A comprehensive phenotypic characterization of a whole-body Wdr45 knock-out mouse.

Pathogenic variants in the WDR45 (OMIM: 300,526) gene on chromosome Xp11 are the genetic cause of a rare neurological disorder characterized by increased iron deposition in the basal ganglia. As WDR45 encodes a beta-propeller scaffold protein with a putative role in autophagy, the disease has been named Beta-Propeller Protein-Associated Neurodegeneration (BPAN). BPAN represents one of the four most common forms of Neurodegeneration with Brain Iron Accumulation (NBIA). In the current study, we generated and characterized a whole-body Wdr45 knock-out (KO) mouse model. The model, developed using TALENs, presents a 20-bp deletion in exon 2 of Wdr45. Homozygous females and hemizygous males are viable, proving that systemic depletion of Wdr45 does not impair viability and male fertility in mice. The in-depth phenotypic characterization of the mouse model revealed neuropathology signs at four months of age, neurodegeneration progressing with ageing, hearing and visual impairment, specific haematological alterations, but no brain iron accumulation. Biochemically, Wdr45 KO mice presented with decreased complex I (CI) activity in the brain, suggesting that mitochondrial dysfunction accompanies Wdr45 deficiency. Overall, the systemic Wdr45 KO described here complements the two mouse models previously reported in the literature (PMIDs: 26,000,824, 31,204,559) and represents an additional robust model to investigate the pathophysiology of BPAN and to test therapeutic strategies for the disease.

Generation of two human iPSC lines, HMGUi004-A and FINCBi004-A, from fibroblasts of MPAN patients carrying pathogenic recessive mutations in the gene C19orf12.

Mitochondrial membrane Protein-Associated Neurodegeneration (MPAN) is a lethal neurodegenerative disorder caused by mutations in the human gene C19orf12. The molecular mechanisms underlying the disorder are still unclear, and no established therapy is available. Here, we describe the generation and characterization of two human induced pluripotent stem cell (iPSC) lines derived from skin fibroblasts of two MPAN patients carrying homozygous recessive mutations in C19orf12. These iPSC lines represent a useful resource for future investigations on the pathology of MPAN, as well as for the development of successful treatments.

Identification of Autophagy as a Functional Target Suitable for the Pharmacological Treatment of Mitochondrial Membrane Protein-Associated Neurodegeneration (MPAN) In Vitro.

Mitochondrial membrane protein-associated neurodegeneration (MPAN) is a relentlessly progressive neurodegenerative disorder caused by mutations in the C19orf12 gene. C19orf12 has been implicated in playing a role in lipid metabolism, mitochondrial function, and autophagy, however, the precise functions remain unknown. To identify new robust cellular targets for small compound treatments, we evaluated reported mitochondrial function alterations, cellular signaling, and autophagy in a large cohort of MPAN patients and control fibroblasts. We found no consistent alteration of mitochondrial functions or cellular signaling messengers in MPAN fibroblasts. In contrast, we found that autophagy initiation is consistently impaired in MPAN fibroblasts and show that C19orf12 expression correlates with the amount of LC3 puncta, an autophagy marker. Finally, we screened 14 different autophagy modulators to test which can restore this autophagy defect. Amongst these compounds, carbamazepine, ABT-737, LY294002, oridonin, and paroxetine could restore LC3 puncta in the MPAN fibroblasts, identifying them as novel potential therapeutic compounds to treat MPAN. In summary, our study confirms a role for C19orf12 in autophagy, proposes LC3 puncta as a functionally robust and consistent readout for testing compounds, and pinpoints potential therapeutic compounds for MPAN.

Generation of two human iPSC lines, HMGUi003-A and MRIi028-A, carrying pathogenic biallelic variants in the PPCS gene.

Phosphopantothenoylcysteine synthetase (PPCS) catalyzes the second step of the de novo coenzyme A (CoA) synthesis starting from pantothenate. Mutations in PPCS cause autosomal-recessive dilated cardiomyopathy, often fatal, without apparent neurodegeneration, whereas pathogenic variants in PANK2 and COASY, two other genes involved in the CoA synthesis, cause Neurodegeneration with Brain Iron Accumulation (NBIA). PPCS-deficiency is a relatively new disease with unclear pathogenesis and no targeted therapy. Here, we report the generation of induced pluripotent stem cells from fibroblasts of two PPCS-deficient patients. These cellular models could represent a platform for pathophysiological studies and testing of therapeutic compounds for PPCS-deficiency.

The secretome of skin cancer cells activates the mTOR/MYC pathway in healthy keratinocytes and induces tumorigenic properties.

Cutaneous squamous cell carcinoma (cSCC) is the most prominent tumor of non-melanoma skin cancers and the most aggressive tumor among keratinocyte carcinoma of the skin, showing a high potential for local invasion and metastasis. The cSCC incidences increased dramatically in recent years and the disease occurs more commonly than any other malignancy. The secretome of cancer cells is currently the focus of many studies in order to identify new marker proteins for different types of cancer and to investigate its influence on the tumor microenvironment. In our study we evaluated whether the secretome of cSCC cells has an impact on keratinocytes, the surrounding tissue cells of cSCC. Therefore, we analyzed and compared the secretome of human A431 cancer cells and of HaCaT keratinocytes by mass spectrometry. In a second experiment, keratinocytes were exposed to the secretome of A431 cells and vice versa and the transcriptome was analyzed by next-generation sequencing. HaCaT cells incubated with A431 conditioned medium revealed a significantly activated mammalian target of rapamycin pathway with a concomitant increase in proliferation and migration. In conclusion, our data demonstrate the impact of the secretome of cancer cells on the transcription machinery of the cells surrounding the tumor, leading to a tumorigenic cell fate.