Mohamed Taha Moutaoufik

The Research Topic "Molecular Mechanisms and Precision Medicine in Rare Diseases" comprises six contributions that are relevant and complementary in showing the utility of molecular research for the diagnosis and understanding of diseases, as well as the application of this knowledge for the treatment of diseases that are considered rare.A common problem in rare diseases is the presence of diagnostic uncertainty due to the heterogeneity observed in the clinical case. The report by Yang et al. (Yang et al., 2025) on erythropoietic protoporphyria (EPP) is one such example, wherein the patient has an uncommon form of heme biosynthesis deficiency. In this study, Yang et al. (Yang et al., 2025) use a very detailed pathological analysis along with genome analysis to identify a splicing mutation within the FECH gene, thus resolving the uncommon case presentation in this patient.In addition to diagnosis, a detailed understanding the underlying mechanisms of the cellular and tissue-level mechanisms is critical for leveraging genetic information as a foundation for therapeutic rationale. This issue is addressed in a study by Maqoud et al. (Maqoud et al., 2025) investigating Cantύ syndrome caused by gain-of-function mutation in ATP-sensitive potassium (KATP) channels. Using a mouse model, the authors demonstrate that aberrant KATP channel activity disrupts tight junctions integrity in the colonic epithelium. These findings refine the mechanistic understanding of Cantύ syndrome and offer immportant insight into therapeutic strategies.Precision medicine in rare diseases requires the integration of molecular diagnostics with rigorous evaluation of long-term clinical outcomes. Choi et al. (Choi and Yang, 2025) contribute to this field through a cohort study examining the long-term outcome of growth hormone therapy in patients with Prader-Willi syndrome. By assessing mortality and metabolic outcome, including the risk of developing type 2 diabetes, their work addresses a critical gap in real-world evidence informing individualized therapeutic strategies.The diagnostic complexity introduced by phenocopies is further illustrated by the study of Zhao et al. (Zhao et al., 2025) on pseudohypoparathyroidism type 1B, a disorder that shares overlapping clinical and biochemical features with Gitelman syndrome. Through comprehensive biochemical and molecular analysis, the authors delineate key distinctions that differentiate hormone resistance syndromes from primary renal tubular disorders underscoring the importance of accurate diagnosis of rare endocrine disorders.Robust Disease-relevant models must be well characterized and sufficiently powerful to enable mechanistic interrogation and therapeutic development. Schiffmaier et al. (Schiffmaier et al., 2025) address this need by generating human periodontal ligament cells harboring ALPL mutations, thereby establishing patient-relevant models of hypophosphatasia models. These models faithfully tissue-specific mineralization defects and provide a valuable platform for mechanistic studies and drug screening. This approach underscores the importance of precise and disease-pecific cellular models in accelerating the process of translational research for rare skeletal and dentofacial disorders.Notably, this Research Topic broadens the scope of precision medicine beyond host genetics alone. Suryavanshi et al. (Suryavanshi et al., 2023) investigate rare microbial phylotypes across stone, urine, and stool specimens in urinary stone disease, identifying associations between microbial biomarkers and disease susceptibility. Although urinary stone disease is not classically defined as a rare genetic disorder, these findings highlight the potentially contribution of rare microbial communities to disease susceptibility and progression.The six articles included in this research topic converge on several key overarching messages. First, integrated molecular diagnostics grounded in genetics, biochemistry, and pathology are critical cornerstone for the accurate diagnosing of rare diseases. Second, mechanistic basic research based using cellular and tissue-based models is central in harnessing genetic variability and translate it into rational therapeutic strategy. Third, precision therapies often rely on longitudinal follow-up to rigorously evaluate treatment efficacy and safety within well-defined genetic populations. Finally, precision medicine approaches increasingly benefit from the integration of multi-omics strategies, such as microbiome profiling, to gain deeper insights into disease pathology.In conclusion, this Research Topic demonstrates that methodological rigor, mechanistic insights, and translational relevance can be seamlessly integrated to advance precision medicine in rare diseases. By linking diagnostic innovation with disease mechanisms and clinical outcomes, this collection of articles outlines a clear path forward towards improved accuracy and the development on individualized therapeutic strategies to better serve patients with rare diseases.

