The Functional Characterization Of Metal Transporter Slc39a10 In Macrophages And Slc3t9a5 In Pancreas β Cells In Mice

In the Part 1,we focused on the functional study of metal transporter Slc39a10 in macrophages.Zn as an essential trace element,plays an important role in maintaining human health.Mammalian zinc homeostasis is cooperatively regulated by two transporter protein families,10 solute-linked carrier 30,SLC30A(ZnT)exporters and 14 solute-linked carrier 39,SLC39A(Zrt-and Irt-like proteins,ZIP)importers.Previous studies have linked zinc transporters to macrophage functions.However,it remains unclear how a zinc transporter regulates the functions of macrophages.Here,we systematically quantified the expression of Slc39a and Slc30a transporters in mouse bone marrow derived macrophages(BMDMs)upon LPS stimulation.We identified that LPS significantly suppressed the expression of Slc39a10/Zip10,which is unique among all SLC39A transporters.We hypothesize that Slc39a10 may be the major zinc importer in macrophages in response to inflammatory stimuli.To test this hypothesis,we constructed and phenotypically characterized macrophage-specific SIc39a10 knockout mice(Slc39a10fl/fl;LysM-Cre+)stimulated with LPS.We found Slc39a10fl/fl,LysM-Cre+mice displayed significant survival advantage and resistance to LPS-induced endotoxic insult through stabilization of p53.These data delineate a role for Slc39a10 in regulating macrophage survival in response to LPS stimuli.We propose that Slc39a10 governs macrophage survival through regulating intracellular zinc homeostasis during inflammatory insult.In the Part2,we investigated the role of metal transporter Slc39a5 in pancreas βcells in mice.Firstly,we examined the expression levels of Slc39a family members inβ-cells isolated from diabetic mice(db/db),obesity mice(ob/ob)and high fat diet induced mice.We found that Slc39a5 significantly reduced in db/db,ob/ob and high fat diet induced mice compared to their litermate control mice respectively.To elucidate the function of Slc39a5 in pancreatic β-cells,we constructed β-cell specific Slc39a5 knockout mice.We observed aberrant glucose tolerance and glucose-stimulated insulin secretion without changes for fasting glucose and insulin sensitivity.We next tested if islet integrity or insulin storage contributes to impaired glucose tolerance in Slc39a5fl/fl,Ins2-Cre+ mice.Based on the results of our histological section staining,islets number counting and insulin content detection,there are no obvious changes.These results indicate that Slc39a5 may regulate β-cell function mainly through GSIS process,but not islet integrity or insulin storage.To explore potential mechanisms,we measured the mRNA and protein levels of key GSIS regulators.We found significant downregulation of Glut2 in Slc39a5 deficient β-cells at both mRNA and protein levels.In addition,we observed partially impaired mitochondria function in Slc39a5 deficientβ-cells.By contrast,Gck,Ucp2 and Pdxl expression levels remains unchanged.Further,we found significantly decreased zinc uptake in Slc39a5 deleted β-cells.The findings of the study suggest that Slc39a5 may serve as a novel target for diabetic disorders.