To the Heart of IFs Function: Do they Aggregate on Purpose?

Background: One of the molecular hallmarks in the development of heart failure (HF) is loss of ultrastructure within the cardiac myocyte. In addition, HF is increasingly recognized as a proteinopathy characterized by the accumulation of misfolded proteins similar to Alzheimer and Parkinson disease. However, despite its increasing prevalence and poor prognosis, the advances in the pharmacological treatment of HF have been limited, highlighting an urgent need for the discovery of new therapeutic targets. We reported a consistent accumulation of mono-phosporylated desmin in experimental and clinical models of HF. We also demonstrated how mono-phosphorylated desmin is more prone to cleavage and aggregation in isolated cardiac myocytes. Therefore, if on the one hand desmin cleavage could easily explain the loss of a cardiac myocyte\u2019s ultrastructure, its high abundance and propensity to aggregate make it an ideal candidate as the seed generating pre-amyloid-oligomers (PAOs) and amyloid fibrils in the heart. Methods: Using a combination of novel and established protein biochemistry techniques, we aimed at demonstrating desmin\u2019s identity as the seed starting the nucleation process which leads to the formation of cardiac PAOs and amyloid fibrils. Results: Desmin displayed common features shared by other established PAOs and fibrils (e.g. tinctorial properties) in experimental and clinical models of HF. Conclusions: The inherent propensity of intermediate filaments to aggregate, combined with the use of cardiac tissue as a model for repeated mechanical stretch, suggest that intermediate filaments aggregation could be used as a way to dissipate/scavange mechanical as well as chemical stress. We will therefore use the highly organized structure of cardiac myocytes to infer IFs function in mammalian cells

The wide and growing range of lamin B‑related diseases: from laminopathies to cancer

B-type lamins are fundamental components of the nuclear lamina, a complex structure that acts as a scafold for organization and function of the nucleus. Lamin B1 and B2, the most represented isoforms, are encoded by LMNB1 and LMNB2 gene, respectively. All B-type lamins are synthesized as precursors and undergo sequential post-translational modifcations to generate the mature protein. B-type lamins are involved in a wide range of nuclear functions, including DNA replication and repair, regulation of chromatin and nuclear stifness. Moreover, lamins B1 and B2 regulate several cellular processes, such as tissue development, cell cycle, cellular proliferation, senescence, and DNA damage response. During embryogenesis, B-type lamins are essential for organogenesis, in particular for brain development. As expected from the numerous and pivotal functions of B-type lamins, mutations in their genes or fuctuations in their expression levels are critical for the onset of several diseases. Indeed, a growing range of human disorders have been linked to lamin B1 or B2, increasing the complexity of the group of diseases collectively known as laminopathies. This review highlights the recent fndings on the biological role of B-type lamins under physiological or pathological conditions, with a particular emphasis on brain disorders and cancer

IPMK and β-catenin take part in PLC-β1-dependent signaling pathway during myogenic differentiation

Phospholipase C (PLC)-β1 catalytic activity plays an essential role in the initiation of myogenic differentiation but the effectors involved in its signaling pathway are not well defined[1,2]. Here, we show that the overexpression of the Inositol Polyphosphate Multikinase (IPMK) promotes myogenic differentiation, and that IPMK targets the same cyclin D3 promoter region activated by PLC-β1. Moreover, cyclin D3 promoter activation relies upon c-jun binding to the promoter, both in response to PLC-β1 and to IPMK overexpression. Furthermore, both IPMK and PLC-β1 overexpression determines an increase in β-catenin translocation and accumulation to the nuclei of differentiating myoblasts resulting in higher MyoD activation. Therefore, our data show that PLC-β1, IPMK and β-catenin are mediators of the same signaling pathway that regulates cyclin D3 and myosin heavy chain (MYH) induction during myogenic differentiation

Nuclear DGKα regulates cell cycle progression in K562 cells

The existence of an independent nuclear inositide pathway distinct from the cytoplasmic one has been demonstrated in different physiological systems and in diseases (1). Phosphatidylinositols (PIs) play an important role in nuclear function regulation and behave differently from their counterparts in the cytoplasm. The autonomous nuclear PI cycle in eukaryotic cells is involved in different regulation processes, from cell proliferation to differentiation and many others (2). At nuclear level an array of kinases and phosphatases can modulate PIs. Among these, Diacylglycerol Kinases (DGKs) are a class of phosphotransferases that phosphorylate diacylglycerol (DAG) and induce the synthesis of phosphatidic acid. We Investigated DGKα localization and function in human erythroleukemia cell line K562. Synchronization experiments at different cell cycle checkpoints showed an important expression of DGKα in the nuclear fraction of this cell model, slightly peaking at G2/M. This suggested that DGKα might have a function in nuclear signaling. In particular, nuclear DGKα expression can modulate cell cycle progression, leading to changes in the phosphorylated status of the Retinoblastoma protein (pRb), thus, regulating G1/S transition: DGKα silencing or downregulation leads to impaired G1/S transition and its overexpression leads to S phase progression. The molecular mechanism by which nuclear DGKα controls pRb phosphorylation and therefore cell cycle regulation in K562 cell line are still unclear. Further studies are needed to better understand the role of DGKα in relation to other pivotal PIs involved in cell cycle regulation in the hematopoietic system

Phosphoinositide-dependent signaling in cancer: A focus on phospholipase C isozymes

