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International Journal of Molecular... Sep 2023Type 2 diabetes mellitus is a chronic metabolic disease with no cure. Adipose tissue is a major site of systemic insulin resistance. Sortilin is a central component of...
Type 2 diabetes mellitus is a chronic metabolic disease with no cure. Adipose tissue is a major site of systemic insulin resistance. Sortilin is a central component of the glucose transporter -Glut4 storage vesicles (GSV) which translocate to the plasma membrane to uptake glucose from circulation. Here, using human adipocytes we demonstrate the presence of the alternatively spliced, truncated sortilin variant (Sort_T) whose expression is significantly increased in diabetic adipose tissue. Artificial-intelligence-based modeling, molecular dynamics, intrinsically disordered region analysis, and co-immunoprecipitation demonstrated association of Sort_T with Glut4 and decreased glucose uptake in adipocytes. The results show that glucagon-like peptide-1 (GLP1) hormone decreases Sort_T. We deciphered the molecular mechanism underlying GLP1 regulation of alternative splicing of human sortilin. Using splicing minigenes and RNA-immunoprecipitation assays, the results show that GLP1 regulates Sort_T alternative splicing via the splice factor, TRA2B. We demonstrate that targeted antisense oligonucleotide morpholinos reduces Sort_T levels and improves glucose uptake in diabetic adipocytes. Thus, we demonstrate that GLP1 regulates alternative splicing of sortilin in human diabetic adipocytes.
Topics: Humans; Alternative Splicing; Diabetes Mellitus, Type 2; Adipocytes; Glucagon-Like Peptide 1; Glucose
PubMed: 37762628
DOI: 10.3390/ijms241814324 -
Molecular Therapy. Nucleic Acids Dec 2023Myotonic dystrophy type 1 (DM1) is a rare neuromuscular disease caused by a CTG repeat expansion in the gene that generates toxic RNA with a myriad of downstream...
Myotonic dystrophy type 1 (DM1) is a rare neuromuscular disease caused by a CTG repeat expansion in the gene that generates toxic RNA with a myriad of downstream alterations in RNA metabolism. A key consequence is the sequestration of alternative splicing regulatory proteins MBNL1/2 by expanded transcripts in the affected tissues. MBNL1/2 depletion interferes with a developmental alternative splicing switch that causes the expression of fetal isoforms in adults. Boosting the endogenous expression of MBNL proteins by inhibiting the natural translational repressors miR-23b and miR-218 has previously been shown to be a promising therapeutic approach. We designed antimiRs against both miRNAs with a phosphorodiamidate morpholino oligonucleotide (PMO) chemistry conjugated to cell-penetrating peptides (CPPs) to improve delivery to affected tissues. In DM1 cells, CPP-PMOs significantly increased MBNL1 levels. In some candidates, this was achieved using concentrations less than two orders of magnitude below the median toxic concentration, with up to 5.38-fold better therapeutic window than previous antagomiRs. In mice, intravenous injections of CPP-PMOs improve molecular, histopathological, and functional phenotypes, without signs of toxicity. Our findings place CPP-PMOs as promising antimiR candidates to overcome the treatment delivery challenge in DM1 therapy.
PubMed: 37744174
DOI: 10.1016/j.omtn.2023.09.001 -
Genome Research Aug 2023Cys2-His2 zinc finger genes (ZNFs) form the largest family of transcription factors in metazoans. ZNF evolution is highly dynamic and characterized by the rapid...
Cys2-His2 zinc finger genes (ZNFs) form the largest family of transcription factors in metazoans. ZNF evolution is highly dynamic and characterized by the rapid expansion and contraction of numerous subfamilies across the animal phylogeny. The forces and mechanisms underlying rapid ZNF evolution remain poorly understood, but there is growing evidence that, in tetrapods, the targeting and repression of lineage-specific transposable elements (TEs) plays a critical role in the evolution of the Krüppel-associated box ZNF (KZNF) subfamily. Currently, it is unknown whether this function and coevolutionary relationship is unique to KZNFs or is a broader feature of metazoan ZNFs. Here, we present evidence that genomic conflict with TEs has been a central driver of the diversification of ZNFs in animals. Sampling from 3221 genome assemblies, we show that the copy number of retroelements correlates with that of ZNFs across at least 750 million years of metazoan evolution. Using computational predictions, we show that ZNFs preferentially bind TEs in diverse animal species. We further investigate the largest ZNF subfamily found in cyprinid fish, which is characterized by a conserved sequence we dubbed the fish N-terminal zinc finger-associated (FiNZ) domain. Zebrafish possess approximately 700 FiNZ-ZNFs, many of which are evolving adaptively under positive selection. Like mammalian KZNFs, most zebrafish FiNZ-ZNFs are expressed at the onset of zygotic genome activation, and blocking their translation using morpholinos during early embryogenesis results in derepression of transcriptionally active TEs. Together, these data suggest that ZNF diversification has been intimately connected to TE expansion throughout animal evolution.