Mitochondrial dysfunction is a hallmark of Parkinson’s disease (PD), but the mechanisms by which it drives autosomal dominant and idiopathic forms of PD remain unclear. To investigate this, we generated and performed a comprehensive phenotypic analysis of a knock-in mouse model carrying the T61I mutation in the mitochondrial protein CHCHD2 (coiled-coil–helix–coiled-coil–helix domain–containing 2), which causes late-onset symptoms indistinguishable from idiopathic PD. We observed pronounced mitochondrial disruption in substantia nigra dopaminergic neurons, including distorted ultrastructure and CHCHD2 aggregation, as well as disrupted mitochondrial protein-protein interactions in brain lysates. These abnormalities were associated with a whole-body metabolic shift toward glycolysis, elevated mitochondrial reactive oxygen species (ROS), and progressive accumulation of aggregated α-synuclein. In idiopathic PD, CHCHD2 gene expression also correlated with α-synuclein levels in vulnerable dopaminergic neurons, and CHCHD2 protein accumulated in early Lewy aggregates. These findings delineate a pathogenic cascade in which CHCHD2 accumulation impairs mitochondrial respiration and increases ROS production, driving α-synuclein aggregation and neurodegeneration.

Glutamate receptors represent a potential target for neuroprotection in neurodegenerative neurological conditions. Perampanel, a non-competitive α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor (AMPAR) antagonist, is clinically approved for the management of epilepsy. Perampanel’s neuroprotective effects have been reported in global and focal cerebral ischemia models, but the cellular mechanisms remain incompletely understood. Therefore, we studied the potential neuroprotective effects of perampanel in rats using the pial vessel disruption (PVD) stroke model, an established focal cortical non-reperfusion ischemic stroke model. Perampanel was given once intraperitoneally (3 mg/kg body weight) 1 h after PVD surgery and repeated on days 2–3 post-surgery. On the fourth day post PVD, animal behavioral assays and imaging, biochemical, and electrophysiological analyses were performed. Compared to vehicle control, perampanel in PVD-treated rats significantly inhibited hippocampal neurodegeneration and long-term potentiation deficits. Perampanel also attenuated PVD-induced motor deficits, depressive/anxiety-like behaviors, and hippocampal-dependent cognitive impairment. In addition, perampanel prevented the PVD-induced downregulation of surface-expressed GluA1 and GluA2 AMPARs and increased phosphorylation of GluA1 at S831 and S845. Molecular docking analysis revealed perampanel binding to transmembrane regions M1, M3 and M4 of GluA1 and GluA2 subunits. Together, our results show that perampanel attenuated PVD-induced neurodegeneration and behavioral deficits by blocking AMPARs and decreasing GluA1 and GluA2 internalization. In addition, this study shows the neuroprotective potential of perampanel through the inhibition of neuroinflammation mediated by activated microglia and astrocytes following cerebral ischemia. This study is the first to evaluate perampanel in the pial vessel disruption model of ischemia without reperfusion, a clinically relevant stroke paradigm that differs fundamentally from middle cerebral carotid artery occlusion and photothrombosis stroke models.

