential for addressing drug resistance. Future initiatives must prioritize the optimization of these systems to enhance clinical translation and patient outcomes.
    Keywords:  PI3K/AKT/mTOR; autophagy; cancer therapy; drug delivery; nanoparticles; targeted therapy
    DOI:  https://doi.org/10.3390/ijms26051868
  3. Cell Discov. 2025 Mar 11. 11(1): 22
      PTEN-induced kinase-1 (PINK1) is a crucial player in selective clearance of damaged mitochondria via the autophagy-lysosome pathway, a process termed mitophagy. Previous studies on PINK1 mainly focused on its post-translational modifications, while the transcriptional regulation of PINK1 is much less understood. Herein, we reported a novel mechanism in control of PINK1 transcription by SMAD Family Member 3 (SMAD3), an essential component of the transforming growth factor beta (TGFβ)-SMAD signaling pathway. First, we observed that mitochondrial depolarization promotes PINK1 transcription, and SMAD3 is likely to be the nuclear transcription factor mediating PINK1 transcription. Intriguingly, SMAD3 positively transactivates PINK1 transcription independent of the canonical TGFβ signaling components, such as TGFβ-R1, SMAD2 or SMAD4. Second, we found that mitochondrial depolarization activates SMAD3 via PINK1-mediated phosphorylation of SMAD3 at serine 423/425. Therefore, PINK1 and SMAD3 constitute a positive feedforward loop in control of mitophagy. Finally, activation of PINK1 transcription by SMAD3 provides an important pro-survival signal, as depletion of SMAD3 sensitizes cells to cell death caused by mitochondrial stress. In summary, our findings identify a non-canonical function of SMAD3 as a nuclear transcriptional factor in regulation of PINK1 transcription and mitophagy and a positive feedback loop via PINK1-mediated SMAD3 phosphorylation and activation. Understanding this novel regulatory mechanism provides a deeper insight into the pathological function of PINK1 in the pathogenesis of neurodegenerative diseases such as Parkinson's disease.
    DOI:  https://doi.org/10.1038/s41421-025-00774-4