PIK3CA-related overgrowth spectrum (PROS) encompasses several rare conditions that lead to overgrowth of various body parts resulting from activating variants in PIK3CA. The absence of ideal cell models significantly impedes progress in PROS research. In this study, we focused on facial infiltrating lipomatosis (FIL) (A disorder within PROS) and aimed to establish and characterize an immortalized PROS cell line. Primary adipose-derived stem cells of FIL were immortal-ized through the transfection of simian virus 40 large T antigen (SV40LT). No significant mor-phological differences were observed in immortalized FIL-ADSCs (Im FIL-ADSCs). Im FIL-ADSCs expressed original mesenchymal surface markers, confirmed by flow cytometry. It harbored PIK3CA mutation and an increased level of PI3K/AKT activation, revealed by sanger sequencing and Western blot respectively. Karyotype analysis revealed a stable chromosome in Im FIL-ADSCs. Higher adipogenic potential and lower osteogenic differentiation properties were de-tected in Im FIL-ADSCs. The proliferative potential of Im FIL-ADSCs increased, whereas malig-nant transformation was not observed in the tumorigenesis assay. Moreover, RNA sequencing further elucidated the role of the transcription factor E2F1 in Im FIL-ADSCs. Drug screening unveiled that STAT3, HSP, EGFR, and NF-kB might be potential therapeutic targets for FIL. This study provided a valuable cellular resource for exploring the underlying pathogenic mechanisms and developing new targeted therapeutic options for PROS.
© 2024 Published by Elsevier B.V.

Human immunodeficiency virus (HIV) infection is currently incurable, due to the persistence of latently infected cells. The 'shock and kill' approach to a cure proposes to eliminate this reservoir via transcriptional activation of latent proviruses, enabling direct or indirect killing of infected cells. Currently available latency-reversing agents (LRAs) have however proven ineffective. To understand why, we used a novel HIV reporter strain in primary CD4+ T cells and determined which latently infected cells are reactivatable by current candidate LRAs. Remarkably, none of these agents reactivated more than 5% of cells carrying a latent provirus. Sequencing analysis of reactivatable vs. non-reactivatable populations revealed that the integration sites were distinguishable in terms of chromatin functional states. Our findings challenge the feasibility of 'shock and kill', and suggest the need to explore other strategies to control the latent HIV reservoir.
© 2018, Battivelli et al.

Cellular models and culture conditions for in vitro expansion of insulin-producing cells represent a key element to develop cell therapy for diabetes. Initial evidence that human beta-cells could be expanded after undergoing a reversible epithelial-mesenchymal transition has been recently negated by genetic lineage tracing studies in mice. Here, we report that culturing human pancreatic islets in the presence of serum resulted in the emergence of a population of nestin-positive cells. These proliferating cells were mainly C-peptide negative, although in the first week in culture, proliferating cells, insulin promoter factor-1 (Ipf-1) positive, were observed. Later passages of islet-derived cells were Ipf-1 negative and displayed a mesenchymal phenotype. These human pancreatic islet-derived mesenchymal (hPIDM) cells were expanded up to 10(14) cells and were able to differentiate toward adipocytes, osteocytes and chondrocytes, similarly to mesenchymal stem/precursor cells. Interestingly, however, under serum-free conditions, hPIDM cells lost the mesenchymal phenotype, formed islet-like clusters (ILCs) and were able to produce and secrete insulin. These data suggest that, although these cells are likely to result from preexisting mesenchymal cells rather than beta-cells, hPIDM cells represent a valuable model for further developments toward future replacement therapy in diabetes.

Dendritic cells (DCs) are potent antigen-presenting cells that express FcepsilonRI, the high-affinity IgE receptor. Although the downregulation of basophil FcepsilonRI during anti-IgE therapy with omalizumab is well documented, its effect on FcepsilonRI expression by DCs has not been reported.
We hypothesized that IgE regulates surface FcepsilonRI expression by DCs in vivo and that, consequently, anti-IgE therapy decreases FcepsilonRI expression by DCs.
In a randomized, double-blind, placebo-controlled clinical trial 24 subjects (16 receiving omalizumab and 8 receiving placebo) with seasonal allergic rhinitis received the study drug on days 0 and 28. Serial blood samples drawn on days 0, 7, 14, 28, and 42 were analyzed for precursor DC1 (pDC1) and pDC2 surface expression of FcepsilonRIalpha by using flow cytometry.
Omalizumab caused a significant decrease in surface FcepsilonRI expression at all time points examined in both the pDC1 and pDC2 subsets. No significant change was seen with placebo. The maximum decrease in FcepsilonRI expression in the omalizumab group was 52% and 83%, respectively, for the pDC1 and pDC2 subsets. The decrease in FcepsilonRI expression by both pDC subsets correlated with the decrease in serum-free IgE and was of a similar magnitude to that found in basophils. A 10-fold decrease in IgE corresponded to a 42% and 54% decrease in surface FcepsilonRI expression by the pDC1 and pDC2 subsets, respectively.
These results demonstrate that anti-IgE therapy causes a rapid decrease in DC surface FcepsilonRI expression and establish that IgE is an important regulator of FcepsilonRI expression by DCs.