The High Mobility Group A1 (HMGA1) Chromatin Architectural Factor Modulates Nuclear Stiffness in Breast Cancer Cells

13siPlasticity is an essential condition for cancer cells to invade surrounding tissues. The nucleus is the most rigid cellular organelle and it undergoes substantial deformations to get through environmental constrictions. Nuclear stiffness mostly depends on the nuclear lamina and chromatin, which in turn might be affected by nuclear architectural proteins. Among these is the HMGA1 (High Mobility Group A1) protein, a factor that plays a causal role in neoplastic transformation and that is able to disentangle heterochromatic domains by H1 displacement. Here we made use of atomic force microscopy to analyze the stiffness of breast cancer cellular models in which we modulated HMGA1 expression to investigate its role in regulating nuclear plasticity. Since histone H1 is the main modulator of chromatin structure and HMGA1 is a well-established histone H1 competitor, we correlated HMGA1 expression and cellular stiffness with histone H1 expression level, post-translational modifications, and nuclear distribution. Our results showed that HMGA1 expression level correlates with nuclear stiffness, is associated to histone H1 phosphorylation status, and alters both histone H1 chromatin distribution and expression. These data suggest that HMGA1 might promote chromatin relaxation through a histone H1-mediated mechanism strongly impacting on the invasiveness of cancer cells-openopenSenigagliesi B, Penzo C, Severino LU, Maraspini R, Petrosino S, Morales-Navarrete H, Pobega E, Ambrosetti E, Parisse P, Pegoraro S, Manfioletti G, Casalis L, Sgarra RSenigagliesi, Beatrice; Penzo, C; Severino, Lu; Maraspini, R; Petrosino, Sara; Morales-Navarrete, H; Pobega, E; Ambrosetti, E; Parisse, P; Pegoraro, S; Manfioletti, G; Casalis, L; Sgarra,

TDP-43 real-Time quaking induced conversion reaction optimization and detection of seeding activity in CSF of amyotrophic lateral sclerosis and frontotemporal dementia patients

The pathological deposition of the transactive response DNA-binding protein of 43 kDa occurs in the majority (∼97%) of amyotrophic lateral sclerosis and in around 45% of frontotemporal lobar degeneration cases. Amyotrophic lateral sclerosis and frontotemporal lobar degeneration clinically overlap, presenting a continuum of phenotypes. Both amyotrophic lateral sclerosis and frontotemporal lobar degeneration lack treatments capable of interfering with the underlying pathological process and early detection of transactive response DNA-binding protein of 43 kDa pathology would facilitate the development of disease-modifying drugs. The real-Time quaking-induced conversion reaction showed the ability to detect prions in several peripheral tissues of patients with different forms of prion and prion-like diseases. Despite transactive response DNA-binding protein of 43 kDa displays prion-like properties, to date the real-Time quaking-induced conversion reaction technology has not yet been adapted to this protein. The aim of this study was to adapt the real-Time quaking-induced conversion reaction technique for the transactive response DNA-binding protein of 43 kDa substrate and to exploit the intrinsic ability of this technology to amplify minute amount of mis-folded proteins for the detection of pathological transactive response DNA-binding protein of 43 kDa species in the cerebrospinal fluid of amyotrophic lateral sclerosis and frontotemporal lobar degeneration patients. We first optimized the technique with synthetic transactive response DNA-binding protein of 43 kDa-pre-formed aggregates and with autopsy-verified brain homogenate samples and subsequently analysed CSF samples from amyotrophic lateral sclerosis and frontotemporal lobar degeneration patients and controls. Transactive response DNA-binding protein of 43 kDa real-Time quaking-induced conversion reaction was able to detect as little as 15 pg of transactive response DNA-binding protein of 43 kDa aggregates, discriminating between a cohort of patients affected by amyotrophic lateral sclerosis and frontotemporal lobar degeneration and age-matched controls with a total sensitivity of 94% and a specificity of 85%. Our data give a proof-of-concept that transactive response DNA-binding protein of 43 kDa is a suitable substrate for the real-Time quaking-induced conversion reaction. Transactive response DNA-binding protein of 43 kDa real-Time quaking-induced conversion reaction could be an innovative and useful tool for diagnosis and drug development in amyotrophic lateral sclerosis and frontotemporal lobar degeneration. The cerebrospinal fluid detection of transactive response DNA-binding protein of 43 kDa pathological aggregates may be exploited as a disease biomarker for amyotrophic lateral sclerosis and frontotemporal lobar degeneration patients