Topics: Animals; DNA Transposable Elements; Zebrafish; Zinc Fingers; Transcription Factors; Mammals; Evolution, Molecular
PubMed: 37714714
DOI: 10.1101/gr.277966.123 -
International Journal of Molecular... Sep 2023Sialidases remove terminal sialic acids residues from the non-reducing ends of glycoconjugates. They have been recognized as catabolic enzymes that work within different...
Sialidases remove terminal sialic acids residues from the non-reducing ends of glycoconjugates. They have been recognized as catabolic enzymes that work within different subcellular compartments and can ensure the proper turn-over of glycoconjugates. Four mammalian sialidases (NEU1-4) exist, with different subcellular localization, pH optimum and substrate specificity. In zebrafish, seven different sialidases, with high homology to mammalian counterparts, have been identified. Zebrafish Neu3.2 is similar to the human cytosolic sialidase NEU2, which is involved in skeletal muscle differentiation and exhibits a broad substrate specificity toward gangliosides and glycoproteins. In zebrafish , mRNA is expressed during somite development, and its enzymatic activity has been detected in the skeletal muscle and heart of adult animals. In this paper, 1-4-cell-stage embryos injected with splice-blocking morpholino showed severe embryonic defects, mainly in somites, heart and anterior-posterior axis formation. and expressions were altered in morphants, and impaired musculature formation was associated with a defective locomotor behavior. Finally, the co-injection of mouse mRNA in morphants rescued the phenotype. These data are consistent with the involvement of cytosolic sialidase in pathologies related to muscle formation and support the validity of the model to investigate the pathogenesis of the diseases.
Topics: Animals; Down-Regulation; Muscle Development; Muscle, Skeletal; Neuraminidase; Zebrafish; Zebrafish Proteins
PubMed: 37686385
DOI: 10.3390/ijms241713578 -
Blood Nov 2023Aberrant skipping of coding exons in CD19 and CD22 compromises the response to immunotherapy in B-cell malignancies. Here, we showed that the MS4A1 gene encoding human...
Aberrant skipping of coding exons in CD19 and CD22 compromises the response to immunotherapy in B-cell malignancies. Here, we showed that the MS4A1 gene encoding human CD20 also produces several messenger RNA (mRNA) isoforms with distinct 5' untranslated regions. Four variants (V1-4) were detected using RNA sequencing (RNA-seq) at distinct stages of normal B-cell differentiation and B-lymphoid malignancies, with V1 and V3 being the most abundant. During B-cell activation and Epstein-Barr virus infection, redirection of splicing from V1 to V3 coincided with increased CD20 positivity. Similarly, in diffuse large B-cell lymphoma, only V3, but not V1, correlated with CD20 protein levels, suggesting that V1 might be translation-deficient. Indeed, the longer V1 isoform contained upstream open reading frames and a stem-loop structure, which cooperatively inhibited polysome recruitment. By modulating CD20 isoforms with splice-switching morpholino oligomers, we enhanced CD20 expression and anti-CD20 antibody rituximab-mediated cytotoxicity in a panel of B-cell lines. Furthermore, reconstitution of CD20-knockout cells with V3 mRNA led to the recovery of CD20 positivity, whereas V1-reconstituted cells had undetectable levels of CD20 protein. Surprisingly, in vitro CD20-directed chimeric antigen receptor T cells were able to kill both V3- and V1-expressing cells, but the bispecific T-cell engager mosunetuzumab was only effective against V3-expressing cells. To determine whether CD20 splicing is involved in immunotherapy resistance, we performed RNA-seq on 4 postmosunetuzumab follicular lymphoma relapses and discovered that in 2 of them, the downregulation of CD20 was accompanied by a V3-to-V1 shift. Thus, splicing-mediated mechanisms of epitope loss extend to CD20-directed immunotherapies.
Topics: Humans; Alternative Splicing; RNA, Messenger; 5' Untranslated Regions; Epstein-Barr Virus Infections; Herpesvirus 4, Human; Antigens, CD20; Protein Isoforms; Immunotherapy; Protein Biosynthesis; Neoplasms
PubMed: 37683180
DOI: 10.1182/blood.2023020400 -
Translational Vision Science &... Sep 2023To evaluate the pharmacology and toxicology of SAF312, a transient receptor potential vanilloid 1 (TRPV1) antagonist.
PURPOSE
To evaluate the pharmacology and toxicology of SAF312, a transient receptor potential vanilloid 1 (TRPV1) antagonist.
