Presentation Title

Transcriptomic analysis of PAX5-induced MCOLN2 expression reveals a potential approach to restrict reactive gliosis in Mucolipidosis IV brain

Faculty Mentor

Math Cuajungco

Start Date

17-11-2018 8:30 AM

End Date

17-11-2018 10:30 AM

Location

CREVELING 75

Session

POSTER 1

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Mucolipidosis type IV (MLIV) is a lysosomal storage disorder caused by mutations or deletions in the Mucolipin-1 (MCOLN1) gene, encoding the transient receptor potential Mucolipin-1 (TRPML1) protein. TRPML1 belongs to a subfamily of cation channels that includes TRPML2 and -3, encoded by MCOLN2, and -3 genes, respectively. MLIV is characterized by cognitive and psycho-motor issues and affects mostly children and young adults of Ashkenazi Jewish descent. Recently, it was shown that the cerebral cortex and cerebellum of Mcoln1 knockout mice exhibit extensive gliosis, which is consistent with inflammatory response. It is not clear, however, whether inflammation is the cause or consequence of MLIV. Due to a high degree of sequence homology, we propose that TRPML2 could substitute for the loss of functional TRPML1 in MLIV, potentially rescuing the disease. As a proof-of-principle, we used MCOLN2’s transcription factor called PAX5 to induce its expression in human neuroglioma cells using adenovirus. We found that PAX5 up-regulated endogenous MCOLN2 transcripts as evidenced by standard polymerase chain reaction (PCR) and real-time quantitative PCR. To study the effects of PAX5-induced upregulation of MCOLN2 transcripts on global gene expression, we collected total RNA from treated and control cells for subsequent paired-end RNA sequencing (RNA-seq). We performed transcriptome analysis using commercial and open-source software. Preliminary enrichment analysis of RNA-seq data revealed marked reductions in gene ontology (GO) terms pertaining to cytokine production and innate/adaptive immune responses in PAX5-treated cells compared to negative controls. Experimental validation of the GO list showing down-regulated expression due to PAX5-induced MCOLN2 expression is currently being done using real-time quantitative PCR. Given the growing evidence implicating early gliosis caused by aberrant pro-inflammatory cytokine production as a contributor to disease pathogenesis or progression in MLIV mouse model, our results indicate that forced induction of endogenous MCOLN2 expression in human glial cells may potentially ameliorate some of the pathologic changes in MLIV. Future studies on forced induction of Mcoln2 in Mcoln1 knockout mouse brain could open new research avenues to determine whether Trpml2 could dampen down gliosis and possibly prevent the progressive neurodegeneration in MLIV.

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Nov 17th, 8:30 AM Nov 17th, 10:30 AM

Transcriptomic analysis of PAX5-induced MCOLN2 expression reveals a potential approach to restrict reactive gliosis in Mucolipidosis IV brain

CREVELING 75

Mucolipidosis type IV (MLIV) is a lysosomal storage disorder caused by mutations or deletions in the Mucolipin-1 (MCOLN1) gene, encoding the transient receptor potential Mucolipin-1 (TRPML1) protein. TRPML1 belongs to a subfamily of cation channels that includes TRPML2 and -3, encoded by MCOLN2, and -3 genes, respectively. MLIV is characterized by cognitive and psycho-motor issues and affects mostly children and young adults of Ashkenazi Jewish descent. Recently, it was shown that the cerebral cortex and cerebellum of Mcoln1 knockout mice exhibit extensive gliosis, which is consistent with inflammatory response. It is not clear, however, whether inflammation is the cause or consequence of MLIV. Due to a high degree of sequence homology, we propose that TRPML2 could substitute for the loss of functional TRPML1 in MLIV, potentially rescuing the disease. As a proof-of-principle, we used MCOLN2’s transcription factor called PAX5 to induce its expression in human neuroglioma cells using adenovirus. We found that PAX5 up-regulated endogenous MCOLN2 transcripts as evidenced by standard polymerase chain reaction (PCR) and real-time quantitative PCR. To study the effects of PAX5-induced upregulation of MCOLN2 transcripts on global gene expression, we collected total RNA from treated and control cells for subsequent paired-end RNA sequencing (RNA-seq). We performed transcriptome analysis using commercial and open-source software. Preliminary enrichment analysis of RNA-seq data revealed marked reductions in gene ontology (GO) terms pertaining to cytokine production and innate/adaptive immune responses in PAX5-treated cells compared to negative controls. Experimental validation of the GO list showing down-regulated expression due to PAX5-induced MCOLN2 expression is currently being done using real-time quantitative PCR. Given the growing evidence implicating early gliosis caused by aberrant pro-inflammatory cytokine production as a contributor to disease pathogenesis or progression in MLIV mouse model, our results indicate that forced induction of endogenous MCOLN2 expression in human glial cells may potentially ameliorate some of the pathologic changes in MLIV. Future studies on forced induction of Mcoln2 in Mcoln1 knockout mouse brain could open new research avenues to determine whether Trpml2 could dampen down gliosis and possibly prevent the progressive neurodegeneration in MLIV.