scholarly journals Posttranscriptional regulation of thiamin transporter-1 expression by microRNA-200a-3p in pancreatic acinar cells

2020 ◽  
Vol 319 (3) ◽  
pp. G323-G332
Author(s):  
Kalidas Ramamoorthy ◽  
Kasin Yadunandam Anandam ◽  
Tomoya Yasujima ◽  
Padmanabhan Srinivasan ◽  
Hamid M. Said
Keyword(s):  
Posttranscriptional Regulation ◽  
Vitamin B1 ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Membrane Transporter ◽  
Functional Consequences ◽  
First Time

The findings of this study show, for the first time, that the membrane transporter of vitamin B1, i.e., thiamin transporter-1 (THTR-1), is subject to regulation by microRNAs (specifically miR-200a-3p) in mouse and human primary pancreatic acinar cells (PACs). The results also show that this posttranscriptional regulation has functional consequences on the ability of PACs to take in the essential micronutrient thiamin.

scholarly journals Adaptive regulation of pancreatic acinar mitochondrial thiamin pyrophosphate uptake process: possible involvement of epigenetic mechanism(s)

2017 ◽  
Vol 313 (5) ◽  
pp. G448-G455 ◽  
Author(s):  
Subrata Sabui ◽  
Veedamali S. Subramanian ◽  
Rubina Kapadia ◽  
Hamid M. Said
Keyword(s):  
Transgenic Mice ◽  
Mammalian Cells ◽  
Acinar Cells ◽  
Epigenetic Mechanism ◽  
Pancreatic Acinar Cells ◽  
Adaptive Regulation ◽  
Oxidative Energy Metabolism ◽  
Uptake Process ◽  
First Time ◽  
Thiamin Pyrophosphate

The essentiality of thiamin stems from its roles as a cofactor [mainly in the form of thiamin pyrophosphate (TPP)] in critical metabolic reactions including oxidative energy metabolism and reduction of cellular oxidative stress. Like other mammalian cells, pancreatic acinar cells (PAC) obtain thiamin from their surroundings and convert it to TPP; mitochondria then take up TPP by a carrier-mediated process that involves the mitochondrial TPP (MTPP) transporter (MTPPT; product of SLC25A19 gene). Previous studies have characterized different physiological/biological aspects of the MTPP uptake process, but little is known about its possible adaptive regulation. We addressed this issue using pancreatic acinar 266-6 cells (PAC 266-6) maintained under thiamin-deficient (DEF) and oversupplemented (OS) conditions, as well as thiamin-DEF and -OS transgenic mice carrying the SLC25A19 promoter. We found that maintaining PAC 266-6 under the thiamin-DEF condition leads to a significant induction in mitochondrial [3H]TPP uptake, as well as in the level of expression of the MTPPT protein and mRNA compared with thiamin-OS cells. Similar findings were observed in mitochondria from thiamin-DEF mice compared with thiamin-OS. Subsequently, we demonstrated that adaptive regulation of MTTP protein was partly mediated via transcriptional mechanism(s) via studies with PAC 266-6 transfected with the SLC25A19 promoter and transgenic mice carrying the SLC25A19 promoter. This transcriptional regulation appeared to be, at least in part, mediated via epigenetic mechanism(s) involving histone modifications. These studies report, for the first time, that the PAC mitochondrial TPP uptake process is adaptively regulated by the prevailing thiamin level and that this regulation is transcriptionally mediated and involves epigenetic mechanism(s). NEW & NOTEWORTHY Our findings show, for the first time, that the mitochondrial thiamin pyrophosphate (MTPP) uptake process is adaptively regulated by the prevailing thiamin level in pancreatic acinar cells and this regulation is mediated, at least in part, by transcriptional and epigenetic mechanism(s) affecting the SLC25A19 promoter.

scholarly journals Role of MicroRNA-423-5p in posttranscriptional regulation of the intestinal riboflavin transporter-3

2017 ◽  
Vol 313 (6) ◽  
pp. G589-G598 ◽  
Author(s):  
Ram Lakhan ◽  
Veedamali S. Subramanian ◽  
Hamid M. Said
Keyword(s):  
Epithelial Cells ◽  
Posttranscriptional Regulation ◽  
Intestinal Epithelial Cells ◽  
Significant Inhibition ◽  
Luciferase Reporter ◽  
Intestinal Epithelial ◽  
Functional Consequences ◽  
Uptake Process ◽  
First Time

