Carlos Javier Alméciga-Díaz

Background: Metastasis is the leading cause of mortality in lung cancer and is regulated by multiple molecular mechanisms, including microRNAs (miRNAs). Although cancer stem cells (CSCs) and epithelial–mesenchymal transition (EMT) contribute to metastatic progression, the miRNA networks underlying these phenotypes remain poorly characterized in non-small cell lung cancer (NSCLC). Aim: To identify miRNA signatures associated with CSCs and EMT in NSCLC and functionally characterize hsa-let-7a-3p. Methods: EMT was induced in A549 and NCI-H1975 cells by dCas9-mediated activation of TWIST, whereas CSC-enriched populations were generated by CD133-based sorting and stem cell culture conditions. Small RNA sequencing, bioinformatic analyses, qPCR validation, and functional assays were performed to identify and characterize phenotype-associated miRNAs. Results: Small RNA sequencing identified distinct miRNA expression profiles associated with EMT and CSC enrichment. Comparative analysis identified 13 commonly downregulated and 13 commonly upregulated miRNAs shared by CSCs from A549 and H1975 cells, suggesting conserved post-transcriptional regulatory mechanisms. Functional enrichment and miRNA–target interaction network analyses linked the miRNA signatures to pathways involved in epithelial plasticity, stemness, and tumor progression, including Wnt, TGF-β, mTOR, focal adhesion, adherens junction, and regulation of the actin cytoskeleton. Among the dysregulated miRNAs, hsa-let-7a-3p was consistently upregulated in CD133⁺ CSC-enriched cells from both NSCLC cell lines. Functional assays showed that hsa-let-7a-3p overexpression significantly reduced clonogenic capacity and showed a trend toward decreased invasion without affecting proliferation. Conclusion: This study identifies miRNA signatures associated with CSC-enriched and EMT-associated phenotypes in NSCLC and demonstrates that these signatures represent coordinated post-transcriptional regulatory programs involved in epithelial plasticity, stemness, and metastatic progression. Functional validation of hsa-let-7a-3p further supports its role as a context-dependent regulator of CSC biology and highlights the potential of miRNA signatures as diagnostic biomarkers in NSCLC.

Tay-Sachs disease is a rare genetic disorder characterized by the accumulation of GM2 ganglioside in neuronal lysosomes due to deficient β-hexosaminidase A (HexA) activity. Progressive GM2 storage leads to severe neurodegeneration, including developmental delay, motor weakness, seizures, ataxia, and early death, typically by five years of age. Previous studies have elucidated several neuronal mechanisms, including apoptosis, endoplasmic reticulum stress, neuroinflammation, and demyelination, these investigations have focused almost exclusively on neurons. However, other components of the central nervous system, particularly astroglia, may play a critical role in disease pathophysiology as suggested by studies in related lysosomal storage disorders. To address this gap, we generated an astrocyte-like model deficient in HexA by targeted knockdown of the HEXA gene in U87MG astrocytoma cells. The resulting cell line recapitulates key pathological features, including lysosomal accumulation, increased neutral lipid content, reduced mitochondrial mass, and elevated reactive oxygen species production. Transcriptomic analysis revealed significant alterations in pathways associated with neuronal degeneration, synaptic organization, mitochondrial dysfunction, and ganglioside metabolism. In summary, this model reproduces some classical cellular alterations reported in Tay-Sachs disease and could potentially provide novel insight into astrocyte involvement in its pathophysiology. These findings support the relevance of non-neuronal cells in disease pathophysiology and establish this system as a valuable platform for screening potential novel mechanisms and therapeutic approaches. Furthermore, this approach highlights the importance of integrating cell type specific models to better understand disease heterogeneity and providing insights into the progressive neurodegeneration of Tay-Sachs disease, positioning this model as a valuable tool for studying its underlying pathophysiology.