METHODS
TRPV1 expression in human ocular tissues was evaluated with immunohistochemistry. Inhibition of calcium influx in Chinese hamster ovary (CHO) cells expressing human TRPV1 (hTRPV1) and selectivity of SAF312 were assessed by a fluorescent imaging plate reader assay. Ocular tissue and plasma pharmacokinetics (PK) were assessed following a single topical ocular dose of SAF312 (0.5%, 1.0%, 1.5%, 2.5%) in rabbits. Safety and tolerability of SAF312 were evaluated in rabbits and dogs. Effects of SAF312 on corneal wound healing after photorefractive keratectomy (PRK) surgery were assessed in rabbits.
RESULTS
TRPV1 expression was noted in human cornea and conjunctiva. SAF312 inhibited calcium influx in CHO-hTRPV1 cells induced by pH 5.5 (2-[N-morpholino] ethanesulfonic acid), N-arachidonoylethanolamine, capsaicin, and N-arachidonoyl dopamine, with IC50 values of 5, 10, 12, and 27 nM, respectively, and inhibition appeared noncompetitive. SAF312 demonstrated high selectivity for TRPV1 (>149-fold) over other TRP channels. PK analysis showed highest concentrations of SAF312 in cornea and conjunctiva. SAF312 was found to be safe and well tolerated in rabbits and dogs up to the highest feasible concentration of 2.5%. No delay in wound healing after PRK was observed.
CONCLUSIONS
SAF312 is a potent, selective, and noncompetitive antagonist of hTRPV1 with an acceptable preclinical safety profile for use in future clinical trials.
TRANSLATIONAL RELEVANCE
SAF312, which was safe and well tolerated without causing delay in wound healing after PRK in rabbits, may be a potential therapeutic agent for ocular surface pain.
Topics: Animals; Cricetinae; Dogs; Humans; Rabbits; Calcium; CHO Cells; Conjunctiva; Cricetulus; TRPV Cation Channels
PubMed: 37672251
DOI: 10.1167/tvst.12.9.5 -
Journal of Cell Science Sep 2023Previous clinical studies and work in mouse models have indicated that platelets and microclots might enable the recruitment of immune cells to the pre-metastatic cancer...
Previous clinical studies and work in mouse models have indicated that platelets and microclots might enable the recruitment of immune cells to the pre-metastatic cancer niche, leading to efficacious extravasation of cancer cells through the vessel wall. Here, we investigated the interaction between platelets, endothelial cells, inflammatory cells, and engrafted human and zebrafish cancer cells by live-imaging studies in translucent zebrafish larvae, and show how clotting (and clot resolution) act as foci and as triggers for extravasation. Fluorescent tagging in each lineage revealed their dynamic behaviour and potential roles in these events, and we tested function by genetic and drug knockdown of the contributing players. Morpholino knockdown of fibrinogen subunit α (fga) and warfarin treatment to inhibit clotting both abrogated extravasation of cancer cells. The inflammatory phenotype appeared fundamental, and we show that forcing a pro-inflammatory, tnfa-positive phenotype is inhibitory to extravasation of cancer cells.
Topics: Animals; Mice; Humans; Endothelial Cells; Zebrafish; Neoplasms; Blood Coagulation; Thrombosis
PubMed: 37671502
DOI: 10.1242/jcs.261225 -
RNA Biology Jan 2023Mutations in the gene are causative for Duchenne muscular dystrophy (DMD). Antisense oligonucleotide (AON) mediated exon skipping to restore disrupted dystrophin...
Mutations in the gene are causative for Duchenne muscular dystrophy (DMD). Antisense oligonucleotide (AON) mediated exon skipping to restore disrupted dystrophin reading frame is a therapeutic approach that allows production of a shorter but functional protein. As DMD causing mutations can affect most of the 79 exons encoding dystrophin, a wide variety of AONs are needed to treat the patient population. Design of AONs is largely guided by trial-and-error, and it is yet unclear what defines the skippability of an exon. Here, we use a library of phosphorodiamidate morpholino oligomer (PMOs) AONs of similar physical properties to test the skippability of a large number of exons. The transcript is non-sequentially spliced, meaning that certain introns are retained longer in the transcript than downstream introns. We tested whether the relative intron retention time has a significant effect on AON efficiency, and found that targeting an out-of-frame exon flanked at its 5'-end by an intron that is retained in the transcript longer ('slow' intron) leads to overall higher exon skipping efficiency than when the 5'-end flanking intron is 'fast'. Regardless of splicing speed of flanking introns, we find that positioning an AON closer to the 5'-end of the target exon leads to higher exon skipping efficiency opposed to targeting an exons 3'-end. The data enclosed herein can be of use to guide future target selection and preferential AON binding sites for both DMD and other disease amenable by exon skipping therapies.
