Julieta M. Ramírez-Mejía

Ms. Julieta M. Ramírez-Mejía

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Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 September 2022 in Bioresource Technology Reports
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Journal Article
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PCPaula Daniela Cuadrado-Osorio
Paula Daniela Cuadrado-Osorio
Julieta M. Ramírez-MejíaJulieta M. Ramírez-Mejía
Julieta M. Ramírez-Mejía
LMLuis Fernando Mejía-Avellaneda
Luis Fernando Mejía-Avellaneda
LMLeyanis Mesa
Leyanis Mesa
EBEddy J Bautista
Eddy J Bautista

17 July 2022 in The Journal of Nutritional Biochemistry
Verified
Journal Article
Open access
GFGeysson Javier Fernandez
Geysson Javier Fernandez
Julieta M. Ramírez-MejíaJulieta M. Ramírez-Mejía
Julieta M. Ramírez-Mejía
SUSilvio Urcuqui-Inchima
Silvio Urcuqui-Inchima
Vitamin D is associated with the stimulation of innate immunity, inflammation, and host defense against pathogens. Macrophages express receptors of Vitamin D, regulating the transcription of genes related to immune processes. However, the transcriptional and post-transcriptional strategies controlling gene expression in differentiated macrophages, and how they are influenced by Vitamin D are not well understood. We studied whether Vitamin D enhances immune response by regulating the expression of microRNAs and mRNAs. Analysis of the transcriptome showed differences in expression of 199 genes, of which 68% were up-regulated, revealing the cell state of monocyte-derived macrophages differentiated with Vitamin D (D3-MDMs) as compared to monocyte-derived macrophages (MDMs). The differentially expressed genes appear to be associated with pathophysiological processes, including inflammatory responses, and cellular stress. Transcriptional motifs in promoter regions of up- or down-regulated genes showed enrichment of VDR motifs, suggesting possible roles of transcriptional activator or repressor in gene expression. Further, the microRNA-Seq analysis indicated that there were 17 differentially expressed miRNAs, of which, seven were up-regulated and 10 down-regulated, suggesting that Vitamin D plays a critical role in the regulation of miRNA expression during macrophages differentiation. The miR-6501-3p, miR-1273h-5p, miR-665, miR-1972, miR-1183, miR-619-5p were down-regulated in D3-MDMs compared to MDMs. The integrative analysis of miRNA and mRNA expression profiles predicts that miR-1972, miR-1273h-5p, and miR-665 regulate genes PDCD1LG2, IL-1B, and CD274, which are related to the inflammatory response. Results suggest an essential role of Vitamin D in macrophage differentiation that modulates host response against pathogens, inflammation, and cellular stress.

5 May 2023 in International Immunopharmacology
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Journal Article
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GFGeysson Javier Fernandez
Geysson Javier Fernandez
Julieta M. Ramírez-MejíaJulieta M. Ramírez-Mejía
Julieta M. Ramírez-Mejía
JCJorge Andrés Castillo
Jorge Andrés Castillo
SUSilvio Urcuqui-Inchima
Silvio Urcuqui-Inchima

17 October 2022 in The International Journal of Biochemistry & Cell Biology
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Journal Article
Closed access
GFGeysson Javier Fernandez
Geysson Javier Fernandez
Julieta M. Ramírez-MejíaJulieta M. Ramírez-Mejía
Julieta M. Ramírez-Mejía
SUSilvio Urcuqui-Inchima
Silvio Urcuqui-Inchima

30 November 2025 in Biology
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YOYina Tatiana Zambrano Ordoñez
Yina Tatiana Zambrano Ordoñez
AMAlejandro Mejía-Garcia
Alejandro Mejía-Garcia
Julieta M. Ramírez-MejíaJulieta M. Ramírez-Mejía
Julieta M. Ramírez-Mejía
HTHsuan Megan Tsao
Hsuan Megan Tsao
PMPaula D. Morales-Suárez
Paula D. Morales-Suárez
Carlos Alberto OrozcoCarlos Alberto Orozco
Carlos Alberto Orozco
Breast cancer (BC) is a heterogeneous disease, and triple-negative breast cancer (TNBC) is the most aggressive and immunogenic subtype. A significant proportion of TNBC cases are linked to hereditary cancer syndromes involving pathogenic germline variants, most commonly in BRCA1/2. However, few studies have compared hereditary and sporadic TNBC in admixed populations. In this study, molecular and immunological features were analyzed through the analysis of 62 Colombian TNBC samples (20 hereditary and 42 sporadic cases) by RNA sequencing to identify molecular and immune differences. We used an external validation cohort of 16 TCGA TNBC cases (8 BRCA-mutated and 8 non-mutated) to replicate our findings. Results: We found a set of 921 differentially expressed genes (DEGs) between hereditary and sporadic TNBC. Hereditary tumors were enriched for pathways related to extracellular matrix (ECM) remodeling, structural components, and DNA damage response and exhibited a more immunologically active tumor microenvironment compared to sporadic tumors. LASSO logistic regression identified 23 genes with discriminatory potential, showing that hereditary tumors are characterized by complex immune regulation, inflammatory processes, and activation of key oncogenic pathways. Conclusions: Hereditary TNBC is characterized by molecular and biological functions linked to ECM remodeling and its constituents and an active immune microenvironment. This integrated molecular–immune profile provides insight into the distinct biology of hereditary tumors in admixed populations.

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LCLuiza Cortes
Luiza Cortes
ARAna Beatriz Rodrigues
Ana Beatriz Rodrigues
SBSARA MARTORELI DA SILVEIRA BINATO
SARA MARTORELI DA SILVEIRA BINATO
Julieta M. Ramírez-MejíaJulieta M. Ramírez-Mejía
Julieta M. Ramírez-Mejía
CDCarine Spenassatto Dreyer
Carine Spenassatto Dreyer
SRSilvia Rogatto
Silvia Rogatto
Testicular germ cell tumor (TGCT) is a common tumor type in young men. Family history of TGCT and its presence in twins support the involvement of inherited genetic factors. Germline exome sequencing was performed on monozygotic twins with TGCT and their parents. The twins presented compound heterozygous variants in PDE11A (rs776984134 and rs17400325) inherited from each parent. The rs776984134 variant disrupts the canonical splice acceptor site, leading to aberrant splicing and a frameshift predicted to affect protein structure. The rs17400325 missense variant, located in the catalytic domain, reduces hydrogen bonding capacity and may impair protein stability. Both variants map to a genomic region overlapping the antisense lncRNA PDE11A-AS1. In silico transcript-level analysis predicted multiple energetically favorable RNA–RNA interactions between PDE11A and PDE11A-AS1 transcripts, with rs17400325 located within predicted hybridization regions of several isoforms. These results suggest a potential impact on PDE11A–PDE11A-AS1 pairing and post-transcriptional regulation. Additional variants in MSH6 and CTU2 were also identified and may act as potential modifiers of disease susceptibility, consistent with a multigenic contribution to TGCT risk. These findings support a contributory role for the PDE11A locus in TGCT predisposition and underscore the biological relevance of overlapping sense–antisense genomic regions in hereditary cancer studies.