The interaction of a set of four N-acetyl-glucosamine (GlcNAc) glycomimetics with human N-acetyl-glucosaminidase (NAGLU), the genetically defective enzyme in patients suffering from mucopolysaccharidosis (MPS) IIIB, also known as Sanfilippo B syndrome, was investigated to identify potential pharmacological chaperones. Glycomimetic–NAGLU binding was initially studied by molecular docking simulations and a thermal shift assay. The effects of the glycomimetics on NAGLU activity enhancement were studied in fibroblast cells from seven MPS IIIB patients. A significant increase in NAGLU activity in four cell lines in the presence of glycomimetic MK 8719, a molecule tested in a Phase 1 study in healthy volunteers to treat Alzheimer’s disease, was demonstrated. Furthermore, MK 8719 prevented the increase in glycosaminoglycan (GAG) levels in four MPS IIIB fibroblast cells, suggesting that this molecule may be worth investigating further as a pharmacological chaperone for MPS IIIB. These results represent an important contribution towards the development of a specific therapy for MPS IIIB.

Background: Tay–Sachs disease (TSD) is an autosomal recessive lysosomal storage disorder characterized by the accumulation of GM2 ganglioside due to mutations in the HEXA gene, which encodes the α-subunit of β-Hexosaminidase A. This accumulation leads to significant neuropathological effects and premature death in affected individuals. No effective treatments exist, but enzyme replacement therapies are under investigation. In our previous work, we demonstrated the internalization and efficacy of human recombinant lysosomal β-hexosaminidase A (rhHex-A), produced in the methylotrophic yeast Pichia pastoris, in reducing lipids and lysosomal mass levels in fibroblasts and neural stem cells derived from patient-induced pluripotent stem cells (iPSCs). In this study, we further evaluated the potential of rhHex-A to prevent GM2 accumulation using fibroblast and neuroglia cells from a TSD patient alongside a relevant mouse model. Methods: Fibroblasts and neuroglial cell lines derived from a murine model and TSD patients were treated with 100 nM rhHexA for 72 h. After treatment, cells were stained by anti-GM2 (targeting GM2 ganglioside; KM966) and anti-LAMP1 (lysosomal-associated membrane protein 1) colocalization staining and incubated with 50 nM LysoTracker Red DND-99 to label lysosomes. In addition, GM2AP and HEXB expression were analyzed to assess whether rhHex-A treatment affected the levels of enzymes involved in GM2 ganglioside degradation. Results: Immunofluorescence staining for LysoTracker and colocalization studies of GM2 and Lamp1 indicated reduced lysosomal mass and GM2 levels. Notably, rhHex-A treatment also affected the expression of the HEXB gene, which is involved in GM2 ganglioside metabolism, highlighting a potential regulatory interaction within the metabolic pathway. Conclusions: Here, we report that rhHex-A produced in yeast can efficiently degrade GM2 ganglioside and rescue lysosomal accumulation in TSD cells.

Background/Objectives: Tay–Sachs disease (TSD) is a neurodegenerative disorder caused by a deficiency in β-hexosaminidase A (HexA), which accumulates GM2 gangliosides, primarily in neurons. Currently, therapeutic options are limited, highlighting the need for new strategies such as gene therapy. Despite their effectiveness, viral vectors can elicit adverse immune responses; consequently, non-viral vectors are being explored as an alternative. We have previously investigated the use of CRISPR/Cas9 nickase (nCas9) as a potential tool for treating TSD. Here, we expanded our study by evaluating the PP6D5 polymer as a novel non-viral vector for delivering the CRISPR/nCas9 system to restore HexA activity. Methods: First, we evaluated the PP6D5-mediated CRISPR/nCas9 system’s transfection efficiency in NIH-3T3 fibroblasts, U87MG astrocytoma, SHSY5Y neuroblastoma, and TSD fibroblasts. We then evaluated the potential of PP6D5 to correct the gene defect in TSD fibroblasts. Results: The results showed that PP6D5 exhibited significantly higher transfection efficiency compared to lipofectamine 3000 in all tested cell models. In TSD fibroblasts, transfection with both HEXA and HEXB cDNAs increased the HexA activity levels by up to 7.4-fold, compared to a 3.2-fold increase in cells transfected only with HEXA cDNA after 15 days post-transfection. These levels were up to 4.5-fold higher than those observed in lipofectamine-mediated transfection. Additionally, PP6D5-mediated CRISPR/nCas9-based genome editing led to a significant reduction in the lysosomal mass of TSD fibroblasts. Conclusions: This study provides promising evidence for the use of the PP6D5 polymer as a non-viral vector for delivering CRISPR/nCas9-based gene therapy in TSD. The use of the PP6D5 polymer may offer some advantages that viral vectors cannot, such as a reduction in cytotoxicity and higher TE in difficult-to-transfect cell lines. Furthermore, this type of polymeric vector has not been extensively explored for gene therapy, making this study an important contribution to the development of non-viral delivery systems for the treatment of neurodegenerative diseases.