Topics: Humans; Oligonucleotides, Antisense; Introns; Dystrophin; Exons; Muscular Dystrophy, Duchenne
PubMed: 37667454
DOI: 10.1080/15476286.2023.2254041 -
BioRxiv : the Preprint Server For... Aug 2023Aberrant skipping of coding exons in CD19 and CD22 compromises responses to immunotherapy for B-cell malignancies. Here, we show that the gene encoding human CD20 also...
UNLABELLED
Aberrant skipping of coding exons in CD19 and CD22 compromises responses to immunotherapy for B-cell malignancies. Here, we show that the gene encoding human CD20 also produces several mRNA isoforms with distinct 5' untranslated regions (5'-UTR). Four variants (V1-4) were detectable by RNA-seq in distinct stages of normal B-cell differentiation and B-lymphoid malignancies, with V1 and V3 being the most abundant by far. During B-cell activation and Epstein-Barr virus infection, redirection of splicing from V1 to V3 coincided with increased CD20 positivity. Similarly, in diffuse large B-cell lymphoma only V3, but not V1, correlated with CD20 protein levels, suggesting that V1 might be translation-deficient. Indeed, the longer V1 isoform was found to contain upstream open reading frames (uORFs) and a stem-loop structure, which cooperatively inhibited polysome recruitment. By modulating CD20 isoforms with splice-switching Morpholino oligomers, we enhanced CD20 expression and anti-CD20 antibody rituximab-mediated cytotoxicity in a panel of B-cell lines. Furthermore, reconstitution of CD20-knockout cells with V3 mRNA led to the recovery of CD20 positivity, while V1-reconstituted cells had undetectable levels of CD20 protein. Surprisingly, CD20-directed CAR T cells were able to kill both V3- and V1-expressing cells, but the bispecific T cell engager mosunetuzumab was only effective against V3-expressing cells. To determine whether CD20 splicing is involved in immunotherapy resistance, we performed RNA-seq on four post-mosunetuzumab follicular lymphoma relapses and discovered that in two of them downregulation of CD20 was accompanied by the V3-to-V1 shift. Thus, splicing-mediated mechanisms of epitope loss extend to CD20-directed immunotherapies.
KEY POINTS
In normal & malignant human B cells, CD20 mRNA is alternatively spliced into four 5'-UTR isoforms, some of which are translation-deficient.The balance between translation-deficient and -competent isoforms modulates CD20 protein levels & responses to CD20-directed immunotherapies.
EXPLANATION OF NOVELTY
We discovered that in normal and malignant B-cells, CD20 mRNA is alternatively spliced to generate four distinct 5'-UTRs, including the longer translation-deficient V1 variant. Cells predominantly expressing V1 were still sensitive to CD20-targeting chimeric antigen receptor T-cells. However, they were resistant to the bispecific anti-CD3/CD20 antibody mosunetuzumab, and the shift to V1 were observed in CD20-negative post-mosunetuzumab relapses of follicular lymphoma.
PubMed: 37645778
DOI: 10.1101/2023.02.19.529123 -
Molecules (Basel, Switzerland) Aug 2023The aim of this study was to explore the mechanism of antitumor effect of ()-6-morpholino-9-(styrylsulfonyl)-9-purine (6-Morpholino-SPD) and...
The aim of this study was to explore the mechanism of antitumor effect of ()-6-morpholino-9-(styrylsulfonyl)-9-purine (6-Morpholino-SPD) and ()-6-amino-9-(styrylsulfonyl)-9-purine (6-Amino-SPD). The effects on apoptosis induction, mitochondrial potential, and accumulation of ROS in treated K562 cells were determined by flow cytometry. The RT-PCR method was used to measure the expression of , , , and genes, as well as selected miRNAs. Western blot analysis was used to determine the expression of Akt, cytochrome c, and caspase 3. The results demonstrate the potential of the tested derivatives as effective antitumor agents with apoptotic-inducing properties. In leukemic cells treated with 6-Amino-SPD, increased expression of and genes was observed, indicating involvement of the intrinsic mitochondrial pathway in the induction of apoptosis. Conversely, leukemic cells treated with 6-Morpholino-SPD showed reduced expression of these genes. The observed downregulation of miR-21 by 6-Morpholino-SPD may contribute to the induction of apoptosis and disruption of mitochondrial function. In addition, both derivatives exhibited increased expression of and genes, suggesting activation of the Akt/HIF pathway. However, the exact mechanism and its relations to the observed overexpression of miR-210 need further investigation. The acceptable absorption and distribution properties predicted by ADMET analysis suggest favorable pharmacokinetic properties for these derivatives.
Topics: Humans; Caspase 3; Morpholinos; Cytochromes c; Proto-Oncogene Proteins c-akt; Leukemia; MicroRNAs
PubMed: 37630388
DOI: 10.3390/molecules28166136