Riboflavin (RF) is essential for normal cellular functions and health. Humans obtain RF from exogenous sources via intestinal absorption that involves a highly specific carrier-mediated process. We have recently established that the riboflavin transporter-3 (RFVT3) is vital for the normal intestinal RF uptake process and have characterized certain aspects of its transcriptional regulation. Little is known, however, about how this transporter is regulated at the posttranscriptional level. We address this issue by focusing on the role of microRNAs. Using bioinformatics, we identified two potential interacting miRNAs with the human (h) RFVT3-3′-UTR, and showed (using pmirGLO-hRFVT3-3′-UTR) that the hRFVT3-3′-UTR is, indeed, a target for miRNA effect. Of the two putative miRNAs identified, miR-423-5p was found to be highly expressed in intestinal epithelial cells and that its mimic affected luciferase reporter activity of the pmirGLO-hRFVT3-3′-UTR construct, and also led to inhibition in RF uptake by intestinal epithelial Caco-2 and HuTu-80 cells. Furthermore, cells transfected with mutated seed sequences for miR-423-5p showed an abrogation in inhibitory effect of the miR-423-5p mimic on luciferase activity. While miR-423-5p did not affect the level of expression of the hRFVT3 mRNA, it did lead to a significant inhibition in the level of expression of its protein. Similarly, miR-423-5p was found to affect the level of expression of the mouse RFVT3 in cultured intestinal enteroids. These findings demonstrate, for the first time, that the RFVT3 is a target for posttranscriptional regulation by miRNAs in intestinal epithelial cells and that this regulation has functional consequences on intestinal RF uptake. NEW & NOTEWORTHY Our findings show for the first time that RFVT3 is a target for posttranscriptional regulation by miR-423-5p in intestinal epithelial cells, and this regulation has functional consequences on intestinal riboflavin (RF) uptake process.

scholarly journals Chronic Nicotine Exposure In Vivo and In Vitro Inhibits Vitamin B1 (Thiamin) Uptake by Pancreatic Acinar Cells

PLoS ONE ◽  
2015 ◽  
Vol 10 (12) ◽  
pp. e0143575 ◽  
Author(s):  
Padmanabhan Srinivasan ◽  
Edwin C. Thrower ◽  
Gopalakrishnan Loganathan ◽  
A. N. Balamurugan ◽  
Veedamali S. Subramanian ◽  
...  
Keyword(s):  
Vitamin B1 ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Nicotine Exposure ◽  
Chronic Nicotine ◽  
Exposure In Vivo

scholarly journals Effect of bacterial flagellin on thiamin uptake by human and mouse pancreatic acinar cells: inhibition mediated at the level of transcription of thiamin transporters 1 and 2

2019 ◽  
Vol 316 (6) ◽  
pp. G735-G743 ◽  
Author(s):  
Padmanabhan Srinivasan ◽  
Kasin Yadunandam Anandam ◽  
Vignesh Ramesh ◽  
Erica T. Geltz ◽  
Hamid M. Said
Keyword(s):  
Prolonged Exposure ◽  
Acinar Cells ◽  
Significant Inhibition ◽  
Pancreatic Acinar Cells ◽  
Vitamin B ◽  
Mrna Levels ◽  
Molecular Parameters ◽  
Atp Production ◽  
First Time

