Biology subjects

Villalba, J. M.

Publications and source records attributed to Villalba, J. M..

4 recordsLinked to original sources

bioRxiv2026

Differentiation protocol and maturation shape the axial identity and synaptic state in human iPSC-derived spinal motor neurons

Human induced pluripotent stem cell (iPSC)-derived motor neurons are widely used for disease modeling. Stem cells can be differentiated into motor neurons by exposure to specific patterning morphogens, which can ultimately determine terminal cellular composition and developmental state. We compared two small molecule workflows for human iPSC maturation into motor neurons: a rapid direct protocol (diMN protocol) and an extended protocol (purMN protocol), with both protocols matched for 20 days in maturation medium. While the diMN protocol generated mixed neural cultures, the purMN protocol provided cultures with greater motor neuron enrichment, stronger caudal spinal identity, broader synaptic and cholinergic programs, and reduced progenitor-associated signatures. By extending the purMN protocol to 32 days in maturation media, cultures developed reinforced spinal, postsynaptic, presynaptic, calcium-signaling, and cholinergic features. Across four independent reference frameworks, deconvolution aligned diMN cultures with anterior and progenitor-associated states and purMN cultures with spinal and post-mitotic states. In a microfluidic co-culture system, purMNs formed denser, more highly branched distal neurite networks and produced more innervated acetylcholine receptor clusters compared to diMNs. Revealing how purity and maturation jointly define the transcriptomic and structural state of human iPSC-derived spinal motor neuron cultures will help the field choose optimal models for studies of neurodevelopment and neurodegenerative diseases.

neuroscience↗

bioRxiv2025

SARS-CoV-2 ORF7a Drives Mitochondrial Dysfunction via PDK4 Activation and Complex I Inhibition

SARS-CoV-2 reprograms host metabolism to promote viral replication and evade immune responses. While infection is known to impair mitochondrial function and enhance glycolysis, the role of viral accessory proteins in these alterations remains unclear. Here, we investigate the metabolic impact of the accessory protein ORF7a. Lentiviral expression of ORF7a in human lung epithelial (A549) and monocytic (THP1) cells, coupled with integrated transcriptomic, proteomic, and metabolomic analyses, revealed profound dysregulation of glucose and lipid metabolism. ORF7a impaired oxidative phosphorylation, reducing basal and maximal respiration, inducing mitochondrial depolarization, and increasing reactive oxygen species. Mechanistically, ORF7a upregulated pyruvate dehydrogenase kinase 4 (PDK4), promoting pyruvate dehydrogenase (PDH) complex phosphorylation and suppressing pyruvate oxidation. However, pharmacological PDK4 inhibition did not restore respiration. High-resolution respirometry in frozen samples revealed impaired complex I function, while Blue Native-PAGE demonstrated defective respiratory supercomplex assembly. By linking enzymatic inhibition with structural destabilization, our study uncovers a functional vulnerability of the mitochondrial respiratory chain to viral manipulation. These findings establish ORF7a as a key modulator of host metabolic reprogramming and highlight mitochondrial pathways as potential therapeutic targets in COVID-19.

immunology↗

bioRxiv2024

Calcium (Ca2+) fluxes at Mitochondria-ER Contact Sites (MERCS) are a new target of senolysis in Therapy-Induced Senescence (TIS).

O_LIThis study investigates the state of calcium (Ca2+) flux and Mitochondria-ER contact sites (MERCS) on Therapy-Induced Senescence (TIS). C_LIO_LITIS cells-induced by Doxorubicin and Etoposide increase their MERCS contact surface but exhibit a decreased ER-mitochondria Ca2+ flux. C_LIO_LITIS cells show decreased levels of IP3R isoforms and a decreased interaction between type 1 IP3R isoform and VDAC1. C_LIO_LIThe ER-mitochondria Ca2+ flux is essential to maintain the viability of senescence cells. C_LIO_LIInhibition of ER-mitochondria Ca2+ flux rise as a new target of senolysis in vitro and in vivo. C_LI

cell biology↗

bioRxiv2023

Metabolic and mitochondria alterations induced by SARS-CoV-2 accessory proteins ORF3a, ORF9b, ORF9c and ORF10

Antiviral signaling, immune response and cell metabolism in human body are dysregulated by SARS-CoV-2, the causative agent of the COVID-19. Here, we show that SARS-CoV-2 accessory proteins ORF3a, ORF9b, ORF9c and ORF10 induce a significant mitochondrial and metabolic reprogramming in A549 lung epithelial cells. While all four ORFs caused mitochondrial fragmentation and altered mitochondrial function, only ORF3a and ORF9c induced a marked structural alteration in mitochondrial cristae. ORF9b, ORF9c and ORF10 induced largely overlapping transcriptomes. In contrast, ORF3a induced a distinct transcriptome, including the downregulation of numerous genes for proteins with critical mitochondrial functions and morphology. Genome-Scale Metabolic Models predicted common and private metabolic flux reprogramming, notably a depressed amino acid metabolism, and an enhanced metabolism of specific lipids distinctly induced by ORF3a. These findings reveal metabolic dependencies and vulnerabilities prompted by SARS-CoV-2 accessory proteins that may be exploited to identify new targets for intervention. One-Sentence SummaryMitochondria and metabolic alterations induced by SARS- CoV-2 accessory proteins ORF3a, ORF9b, ORF9c, ORF10 in pulmonary cells unravel new targets of intervention.

immunology↗