Phosphoinositides (PI) form just a minor portion of the total phospholipid content in cells but are significantly involved in cancer development and progression. In several cancer types, phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] play significant roles in regulating survival, proliferation, invasion, and growth of cancer cells. Phosphoinositide-specific phospholipase C (PLC) catalyze the generation of the essential second messengers diacylglycerol (DAG) and inositol 1,4,5 trisphosphate (InsP3) by hydrolyzing PtdIns(4,5)P2. DAG and InsP3 regulate Protein Kinase C (PKC) activation and the release of calcium ions (Ca2+) into the cytosol, respectively. This event leads to the control of several important biological processes implicated in cancer. PLCs have been extensively studied in cancer but their regulatory roles in the oncogenic process are not fully understood. This review aims to provide up-to-date knowledge on the involvement of PLCs in cancer. We focus specifically on PLC\u3b2, PLC\u3b3, PLC\u3b4, and PLC\u3c9 isoforms due to the numerous evidence of their involvement in various cancer types

Nuclear Inositides and Inositide-Dependent Signaling Pathways in Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are a heterogeneous group of hematological malignancies characterized by peripheral blood cytopenia and abnormal myeloproliferation, as well as a variable risk of evolution into acute myeloid leukemia (AML). The nucleus is a highly organized organelle with several distinct domains where nuclear inositides localize to mediate essential cellular events. Nuclear inositides play a critical role in the modulation of erythropoiesis or myelopoiesis. Here, we briefly review the nuclear structure, the localization of inositides and their metabolic enzymes in subnuclear compartments, and the molecular aspects of nuclear inositides in MDS

Towards a circular project, between architecture and exhibition design. Digital platforms for reuse practices

Sustainable development and digital transition find wide space in the debate around design disciplines that take up the theme at different paces. While architectural and urban design research has long been working towards innovating design and construction paradigms in a sustainable and circular sense, exhibition design has slowly integrated these aspects into its creation and management structures. From this perspective, the digital transition represents an excellent opportunity to develop integrated systems for circular production chains. The text explores the state of arts in architecture and exhibition design, identifying innovation trajectories within cases of emblematic collaborative platforms, and highlighting their limitations and mutual lessons learned

Nuclear Phosphoinositides as Key Determinants of Nuclear Functions

Polyphosphoinositides (PPIns) are signalling messengers representing less than five per cent of the total phospholipid concentration within the cell. Despite their low concentration, these lipids are critical regulators of various cellular processes, including cell cycle, differentiation, gene transcription, apoptosis and motility. PPIns are generated by the phosphorylation of the inositol head group of phosphatidylinositol (PtdIns). Different pools of PPIns are found at distinct subcellular compartments, which are regulated by an array of kinases, phosphatases and phospholipases. Six of the seven PPIns species have been found in the nucleus, including the nuclear envelope, the nucleoplasm and the nucleolus. The identification and characterisation of PPIns interactor and effector proteins in the nucleus have led to increasing interest in the role of PPIns in nuclear signalling. However, the regulation and functions of PPIns in the nucleus are complex and are still being elucidated. This review summarises our current understanding of the localisation, biogenesis and physiological functions of the different PPIns species in the nucleus

Anatomical Laser Microdissection of the Ileum Reveals mtDNA Depletion Recovery in A Mitochondrial Neuro-Gastrointestinal Encephalomyopathy (MNGIE) Patient Receiving Liver Transplant

mitochondrial neuro-gastrointestinal encephalomyopathy (MNGIE) is a rare genetic disorder characterized by thymidine phosphorylase (TP) enzyme defect. The absence of TP activity induces the imbalance of mitochondrial nucleotide pool, leading to impaired mitochondrial DNA (mtDNA) replication and depletion. Since mtDNA is required to ensure oxidative phosphorylation, metabolically active tissues may not achieve sufficient energy production. The only effective life-saving approach in MNGIE has been the permanent replacement of TP via allogeneic hematopoietic stem cell or liver transplantation. However, the follow-up of transplanted patients showed that gut tissue changes do not revert and fatal complications, such as massive gastrointestinal bleeding, can occur. The purpose of this study was to clarify whether the reintroduction of TP after transplant can recover mtDNA copy number in a normal range. Using laser capture microdissection and droplet-digital-PCR, we assessed the mtDNA copy number in each layer of full-thickness ileal samples of a naive MNGIE cohort vs. controls and in a patient pre- and post-TP replacement. The treatment led to a significant recovery of gut tissue mtDNA amount, thus showing its efficacy. Our results indicate that a timely TP replacement is needed to maximize therapeutic success before irreversible degenerative tissue changes occur in MNGIE

Anatomical Laser Microdissection of the Ileum Reveals mtDNA Depletion Recovery in A Mitochondrial Neuro-Gastrointestinal Encephalomyopathy (MNGIE) Patient Receiving Liver Transplant

Mitochondrial neuro-gastrointestinal encephalomyopathy (MNGIE) is a rare genetic disorder characterized by thymidine phosphorylase (TP) enzyme defect. The absence of TP activity induces the imbalance of mitochondrial nucleotide pool, leading to impaired mitochondrial DNA (mtDNA) replication and depletion. Since mtDNA is required to ensure oxidative phosphorylation, metabolically active tissues may not achieve sufficient energy production. The only effective life-saving approach in MNGIE has been the permanent replacement of TP via allogeneic hematopoietic stem cell or liver transplantation. However, the follow-up of transplanted patients showed that gut tissue changes do not revert and fatal complications, such as massive gastrointestinal bleeding, can occur. The purpose of this study was to clarify whether the reintroduction of TP after transplant can recover mtDNA copy number in a normal range. Using laser capture microdissection and droplet-digital-PCR, we assessed the mtDNA copy number in each layer of full-thickness ileal samples of a naive MNGIE cohort vs. controls and in a patient pre- and post-TP replacement. The treatment led to a significant recovery of gut tissue mtDNA amount, thus showing its efficacy. Our results indicate that a timely TP replacement is needed to maximize therapeutic success before irreversible degenerative tissue changes occur in MNGIE