Thiamin (vitamin B1) is essential for normal cellular metabolism and function. Pancreatic acinar cells (PACs) obtain thiamin from the circulation via a specific carrier-mediated process that involves the plasma membrane thiamin transporters 1 and 2 (THTR-1 and THTR-2; products of SLC19A2 and SLC19A3 genes, respectively). There is nothing known about the effect of bacterial products/toxins on thiamin uptake by PACs. We addressed this issue in the present investigation by examining the effect of bacterial flagellin on physiological and molecular parameters of thiamin uptake by PACs. We used human primary PACs, mice in vivo, and cultured mouse-derived pancreatic acinar 266-6 cells in our investigation. The results showed that exposure of human primary PACs to flagellin led to a significant inhibition in thiamin uptake; this inhibition was associated with a significant decrease in expression of THTR-1 and -2 at the protein and mRNA levels. These findings were confirmed in mice in vivo as well as in cultured 266-6 cells. Subsequent studies showed that flagellin exposure markedly suppressed the activity of the SLC19A2 and SLC19A3 promoters and that this effect involved the Sp1 regulatory factor. Finally, knocking down Toll-like receptor 5 by use of gene-specific siRNA was found to lead to abrogation in the inhibitory effect of flagellin on PAC thiamin uptake. These results show, for the first time, that exposure of PACs to flagellin negatively impacts the physiological and molecular parameters of thiamin uptake and that this effect is mediated at the level of transcription of the SLC19A2 and SLC19A3 genes. NEW & NOTEWORTHY The present study demonstrates, for the first time, that prolonged exposure of pancreatic acinar cells to flagellin inhibits uptake of vitamin B1, a micronutrient that is essential for energy metabolism and ATP production. This effect is mediated at the level of transcription of the SLC19A2 and SLC19A3 genes and involves the Sp1 transcription factor.

scholarly journals ­­­Pro-inflammatory cytokines inhibit thiamin uptake by human and mouse pancreatic acinar cells: Involvement of transcriptional mechanism(s)

2020 ◽  
Author(s):  
Kasin Yadunandam Anandam ◽  
Padmanabhan Srinivasan ◽  
Tomoya Yasujima ◽  
Saleh Al-Juburi ◽  
Hamid M Said
Keyword(s):  
Inflammatory Cytokines ◽  
Mammalian Cells ◽  
Vitamin B1 ◽  
Acinar Cells ◽  
Inhibitory Effect ◽  
Significant Inhibition ◽  
Pancreatic Acinar Cells ◽  
Primary Mouse ◽  
Pro Inflammatory Cytokines

Thiamin (vitamin B1) plays critical roles in normal metabolism and function of all mammalian cells. Pancreatic acinar cells (PACs) import thiamin from circulation via specific carrier-mediated uptake that involves thiamin transporters-1 & -2 (THTR-1 & -2; products of SLC19A2 and SLC19A3, respectively). Our aim in this study was to investigate the effect(s) of pro-inflammatory cytokines on thiamin uptake by PACs. We used human primary (h)PACs, PAC 266-6 cells, and mice in vivo as models in the investigations. First, we examined the level of expression of THTR-1 & -2 mRNA in pancreatic tissues of patients with chronic pancreatitis and observed severe reduction in their expression compared to normal control subjects. Exposing hPACs and PAC 266-6 to pro-inflammatory cytokines (hyper IL-6, TNF-α, and IL-1β) was found to lead to a significant inhibition in thiamin uptake. Focusing on hyper-IL-6 (which also inhibited thiamin uptake by primary mouse PACs), the inhibition in thiamin uptake was found to be associated with significant reduction in THTR-1 & -2 proteins and mRNAs expression as well as in activity of the SLC19A2 and SLC19A3 promoters; it was also associated with reduction in level of expression of the transcription factor Sp1 (which is required for activity of these promoters). Finally, blocking the intracellular Stat3 signaling pathway was found to lead to a significant reversal in the inhibitory effect of hyper IL-6 on thiamin uptake by PAC 266-6. These results show that exposure of PACs to pro-inflammatory cytokines negatively impacts thiamin uptake via (at least in part) transcriptional mechanism(s).

scholarly journals Relative contribution of THTR-1 and THTR-2 in thiamin uptake by pancreatic acinar cells: studies utilizing Slc19a2 and Slc19a3 knockout mouse models

2012 ◽  
Vol 302 (5) ◽  
pp. G572-G578 ◽  
Author(s):  
Veedamali S. Subramanian ◽  
Sandeep B. Subramanya ◽  
Hamid M. Said
Keyword(s):  
Mouse Models ◽  
Knockout Mouse ◽  
Acinar Cells ◽  
Normal Function ◽  
Significant Inhibition ◽  
Pancreatic Acinar Cells ◽  
Human Pancreas ◽  
Relative Contribution ◽  
First Time ◽  
Knockout Model