Glutamate receptors represent a potential target for neuroprotection in neurodegener-ative neurological conditions. Perampanel, a non-competitive α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor (AMPAR) antagonist, is clinically approved for the management of epilepsy. Perampanel’s neuroprotective ef-fects have been reported in global and focal cerebral ischemia models, but the cellular mechanisms remain incompletely understood. Here we investigated the potential neuroprotective effects of perampanel in rats subjected to pial vessel disruption (PVD), which mimics a focal cortical non-reperfusion ischemic stroke model. Perampanel was given intraperitoneally (3mg/kg body weight) 1 hr after PVD surgery and once daily for two days post-surgery. On the fourth day post PVD, animal behavioral assays and imaging, biochemical and electrophysiological analyses were performed. Compared to vehicle control, perampanel in PVD-treated rats significantly inhibited hippocampal neurodegeneration and long-term potentiation deficits. Perampanel also attenuated PVD-induced motor deficits, depressive/anxiety-like behaviors, and hippocam-pal-dependent cognitive impairment. In addition, perampanel prevented the PVD-induced downregulation of surface-expressed GluA1 and GluA2 AMPARs and increased phosphorylation of GluA1 at S831 and S845. Molecular docking analysis revealed perampanel binding to transmembrane regions M1, M3 and M4 of GluA1 and GluA2 subunits. Together, our results show that perampanel attenuated PVD-induced neurodegeneration and behavioral deficits by blocking AMPARs and decreasing GluA1 and GluA2 internalization. In addition, this study shows the neuroprotective potential of perampanel through the inhibition of neuroinflammation mediated by ac-tivated microglia and astrocytes following cerebral ischemia.

Mutations in the mitochondrial cristae protein CHCHD2 lead to a late-onset autosomal dominant form of Parkinson’s disease (PD) which closely resembles idiopathic PD, providing the opportunity to gain new insights into the mechanisms of mitochondrial dysfunction contributing to PD. To begin to address this, we used CRISPR genome-editing to generate CHCHD2 T61I point mutant mice. CHCHD2 T61I mice had normal viability, and had only subtle motor deficits with no signs of premature dopaminergic (DA) neuron degeneration. Nonetheless, CHCHD2 T61I mice exhibited robust molecular changes in the brain including increased CHCHD2 insolubility, accumulation of CHCHD2 protein preferentially in the substantia nigra (SN), and elevated levels of α-synuclein. Metabolic analyses revealed an increase in glucose metabolism through glycolysis relative to the TCA cycle with increased respiratory exchange ratio, and immune-electron microscopy revelated disrupted mitochondria in DA neurons. Moreover, spatial genomics revealed decreased expression of mitochondrial complex I and III respiratory chain proteins, while proteomics revealed increased respiratory chain and other mitochondrial protein-protein interactions. As such, the CHCHD2 T61I point-mutation mice exhibit robust mitochondrial disruption and a consequent metabolic shift towards glycolysis. These findings thus establish CHCHD2 T61I mice as a new model for mitochondrial-based PD, and implicate disrupted respiratory chain function as a likely causative driver.

We previously found that chronic adenosine A1 receptor stimulation with N⁶-Cyclopentyladenosine increased α-synuclein misfolding and neurodegeneration in a novel α-synucleinopathy model, a hallmark of Parkinson’s disease. Here, we aimed to synthesize a dimer caffeine-indan linked by a 6-carbon chain to cross the blood–brain barrier and tested its ability to bind α-synuclein, reducing misfolding, behavioral abnormalities, and neurodegeneration in our rodent model. Behavioral tests and histological stains assessed neuroprotective effects of the dimer compound. A rapid synthesis of the ¹⁸F-labeled analogue enabled Positron Emission Tomography and Computed Tomography imaging for biodistribution measurement. Molecular docking analysis showed that the dimer binds to α-synuclein N- and C-termini and the non-amyloid-β-component (NAC) domain, similar to 1-aminoindan, and this binding promotes a neuroprotective α-synuclein “loop” conformation. The dimer also binds to the orthosteric binding site for adenosine within the adenosine A1 receptor. Immunohistochemistry and confocal imaging showed the dimer abolished α-synuclein upregulation and aggregation in the substantia nigra and hippocampus, and the dimer mitigated cognitive deficits, anxiety, despair, and motor abnormalities. The ¹⁸F-labeled dimer remained stable post-injection and distributed in various organs, notably in the brain, suggesting its potential as a Positron Emission Tomography tracer for α-synuclein and adenosine A1 receptor in Parkinson’s disease therapy.

