Functional characterization of a novel truncating mutation in Lamin A/C gene in a family with a severe cardiomyopathy with conduction defects

Gerbino, Andrea; Bottillo, Irene; Milano, Serena; Zio, Roberta De; Procino, Giuseppe; Grammatico, Paola; Svelto, María; Carmosino, Monica

doi:10.1016/j.vph.2017.12.028

Cited by 2 publications

(3 citation statements)

References 14 publications

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“…For instance, alterations in several cellular pathways, including WNT/β‐catenin, mitogen‐activated protein kinases (MAPKs) and protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signalling, have been identified in LMNA H222P/H222P mice, a mouse model of the human LMNA‐associated DCM‐CD 5,6 . Interestingly, lmna mutations may also impinge the machinery involved in Ca 2+ handling into the ER 7–9 and the connexin 43 (CX43) expression/activity at the plasma membrane in cardiomyopathies 10,11 . More recently, Salvarini et al demonstrated that the epigenetic inhibition of the sodium voltage‐gated channel alpha subunit 5 (SCN5A) in cardiomyocytes differentiated from IPS derived from patients with K219T‐LMNA pathogenic variant 12 can account for the conduction defects reported in the clinical history of these arrhythmogenic patients.…”

Section: Introductionmentioning

confidence: 99%

Pro‐inflammatory cytokines as emerging molecular determinants in cardiolaminopathies

Gerbino

Forleo

Milano

et al. 2021

J Cellular Molecular Medi

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Mutations in Lamin A/C gene ( lmna ) cause a wide spectrum of cardiolaminopathies strictly associated with significant deterioration of the electrical and contractile function of the heart. Despite the continuous flow of biomedical evidence, linking cardiac inflammation to heart remodelling in patients harbouring lmna mutations is puzzling. Therefore, we profiled 30 serum cytokines/chemokines in patients belonging to four different families carrying pathogenic lmna mutations segregating with cardiac phenotypes at different stages of severity ( n = 19) and in healthy subjects ( n = 11). Regardless lmna mutation subtype, high levels of circulating granulocyte colony‐stimulating factor (G‐CSF) and interleukin 6 (IL‐6) were found in all affected patients’ sera. In addition, elevated levels of Interleukins (IL) IL‐1Ra, IL‐1β IL‐4, IL‐5 and IL‐8 and the granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) were measured in a large subset of patients associated with more aggressive clinical manifestations. Finally, the expression of the pro‐inflammatory 70 kDa heat shock protein (Hsp70) was significantly increased in serum exosomes of patients harbouring the lmna mutation associated with the more severe phenotype. Overall, the identification of patient subsets with overactive or dysregulated myocardial inflammatory responses could represent an innovative diagnostic, prognostic and therapeutic tool against Lamin A/C cardiomyopathies.

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Section: Introductionmentioning

confidence: 99%

Pro‐inflammatory cytokines as emerging molecular determinants in cardiolaminopathies

Gerbino

Forleo

Milano

et al. 2021

J Cellular Molecular Medi

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“…Interestingly, we demonstrated that such variant mis-localized and accumulated into the ER when expressed in mature cardiomyocytes, as expected from the absence of the nuclear localization sequence (NLS), inducing ER dysfunction and the up-regulation of pro-apoptotic markers (Figure 1 and 2). Of note, a very similar truncated variant of LMNA misplaced into the ER when expressed in cardiomyocytes but induced a severe cardiomyopathy by a different pathogenic mechanism (18). These findings clearly indicate that each Lmna mutation drives cardiac detriment by its own and unique pathway and that ER stress induced by the accumulation of LMNA R321X into ER might be a useful pharmacological target in the LMNA R321X associated cardiac laminopathy.…”

Section: Discussionmentioning

confidence: 84%

“…This finding suggests that the pathogenetic mechanism of the cardiomyopathy in the nonsense mutation group might be related to either the dominant negative effect or cytotoxic effect of the resulting truncated LMNA protein rather than exclusively haploinsufficiency of LMNA wild type. Accordingly, we and others demonstrated that truncated pathogenic variants of LMNA were expressed into the heart of the carriers and may induce abnormal degradation of the WT LMNA (16) or interfere with cardiomyocytes homeostasis (17); (18); (13). Specifically, we previously characterized nonsense Lmna mutation that introduces a premature termination codon within the 6th of 12 Lmna exons corresponding to a truncated variant in the central a-helical coiled-coil rod domain (coil 2B) of the LMNA protein, R321X.…”

Section: Introductionmentioning

confidence: 99%

Targeting Unfolded Protein Response reverts ER stress and ER Ca2+ homeostasis in cardiomyocytes expressing the pathogenic variant of Lamin A/C R321X.

Pietrafesa

Zio

Scorza

et al. 2023

Preprint

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Background We previously demonstrated that an Italian family affected by a severe dilated cardiomyopathy (DCM) with history of sudden deaths at young age, carried a mutation in the Lmna gene encoding for a truncated variant of the Lamin A/C protein (LMNA), R321X. When expressed in heterologous systems, such variant accumulates into the endoplasmic reticulum (ER), inducing the activation of the PERK-CHOP pathway of the unfolded protein response (UPR), ER dysfunction and increased rate of apoptosis. The aim of this work was to analyze whether targeting the UPR can be used to revert the ER dysfunction associated with LMNA R321X expression in HL-1 cardiac cells. Methods HL-1 cardiomyocytes stably expressing R321X LMNA were used to assess the ability of 3 different drugs targeting the UPR, salubrinal, guanabenz and empagliflozin to rescue ER stress and dysfunction. In these cells, the state of activation of both the UPR and the pro-apoptotic pathway were analyzed monitoring the expression levels of phospho-PERK, phospho-eIF2a, CHOP and PARP-CL. In addition, we measured ER-dependent intracellular Ca2+ dynamics as indicator of proper ER functionality. Results We found that salubrinal and guanabenz increased the expression levels of phospho-eIF2a and downregulated the apoptosis markers CHOP and PARP-CL in R321X LMNA-cardiomyocytes, maintaining the so-called adaptive UPR. These drugs also restored ER ability to handle Ca2+ in these cardiomyocytes. Interestingly, we found that empagliflozin downregulated the apoptosis markers CHOP and PARP-CL shutting down the UPR itself through the inhibition of PERK phosphorylation in R321X LMNA-cardiomyocytes. Furthermore, upon empagliflozin treatment, ER homeostasis, in terms of ER ability to store and release intracellular Ca2+ was also restored in these cardiomyocytes. Conclusions. We provided evidence that the different drugs, although interfering with different steps of the UPR, were able to counteract pro-apoptotic processes and to preserve the ER homeostasis in R321X LMNA-cardiomyocytes. Of note, two of the tested drugs, guanabenz and empagliflozin, are already used in the clinical practice, thus providing preclinical evidence for ready-to-use therapies in patients affected by the R321X LMNA associated cardiomyocytes.

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Functional characterization of a novel truncating mutation in Lamin A/C gene in a family with a severe cardiomyopathy with conduction defects

Cited by 2 publications

References 14 publications

Pro‐inflammatory cytokines as emerging molecular determinants in cardiolaminopathies

Pro‐inflammatory cytokines as emerging molecular determinants in cardiolaminopathies

Targeting Unfolded Protein Response reverts ER stress and ER Ca2+ homeostasis in cardiomyocytes expressing the pathogenic variant of Lamin A/C R321X.

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