Mucopolysaccharidosis (MPS) IVA is a bone-affecting lysosomal storage disease (LSD) caused by impaired degradation of the glycosaminoglycans (GAGs) keratan sulfate (KS) and chondroitin 6-sulfate (C6S) due to deficient N-acetylgalactosamine-6-sulfatase (GALNS) enzyme activity. Previously, we successfully developed and validated a CRISPR/nCas9-based gene therapy (GT) to insert an expression cassette at the AAVS1 and ROSA26 loci in human MPS IVA fibroblasts and MPS IVA mice, respectively. In this study, we have extended our approach to evaluate the effectiveness of our CRISPR/nCas9-based GT in editing human CD34+ cells to mediate cross-correction of MPS IVA fibroblasts. CD34+ cells were electroporated with the CRISPR/nCas9 system, targeting the AAVS1 locus. The nCas9-mediated on-target donor template insertion, and the stemness of the CRISPR/nCas-edited CD34+ cells was evaluated. Additionally, MPS IVA fibroblasts were co-cultured with CRISPR/nCas-edited CD34+ cells to assess cross-correction. CRISPR/nCas9-based gene editing did not affect the stemness of CD34+ cells but did lead to supraphysiological levels of the GALNS enzyme. Upon co-culture, MPS IVA fibroblasts displayed a significant increase in the GALNS enzyme activity along with lysosomal mass reduction, pro-oxidant profile amelioration, mitochondrial mass recovery, and pro-apoptotic and pro-inflammatory profile improvement. These results show the potential of our CRISPR/nCas9-based GT to edit CD34+ cells to mediate cross-correction.

Mucopolysaccharidosis IVA is a lysosomal storage disease caused by mutations in the gene encoding for the hydrolase N-acetylgalactose-6-sulfate sulfatase (GALNS). GALNS deficiency leads to a progressive buildup of partially degraded chondroitin-6-sulfate and keratan-6-sulfate within the lysosomes. Several therapeutic strategies are under evaluation. Recently, we validated the use of a CRISPR/Cas9 nickase-based GT for MPS IVA, recovering up to 40% of normal GALNS activity, which had a positive outcome on classical MPS IVA biomarkers. In this study, we extended our previous findings by using the co-delivery of the CRISPR/Cas9 system with the proteins E4orf6 or E1B, which are inhibitors of the non-homologous end-joining repair pathway that may favor an increase in the homology-directed repair mechanism. The CRISPR/Cas9 vectors were transfected on GM00593 and GM01361 human MPS IVA fibroblasts by using a lipofection-based delivery. After 30 days post-transfection with CRISPR/Cas9 systems in absence of the E4orf6 or E1B, we found an increase in the GALNS activity up to 4.17 and 11.2-fold when compared to untreated controls, for GM01361 and GM00593 respectively. Partial recovery of the lysosomal mass was achieved in human MPS IVA fibroblasts after treatment, while a modest reduction in oxidative stress was observed only for GM01361. Non-improvement on those parameters was detected when CRISPR/Cas9 plasmids expressing E4orf6 or E1B were transfected. Together, our results support the use of CRISPR/Cas9 as a potential GT-based strategy for the treatment of MPS IVA and highlight the importance of continuing to seek strategies to improve the impact of gene editing as a therapeutic approach.