We previously found that chronic adenosine A1 receptor stimulation with N6-Cyclopentyladenosine increased α-synuclein misfolding and neurodegeneration in a novel α-synucleinopathy model, a hallmark of Parkinson’s disease. Here, we aimed to synthesize a dimer caffeine-indan linked by a 6-carbon chain to cross the blood-brain barrier and tested its ability to bind α-synuclein, reducing misfolding, behavioural abnormalities, and neurodegeneration in our rodent model. Behavioural tests and histological stains assessed neuroprotective effects of the dimer compound. A rapid synthesis of the 18F-labelled analogue enabled Positron Emission Tomography and Computed Tomography imaging for biodistribution measurement. Molecular docking analysis showed that the dimer binds to α-synuclein N- and C-termini and the non-amyloid-β-component (NAC) domain, similar to 1-aminoindan, and this binding promotes a neuroprotective α-synuclein “loop” conformation. The dimer also binds to the orthosteric binding site for adenosine within the adenosine A1 receptor. Immunohistochemistry and confocal imaging showed the dimer abolished α-synuclein upregulation and aggregation in the substantia nigra and hippocampus, and the dimer mitigated cognitive deficits, anxiety, despair, and motor abnormalities. The 18F-labelled dimer remained stable post-injection and distributed in various organs, notably in the brain, suggesting its potential as a Positron Emission Tomography tracer for α-synuclein and adenosine A1 receptor in Parkinson’s disease therapy.

Mitochondria possess their own DNA (mtDNA) and are capable of carrying out their transcription and translation. Although protein synthesis can take place in mitochondria, the majority of the proteins in mitochondria have nuclear origin. 3′ and 5′ untranslated regions of mRNAs (3′-UTR and 5′-UTR, respectively) are thought to play key roles in directing and regulating the activity of mitochondria mRNAs. Here we investigate the association between the presence of 3′-UTR from OXA1 gene on a prokaryotic reporter mRNA and mitochondrial translation in yeast. OXA1 is a nuclear gene that codes for mitochondrial inner membrane insertion protein and its 3′-UTR is shown to direct its mRNA toward mitochondria. It is not clear, however, if this mRNA may also be translated by mitochondria. In the current study, using a β-galactosidase reporter gene, we provide genetic evidence for a correlation between the presence of 3′-UTR of OXA1 on an mRNA and mitochondrial translation in yeast.

The coronavirus disease 19 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) prompted the development of diagnostic and therapeutic frameworks for timely containment of this pandemic. Here, we utilized our non-conventional computational algorithm, InSiPS, to rapidly design and experimentally validate peptides that bind to SARS-CoV-2 spike (S) surface protein. We previously showed that this method can be used to develop peptides against yeast proteins, however, the applicability of this method to design peptides against other proteins has not been investigated. In the current study, we demonstrate that two sets of peptides developed using InSiPS method can detect purified SARS-CoV-2 S protein via ELISA and Surface Plasmon Resonance (SPR) approaches, suggesting the utility of our strategy in real time COVID-19 diagnostics. Mass spectrometry-based salivary peptidomics shortlist top SARS-CoV-2 peptides detected in COVID-19 patients’ saliva, rendering them attractive SARS-CoV-2 diagnostic targets that, when subjected to our computational platform, can streamline the development of potent peptide diagnostics of SARS-CoV-2 variants of concern. Our approach can be rapidly implicated in diagnosing other communicable diseases of immediate threat.

Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a chloride and bicarbonate channel in secretory epithelia with a critical role in maintaining fluid homeostasis. Mutations in CFTR are associated with Cystic Fibrosis (CF), the most common lethal autosomal recessive disorder in Caucasians. While remarkable treatment advances have been made recently in the form of modulator drugs directly rescuing CFTR dysfunction, there is still considerable scope for improvement of therapeutic effectiveness. Here, we report the application of a high‐throughput screening variant of the Mammalian Membrane Two‐Hybrid (MaMTH‐HTS) to map the protein–protein interactions of wild‐type (wt) and mutant CFTR (F508del), in an effort to better understand CF cellular effects and identify new drug targets for patient‐specific treatments. Combined with functional validation in multiple disease models, we have uncovered candidate proteins with potential roles in CFTR function/CF pathophysiology, including Fibrinogen Like 2 (FGL2), which we demonstrate in patient‐derived intestinal organoids has a significant effect on CFTR functional expression.