Fetal and obstetrics manifestations of mitochondrial diseases.

During embryonic and neonatal development, mitochondria have essential effects on metabolic and energetic regulation, shaping cell fate decisions and leading to significant short- and long-term effects on embryonic and offspring health. Therefore, perturbation on mitochondrial function can have a pathological effect on pregnancy. Several shreds of evidence collected in preclinical models revealed that severe mitochondrial dysfunction is incompatible with life or leads to critical developmental defects, highlighting the importance of correct mitochondrial function during embryo-fetal development.

Mutant huntingtin impairs neurodevelopment in human brain organoids through CHCHD2-mediated neurometabolic failure.

Expansion of the glutamine tract (poly-Q) in the protein huntingtin (HTT) causes the neurodegenerative disorder Huntington's disease (HD). Emerging evidence suggests that mutant HTT (mHTT) disrupts brain development. To gain mechanistic insights into the neurodevelopmental impact of human mHTT, we engineered male induced pluripotent stem cells to introduce a biallelic or monoallelic mutant 70Q expansion or to remove the poly-Q tract of HTT.

Protocol for the generation of cultured cortical brain organoid slices.

Three-dimensional brain organoids from human pluripotent stem cells are a powerful tool for studying human neural networks. Here, we present a protocol for generating cortical brain organoid slices (cBOS) derived from regionalized cortical organoids and grown at the air-liquid interphase. We provide steps for slicing organoids and maintaining them in long-term culture.

mtDNA analysis using Mitopore.

Mitochondrial DNA (mtDNA) analysis is crucial for the diagnosis of mitochondrial disorders, forensic investigations, and basic research. Existing pipelines are complex, expensive, and require specialized personnel. In many cases, including the diagnosis of detrimental single nucleotide variants (SNVs), mtDNA analysis is still carried out using Sanger sequencing.

Cortical brain organoid slices (cBOS) for the study of human neural cells in minimal networks.

Brain organoids derived from human pluripotent stem cells are a promising tool for studying human neurodevelopment and related disorders. Here, we generated long-term cultures of cortical brain organoid slices (cBOS) grown at the air-liquid interphase from regionalized cortical organoids. We show that cBOS host mature neurons and astrocytes organized in complex architecture.

Balancing neuronal activity to fight neurodevelopmental disorders.

In a recent study, Rylaarsdam and colleagues revealed that mutant PACS1 gene, which causes a rare neurodevelopmental syndrome, affects the firing ability of human neurons without dysregulating the cellular architecture of brain organoids. These findings suggest aberrant neuronal electrophysiology as a possible interventional target for pediatric diseases impairing brain development.

Modeling mitochondrial DNA diseases: from base editing to pluripotent stem-cell-derived organoids.

Mitochondrial DNA (mtDNA) diseases are multi-systemic disorders caused by mutations affecting a fraction or the entirety of mtDNA copies. Currently, there are no approved therapies for the majority of mtDNA diseases. Challenges associated with engineering mtDNA have in fact hindered the study of mtDNA defects.

Generation of an induced pluripotent stem cell line from a Huntington's disease patient with a long HTT-PolyQ sequence.

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an abnormal length of CAG repeats in the gene HTT, leading to an elongated poly-glutamine (poly-Q) sequence in huntingtin (HTT). We used non-integrative Sendai virus to reprogram fibroblasts from a patient with juvenile onset HD to induced pluripotent stem cells (iPSCs). Reprogrammed iPSCs expressed pluripotency-associated markers, exhibited a normal karyotype, and following directed differentiation generated cell types belonging to the three germ layers.

Activated microglia and neuroinflammation as a pathogenic mechanism in Leigh syndrome.

Neuroinflammation is one of the main mechanisms leading to neuronal death and dysfunction in neurodegenerative diseases. The role of microglia as primary mediators of inflammation is unclear in Leigh syndrome (LS) patients. This study aims to elucidate the role of microglia in LS progression by a detailed multipronged analysis of LS neuropathology, mouse and human induced pluripotent stem cells models of Leigh syndrome.

Generation of two mother-child pairs of iPSCs from maternally inherited Leigh syndrome patients with m.8993 T > G and m.9176 T > G MT-ATP6 mutations.

