Dehydrated hereditary stomatocytosis (DHS), or xerocytosis, is an autosomal dominant hemolytic anemia. Most patients with DHS carry mutations in the PIEZO1 gene encoding a mechanosensitive cation channel. We here demonstrate that patients with DHS have low levels of hepcidin and only a slight increase of ERFE, the erythroid negative regulator of hepcidin. We demonstrated that at the physiological level, PIEZO1 activation induced Ca2+ influx and suppression of HAMP expression in primary hepatocytes. In two hepatic cellular models expressing PIEZO1 WT and two PIEZO1 gain-of-function mutants (R2456H and R2488Q), we highlight altered expression of a few genes/proteins involved in iron metabolism. Mutant cells showed increased intracellular Ca2+ compared to WT, which was correlated to increased phosphorylation of ERK1/2, inhibition of the BMP-SMADs pathway, and suppression of HAMP transcription. Moreover, the HuH7 cells, treated with PD0325901, a potent inhibitor of ERK1/2 phosphorylation, reduced the phosphorylation of ERK1/2 with the consequent increased phosphorylation of SMAD1/5/8, confirming the link between the two pathways. Another “proof of concept” for the mechanism that links PIEZO1 to HAMP regulation was obtained by mimicking PIEZO1 activation by cell Ca2+ overload, by the Ca2+ ionophore A23187. There was strong down-regulation of HAMP gene expression after this Ca2+ overload. Finally, the inhibition of PIEZO1 by GsMTx4 leads to phenotype rescue. This is the first demonstration of a direct link between PIEZO1 and iron metabolism, which defines the channel as a new hepatic iron metabolism regulator and as a possible therapeutic target of iron overload in DHS and other iron-loading anemias.

Gain-of-function mutations in PIEZO1 directly impair hepatic iron metabolism via the inhibition of the BMP/SMADs pathway / Andolfo, I.; Rosato, B. E.; Manna, F.; De Rosa, G.; Marra, R.; Gambale, A.; Girelli, D.; Russo, R.; Iolascon, A.. - In: AMERICAN JOURNAL OF HEMATOLOGY. - ISSN 0361-8609. - 95:2(2020), pp. 188-197. [10.1002/ajh.25683]

Gain-of-function mutations in PIEZO1 directly impair hepatic iron metabolism via the inhibition of the BMP/SMADs pathway

Andolfo I.
Primo
Conceptualization
;
Rosato B. E.;Manna F.;De Rosa G.;Marra R.;Gambale A.;Russo R.
;
Iolascon A.
2020

Abstract

Dehydrated hereditary stomatocytosis (DHS), or xerocytosis, is an autosomal dominant hemolytic anemia. Most patients with DHS carry mutations in the PIEZO1 gene encoding a mechanosensitive cation channel. We here demonstrate that patients with DHS have low levels of hepcidin and only a slight increase of ERFE, the erythroid negative regulator of hepcidin. We demonstrated that at the physiological level, PIEZO1 activation induced Ca2+ influx and suppression of HAMP expression in primary hepatocytes. In two hepatic cellular models expressing PIEZO1 WT and two PIEZO1 gain-of-function mutants (R2456H and R2488Q), we highlight altered expression of a few genes/proteins involved in iron metabolism. Mutant cells showed increased intracellular Ca2+ compared to WT, which was correlated to increased phosphorylation of ERK1/2, inhibition of the BMP-SMADs pathway, and suppression of HAMP transcription. Moreover, the HuH7 cells, treated with PD0325901, a potent inhibitor of ERK1/2 phosphorylation, reduced the phosphorylation of ERK1/2 with the consequent increased phosphorylation of SMAD1/5/8, confirming the link between the two pathways. Another “proof of concept” for the mechanism that links PIEZO1 to HAMP regulation was obtained by mimicking PIEZO1 activation by cell Ca2+ overload, by the Ca2+ ionophore A23187. There was strong down-regulation of HAMP gene expression after this Ca2+ overload. Finally, the inhibition of PIEZO1 by GsMTx4 leads to phenotype rescue. This is the first demonstration of a direct link between PIEZO1 and iron metabolism, which defines the channel as a new hepatic iron metabolism regulator and as a possible therapeutic target of iron overload in DHS and other iron-loading anemias.
2020
Gain-of-function mutations in PIEZO1 directly impair hepatic iron metabolism via the inhibition of the BMP/SMADs pathway / Andolfo, I.; Rosato, B. E.; Manna, F.; De Rosa, G.; Marra, R.; Gambale, A.; Girelli, D.; Russo, R.; Iolascon, A.. - In: AMERICAN JOURNAL OF HEMATOLOGY. - ISSN 0361-8609. - 95:2(2020), pp. 188-197. [10.1002/ajh.25683]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/828922
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