Thiamin is essential for normal function of pancreatic acinar cells, and its deficiency leads to a reduction in pancreatic digestive enzymes. We have recently shown that thiamin uptake by rat pancreatic acinar cells is carrier-mediated and that both thiamin transporter (THTR)-1 and THTR-2 are expressed in these cells; little, however, is known about the relative contribution of these transporters toward total carrier-mediated thiamin uptake by these cells. We addressed this issue using a gene-specific silencing approach (siRNA) in mouse-derived pancreatic acinar 266–6 cells and Slc19a2 and Slc19a3 knockout mouse models. First we established that thiamin uptake by mouse pancreatic acinar cells is via a carrier-mediated process. We also established that these cells as well as native human pancreas express THTR-1 and THTR-2, with expression of the former (and activity of its promoter) being significantly higher than that of the latter. Using gene-specific siRNA against mouse THTR-1 and THTR-2, we observed a significant inhibition in carrier-mediated thiamin uptake by 266–6 cells in both cases. Similarly, thiamin uptake by freshly isolated primary pancreatic acinar cells of the Slc19a2 and Slc19a3 knockout mice was significantly lower than uptake by acinar cells of the respective littermates; the degree of inhibition observed in the former knockout model was greater than that of the latter. These findings demonstrate, for the first time, that both mTHTR-1 and mTHTR-2 are involved in carrier-mediated thiamin uptake by pancreatic acinar cells.

scholarly journals Thiamin uptake by pancreatic acinar cells: effect of chronic alcohol feeding/exposure

2011 ◽  
Vol 301 (5) ◽  
pp. G896-G904 ◽  
Author(s):  
Sandeep B. Subramanya ◽  
Veedamali S. Subramanian ◽  
V. Thillai Sekar ◽  
Hamid M. Said
Keyword(s):  
Acinar Cells ◽  
Normal Function ◽  
Significant Inhibition ◽  
Pancreatic Acinar Cells ◽  
Transcriptional Level ◽  
Mrna Levels ◽  
Chronic Alcohol ◽  
Metabolizing Enzymes ◽  
Uptake Process ◽  
First Time

Thiamin is important for normal function of pancreatic acinar cells, but little is known about its mechanism of uptake and about the effect of chronic alcohol use on the process. We addressed these issues using freshly isolated rat primary and rat-derived cultured AR42J pancreatic acinar cells as models. Results showed thiamin uptake by both primary and cultured AR42J pancreatic acinar cells to be via a specific carrier-mediated mechanism and that both of the thiamin transporters 1 and 2 (THTR-1 and THTR-2) are expressed in these cells. Chronic alcohol feeding of rats was found to lead to a significant inhibition of carrier-mediated thiamin uptake by pancreatic acinar cells and was associated with a significant reduction in level of expression of THTR-1 and THTR-2 at the protein and mRNA levels. Chronic exposure (96 h) of AR42J cells to alcohol also led to a significant decreased carrier-mediated thiamin uptake, an effect that was associated with a significant decrease in the activity of the human SLC19A2 and SLC19A3 promoters expressed in these cells. We also examined the effect of chronic alcohol feeding of rats on level of expression of key thiamin metabolizing enzymes (thiamin phosphokinase and thiamin pyrophosphatase) as well as on level of expression of the mitochondrial thiamin pyrophosphate transporter of pancreatic acinar cells and observed a significant inhibition in all these parameters. These results demonstrate for the first time that thiamin uptake by pancreatic acinar cells is via a carrier-mediated process and that both the THTR-1 as well as THTR-2 are expressed in these cells. Also, chronic alcohol feeding/exposure inhibits thiamin uptake process and the inhibition is, at least in part, being exerted at the transcriptional level. Furthermore, chronic alcohol feeding also negatively impacts intracellular parameters of thiamin metabolism in pancreatic acinar cells.

Visualization of CCK-evoked exocytic events in rat pancreatic acinar cells

2001 ◽  
Vol 120 (5) ◽  
pp. A24-A24
Author(s):  
H GAISANO ◽  
L TANG ◽  
L SHEU ◽  
W TRIMBLE
Keyword(s):  
Acinar Cells ◽  
Pancreatic Acinar Cells
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