Biology subjects

Ghidelli-Disse, S.

Publications and source records attributed to Ghidelli-Disse, S..

5 recordsLinked to original sources

bioRxiv2026

NLRX1 is an essential, druggable regulator of mitochondrial permeability transition

The molecular composition of the mitochondrial permeability transition pore (mPTP) remains contested, and several efficacious mPTP inhibitors act through undefined, cyclophilin D (CypD)-independent targets. Using two structurally distinct chemotypes of optimised, brain-penetrant mPTP inhibitors as chemical probes, we applied affinity-based chemoproteomics to identify the mitochondrial NOD-like receptor NLRX1 as their shared target. Both chemotypes bind NLRX1, and binding potency across a compound series tracks mPTP-inhibitory activity. Using CRISPR-Cas9-edited human cells and Nlrx1-/- mouse tissues, we show that NLRX1 is required for normal calcium-induced mPTP opening: its loss raises the calcium threshold for pore opening and its overexpression lowers it, independently of CypD. NLRX1 associates with postulated mPTP components, including ATP synthase and the adenine nucleotide translocase, in a compound-sensitive manner, and sustains mitochondrial protein homeostasis over longer timescales. The lead compound, GSK900, is orally bioavailable, brain-penetrant, and active in an mPTP-sensitive neurological injury model. These findings, converging with recent genetic studies, establish NLRX1 as an essential, CypD-independent regulator of mitochondrial permeability transition and provide brain-penetrant chemical tools to interrogate this biology.

cell biology↗

bioRxiv2025

The Human Chk1 Inhibitor CHIR-124 Shows Multistage Activity Against Plasmodium falciparum via Dual Inhibition of PfArk1 and Hemozoin Formation

The high burden of malaria and growing resistance to frontline antimalarials demand new drug target combinations with reduced propensities for conferring parasite resistance. An attractive approach for circumventing antimalarial drug resistance is target repurposing in which known drugs that act through protein targets of human origin that are also active against the human malaria parasite Plasmodium falciparum are exploited to identify novel antimalarial drug targets. Here we show that the human checkpoint kinase 1 (Chk1) inhibitor CHIR-124 is active in vitro against both drug-sensitive and drug-resistant asexual blood stage parasites and competitively binds to several Plasmodium kinases. The compound also shows moderate activity against both the liver and gametocyte forms of the parasite. Further target investigation of CHIR-124 via conditional knockdown experiments confirmed that P. falciparum Aurora-related kinase 1 (PfArk1) is implicated in its parasiticidal activity. Notably, CHIR-124 also inhibits {beta}-hematin (synthetic hemozoin) formation and causes a dose-dependent increase in free heme that correlates with inhibition of parasite growth. These findings suggest that polypharmacology is involved in the activity of CHIR-124 against P. falciparum via the dual inhibition of Plasmodium PfArk1 and hemozoin formation, both essential for parasite proliferation. This is further supported by in vitro drug combination experiments, morphological studies and resistance generation attempts. This study validates the feasibility of dual Plasmodium kinase/hemozoin formation inhibitors active against resistant strains with decreased resistance risks in the fight against malaria.

microbiology↗

bioRxiv2025

Targeting Aurora kinases as essential cell cycle regulators to deliver multi-stage antimalarials against Plasmodium falciparum

Kinases that play critical roles in the development and adaptation of Plasmodium falciparum present novel opportunities for chemotherapeutic intervention. Of particular interest are mitotic kinases that regulate the proliferation of the parasites by controlling nuclear division, segregation and cytokinesis. We evaluated the potential of human Aurora kinase (Aur) inhibitors to inhibit P. falciparum development by targeting members of the Aurora-related kinase (Ark) family in this parasite. Several human AurB inhibitors exhibited multistage potency (<250 nM) against all proliferative stages of parasite development, including asexual blood stages, liver schizonts and male gametes. Among the most potent compounds, hesperadin and AT83 exhibit >1000x selectivity towards the parasite without concerns about mammalian cell toxicity. Importantly, we identified PfArk1 as the principal vulnerable Ark family member, with specific inhibition of PfArk1 as the primary target for hesperadin and the human anaplastic lymphoma kinase (ALK) inhibitor TAE684. Hesperadins whole-cell and protein activity validates it as a unique PfArk1 tool compound. Inhibition of PfArk1 results in the parasites inability to complete mitotic processes, presenting with unsegregated, multi-lobed nuclei caused by aberrant microtubule organization. This suggests that PfArk1 is the main Aur mitotic kinase in proliferative stages of Plasmodium, characterized by bifunctional AurA and B activity. This paves the way for drug discovery campaigns based on hesperadin targeting PfArk1.

molecular biology↗

bioRxiv2021

Patient-derived gene and protein expression signatures of NGLY1 deficiency

N-Glycanase 1 (NGLY1) deficiency is a rare and complex genetic disorder. Although recent studies have shed light on the molecular underpinnings of NGLY1 deficiency, a systematic characterization of gene and protein expression changes in patient-derived cells has been lacking. Here, we performed RNA-sequencing and mass spectrometry to determine the transcriptomes and proteomes of 66 cell lines representing 4 different cell types derived from 14 NGLY1 deficient patients and 17 controls. While gene and protein expression levels agreed well with each other, expression differences were more pronounced at the protein level. Although NGLY1 protein levels were up to 9.5-fold downregulated in patients compared to parent controls, depending on the genotype, NGLY1 protein was still detectable in all patient-derived lymphoblastoid cell lines. Consistent with the role of NGLY1 as a regulator of the transcription factor Nrf1, we observed a cell type-independent downregulation of proteasomal genes in NGLY1 deficient cells. In contrast, genes involved in ribosomal mRNA processing were upregulated in multiple cell types. In addition, we observed cell type-specific effects. For example, genes and proteins involved in glutathione synthesis, such as the glutamate-cystein ligase subunits GCLC and GCLM, were downregulated specifically in lymphoblastoid cells. We provide a web application that enables access to all results generated in this study at https://apps.embl.de/ngly1browser. This resource will guide future studies of NGLY1 deficiency in directions that are most relevant to patients.

systems biology↗

bioRxiv2020

A multipass membrane protein interacts with the cGMP-dependent protein kinase to regulate critical calcium signals in malaria parasites

In malaria parasites, all cGMP-dependent signalling is mediated through a single cGMP-dependent protein kinase (PKG), a major function of which is to control essential calcium signals. However, how PKG transmits these signals in the absence of known second messenger-dependent calcium channels or scaffolding proteins is unknown. Here we identify a polytopic membrane protein, ICM1, with homology to transporters and calcium channels that is tightly-associated with PKG in both Plasmodium falciparum asexual blood stages and P. berghei gametocytes. Phosphoproteomic analyses in both Plasmodium species reveal multiple ICM1 phosphorylation events dependent upon PKG activity. Stage-specific depletion of P. berghei ICM1 blocks gametogenesis due to the inability of mutant parasites to mobilise intracellular calcium upon PKG activation, whilst conditional loss of P. falciparum ICM1 results in reduced calcium mobilisation, defective egress and lack of invasion. Our findings provide new insights into atypical calcium homeostasis in malaria parasites essential for pathology and disease transmission.

microbiology↗