Biology subjects

Elorza, A. A.

Publications and source records attributed to Elorza, A. A..

3 recordsLinked to original sources

bioRxiv2025

Increased MALAT1 Levels in Thyroid Cancer are Linked to Metabolic Reprogramming and Lymphatic Infiltration in Chilean population

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA (lncRNA) implicated in cancer progression. In thyroid cancer, MALAT1 has been proposed as a potential biomarker, but its role in disease progression remains incompletely understood. Here, we analyzed MALAT1 RNA levels in paired tumoral and adjacent non-tumoral thyroid samples from a Chilean patient cohort. We found a positive correlation of MALAT1 levels with lymphatic infiltration that was not replicated when modeling MALAT1 expression in a larger cohort obtained from the TCGA-THCA database. An exploratory RNA-seq comparison of one matched tumor-adjacent tissue pair confirmed higher tumor abundance of MALAT1 and the epithelial-to-mesenchymal transition-marker VIM, together with lower abundance of cell-adhesion gene PCDH10. To investigate the impact of MALAT1 on thyroid cancer and cellular metabolism, we targeted MALAT1 in the papillary thyroid cancer cell line TPC1. MALAT1 knock-down reduced proliferation and migration while enhancing mitochondrial respiration with no changes in glycolysis. Notably, although MALAT1 was not localized within mitochondria, its silencing modulated the expression of transcripts associated with mitochondrial dynamics and mitophagy. Consistent with these results, transcriptomic correlation analysis in the TCGA-THCA cohort showed that MALAT1 expression was largely uncoupled from oxidative phosphorylation and glycolysis gene programs, while negatively correlating with core regulators of mitophagy and mitochondrial dynamics, pointing to a link with mitochondrial quality control rather than direct bioenergetic reprogramming. Our findings highlight MALAT1 as a contributor to thyroid cancer aggressiveness and reveal a link between MALAT1 and mitochondrial quality control independent of direct mitochondrial localization. Besides, our results support a tissue-specific mechanism and population-specific role of MALAT1 in cancer biology.

cancer biology↗

bioRxiv2024

FAM162A is Crucial for Mitochondrial Structure, Dynamics, and Bioenergetics, Driving Cellular Protection and Longevity

IntroductionFAM162A is a mitochondrial protein evolutionarily conserved across taxa and ubiquitously expressed in various tissues. It is known for its role in hypoxia-induced apoptosis. However, paradoxically, FAM162A is overexpressed in cancer, where its pro-apoptotic function seems overridden, suggesting an alternative role associated with mitochondrial function and cell survival. Additionally, its precise localization and topology remain controversial. ObjectivesTo assess the role of FAM162A in mitochondrial structure, dynamics, and bioenergetics and its impact on cell viability, while establishing its precise localization, orientation, and topology. Additionally, to generate a transgenic Drosophila model overexpressing human FAM162A to evaluate its effects on organismal survival under normal and stress conditions. MethodsLocalization, orientation, and topology were determined by protease protection assays in COS7 cells. Loss-and gain-of-function experiments were performed to assess mitochondrial function and turnover by confocal microscopy, immunoblots and Seahorse technology. A transgenic Drosophila model overexpressing human FAM162A was generated to evaluate organismal survival under normal and stress conditions. ResultsFAM162A is essential for maintaining mitochondrial ultrastructure and bioenergetics, thereby influencing cell viability and stress resistance. Localization studies revealed that FAM162A resides predominantly in the inner mitochondrial membrane, particularly within the cristae, where it modulates the fusion protein OPA1. Transgenic Drosophila overexpressing human FAM162A exhibited increased lifespan and locomotor activity under both normal and heat stress conditions. ConclusionFAM162A emerges as a crucial player in maintaining mitochondrial integrity and bioenergetics. Its functional role, potentially mediated through interaction with OPA1, impacts mitochondrial health, stress resistance, cellular viability, and organismal longevity.

cell biology↗

bioRxiv2020

Exacerbation of mitochondrial fission in human CD34+ cells halts erythropoiesis and hemoglobin biosynthesis

Erythropoiesis is the most powerful cellular differentiation and proliferation system, with a production of 1011 cells per day. In this fine-tuned process, the hematopoietic stem cells (HSCs) generate erythroid progenitors, which proliferate and mature into erythrocytes. During erythropoiesis, mitochondria are reprogrammed to drive the differentiation process before finally being eliminated by mitophagy. In erythropoiesis, mitochondrial dynamics (MtDy) is expected to be a regulatory key point that has not been described previously. We described that a specific MtDy pattern is occurring in human erythropoiesis from EPO-induced human CD34+ cells, characterized by a predominant mitochondrial fusion at early stages followed by predominant fission at late stages. The fusion protein MFN1 and the fission protein FIS1 are shown to play a key role in the accurate progression of erythropoiesis. Fragmentation of the mitochondrial web by the overexpression of FIS1 (gain of fission) resulted in both the inhibition of hemoglobin biosynthesis and the arrest of erythroid differentiation, keeping cells in immature differentiation stages. These cells showed specific mitochondrial features as compared with control cells, such as an increase in round and large mitochondria morphology, low mitochondrial membrane potential and a drop in the expression of the respiratory complexes II and IV. Interestingly, treatment with the mitochondrial permeability transition pore (mPTP) inhibitor cyclosporin A, rescued mitochondrial morphology, hemoglobin biosynthesis and erythropoiesis. Studies presented in this work revealed MtDy as a hot spot in the regulation of erythroid differentiation which might be signaling downstream for metabolic reprogramming through the aperture/close of the mPTP. Key Points-. Excessive fission disrupts erythroid progression, heme biosynthesis and mitochondrial function, keeping cells mostly in progenitors and proerythroblast stage. -. Mitochondrial Dynamics signaling for erythroid differentiation involves FIS1 and the mPTP

cell biology↗