We generated two pairs of mother-child iPSCs lines for Maternally Inherited Leigh Syndrome (MILS) carrying the m.8993 T > G and m.9176 T > G mutations in the MT-ATP6 gene.

Teriflunomide as a therapeutic means for myelin repair.

Background: Promotion of myelin repair in the context of demyelinating diseases such as multiple sclerosis (MS) still represents a clinical unmet need, given that this disease is not only characterized by autoimmune activities but also by impaired regeneration processes. Hence, this relates to replacement of lost oligodendrocytes and myelin sheaths-the primary targets of autoimmune attacks. Endogenous remyelination is mainly mediated via activation and differentiation of resident oligodendroglial precursor cells (OPCs), whereas its efficiency remains limited and declines with disease progression and aging.

Generation of induced pluripotent stem cells from three individuals with Huntington's disease.

Huntington's disease (HD) is a neurodegenerative disorder caused by abnormal glutamine (Q) expansion in the huntingtin protein due to elongated CAG repeats in the gene HTT. We used non-integrative episomal plasmids to generate induced pluripotent stem cells (iPSCs) from three individuals affected by HD: CH1 (58Q), and two twin brothers CH3 (44Q) and CH4 (44Q). The iPSC lines exhibited one healthy HTT allele and one with elongated CAG repeats, as confirmed by PCR and sequencing.

A Novel Gene Controls a New Structure: PiggyBac Transposable Element-Derived 1, Unique to Mammals, Controls Mammal-Specific Neuronal Paraspeckles.

Although new genes can arrive from modes other than duplication, few examples are well characterized. Given high expression in some human brain subregions and a putative link to psychological disorders [e.g.

High-content analysis of neuronal morphology in human iPSC-derived neurons.

We present a high-content analysis (HCA) protocol for monitoring the outgrowth capacity of human neurons derived from induced pluripotent stem cells (iPSCs). We describe steps to perform HCA imaging, followed by quantifying the morphology of dendrites and axons within a high-throughput system to evaluate neurons obtained through various differentiation approaches. This protocol can be used to screen for modulators of neuronal morphogenesis or neurotoxicity.

High-content screening of mitochondrial polarization in neural cells derived from human pluripotent stem cells.

We present a high-content screening (HCS) protocol for quantifying mitochondrial activity in live neural cells from human induced pluripotent stem cells (iPSCs). The assessment is based on mitochondrial membrane potential, which is influenced by the efficiency of mitochondrial bioenergetics. We describe how to perform the analysis using both an HCS platform and the open-source software CellProfiler.

Generation of four iPSC lines from four patients with Leigh syndrome carrying homoplasmic mutations m.8993T > G or m.8993T > C in the mitochondrial gene MT-ATP6.

We report the generation of four human iPSC lines (8993-A12, 8993-B12, 8993-C11, and 8993-D7) from fibroblasts of four patients affected by maternally inherited Leigh syndrome (MILS) carrying homoplasmic mutations m.8993T > G or m.8993T > C in the mitochondrial gene MT-ATP6.

A call for consensus guidelines on monitoring the integrity of nuclear and mitochondrial genomes in human pluripotent stem cells.

Despite the widespread use of human pluripotent stem cells (hPSCs), there is no general consensus with respect to monitoring the integrity of nuclear and mitochondrial genome of hPSCs. We argue that clear guidelines should be in place, and we have identified frequently asked questions that can be used to develop a practical guide for hPSCs users.

TLR4 Associated Signaling Disrupters as a New Means to Overcome HERV-W Envelope-Mediated Myelination Deficits.

Myelin repair in the adult central nervous system (CNS) is driven by successful differentiation of resident oligodendroglial precursor cells (OPCs) and thus constitutes a neurodegenerative process capable to compensate for functional deficits upon loss of oligodendrocytes and myelin sheaths as it is observed in multiple sclerosis (MS). The human endogenous retrovirus type W (HERV-W) represents an MS-specific pathogenic entity, and its envelope (ENV) protein was previously identified as a negative regulator of OPC maturation-hence, it is of relevance in the context of diminished myelin repair. We here focused on the activity of the ENV protein and investigated how it can be neutralized for improved remyelination.