Joubert syndrome-derived induced pluripotent stem cells show altered neuronal differentiation in vitro

Joubert syndrome (JS) is a recessively inherited congenital ataxia characterized by hypotonia, psychomotor delay, abnormal ocular movements, intellectual disability, and a peculiar cerebellar and brainstem malformation, the "molar tooth sign." Over 40 causative genes have been reported, all encoding for proteins implicated in the structure or functioning of the primary cilium, a subcellular organelle widely present in embryonic and adult tissues. In this paper, we developed an in vitro neuronal differentiation model using patient-derived induced pluripotent stem cells (iPSCs), to evaluate possible neurodevelopmental defects in JS. To this end, iPSCs from four JS patients harboring mutations in distinct JS genes (AHI1, CPLANE1, TMEM67, and CC2D2A) were differentiated alongside healthy control cells to obtain mid-hindbrain precursors and cerebellar granule cells. Differentiation was monitored over 31 days through the detection of lineage-specific marker expression by qRT-PCR, immunofluorescence, and transcriptomics analysis. All JS patient-derived iPSCs, regardless of the mutant gene, showed a similar impairment to differentiate into mid-hindbrain and cerebellar granule cells when compared to healthy controls. In addition, analysis of primary cilium count and morphology showed notable ciliary defects in all differentiating JS patient-derived iPSCs compared to controls. These results confirm that patient-derived iPSCs are an accessible and relevant in vitro model to analyze cellular phenotypes connected to the presence of JS gene mutations in a neuronal context.

Structured wound angiogenesis instructs mesenchymal barrier compartments in the regenerating nerve

Organ injury stimulates the formation of new capillaries to restore blood supply raising questions about the potential contribution of neoangiogenic vessel architecture to the healing process. Using single-cell mapping, we resolved the properties of endothelial cells that organize a polarized scaffold at the repair site of lesioned peripheral nerves. Transient reactivation of an embryonic guidance program is required to orient neovessels across the wound. Manipulation of this structured angiogenic response through genetic and pharmacological targeting of Plexin-D1/VEGF pathways within an early window of repair has long-term impact on configuration of the nerve stroma. Neovessels direct nerve-resident mesenchymal cells to mold a provisionary fibrotic scar by assembling an orderly system of stable barrier compartments that channel regenerating nerve fibers and shield them from the persistently leaky vasculature. Thus, guided and balanced repair angiogenesis enables the construction of a "bridge" microenvironment conducive for axon regrowth and homeostasis of the regenerated tissue.

Lipidomic profiling in patients with heavily pretreated castration-resistant prostate cancer

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Background: Despite the advent of chemotherapy and androgen-receptor signaling inhibitors (ARSi), patients with metastatic castration-resistant prostate cancer (mCRPC) still show poor prognosis and reduced survival. The selective pressure induced by treatments favors the activation of alternative metabolic pathways that allow the persistence of cancer cells in unfavorable conditions. This study aimed at assessing the lipidomic profiles of patients with mCRPC, in order to identify lipid species potentially useful to predict for prognosis and response to therapies. Methods: Plasma samples were collected from patients with mCRPC who were starting a first-line treatment for mCRPC (1L) (n = 30) and from those who had already received at least two lines of treatment for mCRPC ( > 2L) (n = 19), including at least one ARSi and a taxane. Lipids were extracted from plasma samples using a modified Matyash method employing a mix of cold MeOH and MTBE and containing a mix of deuterated standards (Splash Lipidomix). Lipids were then analyzed with an untargeted lipidomic approach using an UHPLC Vanquish system coupled with a Q-Exactive Plus instrument. T-test was then applied to identify lipid species and classes that were differentially expressed in 1L vs < 2L patients. Results: We identified and quantified a total of 907 plasma lipids. Overall, 68 lipid species were significantly dysregulated in > 2L compared to 1L plasma samples. 56 species were found to be upregulated, whereas 12 were downregulated, with a fold change (FC) > 1.3 or < 0.75 and a p-value < 0.05. At the level of lipid classes, > 2L patients showed higher levels of acylcarnitine (CAR), diacylglycerols (DG), phosphatidylethanolamine (PE) and triacylglycerols (TG). The following lipids showed the highest FC: DG28:2 = 4.2; CAR14:0 = 3.7; CAR20:1 = 2.6; CAR18:0 = 2.3; PE40:6 = 2.3. Conversely, significantly lower levels of specific phosphatidylcholines (PC) and sterols (ST) were found in > 2L compared to 1L patients. The following species showed the lowest FC: PCO-39:3 = 0.52; ST29:1;O;S = 0.55; PC36:5 = 0.55; PC36.4 = 0.60. These results suggest that patients with strongly pretreated mCRPC show higher levels of lipid species involved in the switch between the glucose and fatty acid metabolism. We also found a dysregulation of ceramides and sphingomyelins which are well-known lipid species involved in apoptosis and cancer progression. Specific lipids warrant further investigation to be used as potential prognostic and predictive biomarkers in patients with mCRPC. Conclusions: Using a quantitative mass spectrometry approach, we investigated the dysregulation of lipids and lipid metabolism in mCRPC patients at different disease stages. We found that specific lipid species show differential levels in patients pretreated with ARSi and chemotherapy, compared to those who are naïve to these treatments, paving the way for further investigations in this field.