Role of Neural (N)-Cadherin in Breast Cancer Cell Stemness and Dormancy in the Bone Microenvironment.

Breast cancer cells that interact with spindle-shaped N-Cadherin+ Osteoblasts (SNOs) are recognised to become dormant through a Notch2-dependent mechanism. We found that Notch2High human BrCa MDA-MB231 (MDA) cells also expressed high level of N-Cadherin. This prompted us to hypothesize that N-Cadherin could have a role in MDA-SNO interaction. Of note, the expression of N-Cadherin in MDA cells reduced tumour incidence and bone osteolysis in BrCa mouse model. Moreover, similarly to Notch2High MDA cells, the N-CadherinHigh MDA cells revealed a high expression of the canonical Haematopoietic Stem cell (HSC) markers, suggesting an HSC mimicry, associated with higher ability to form mammospheres. Interestingly, N-CadherinHigh MDA cells showed greater capacity to adhere to SNOs, while the inhibition of SNO-mediating MDA cell proliferation was unremarkable. To investigate whether these features were shared by mouse BrCa, we used the 4T1 cell line in which N-Cadherin expression was abolished and then rescued. At variance with MDA cells, 4T1 cells expressing N-Cadherin revealed that the latter was associated with a lower expression of the HSC marker, Cxcr4, along with a lower capacity to form mammospheres. Furthermore, the rescue of N-Cadherin expression increased cell-cell adhesion and reduced proliferation of 4T1 cells when they were co-plated with SNOs. In conclusion, we demonstrated that: (i) N-CadherinHigh and Notch2High MDA cells showed similar HSC mimicry and dormancy features; (ii) N-Cadherin mediated BrCa-SNO adhesion; (iii) N-Cadherin had a positive Notch2-dependent role on SNO-induced dormancy and HSC mimicry in MDA cells, and a negative role in 4T1 cell stemness and HSC mimicry.

Transcriptomic and bioinformatic analysis of Clcn7-dependent Autosomal Dominant Osteopetrosis type 2. Preclinical and clinical implications.

Autosomal Dominant Osteopetrosis type 2 (ADO2) is a rare genetic disease characterized by dense yet fragile bones. To date, the radiological approach remains the gold standard for ADO2 diagnosis. However, recent observations unveiled that ADO2 is a systemic disease affecting various organs beyond bone, including lung, kidney, muscle, and brain. Monitoring disease status and progression would greatly benefit from specific biomarkers shared by the affected organs. In this work, data derived from RNA deep sequencing (RNA dSeq) of bone, lung, kidney, muscle, brain, and osteoclasts isolated from wildtype (WT) and Clcn7G213R ADO2 mice were subjected to gene ontology and pathway analyses. Results showed the presence of alterations in gene ontology terms and pathways associated with bone metabolism and osteoclast biology, including JAK-STAT, cytokine-cytokine receptor, and hematopoietic cell lineage. Furthermore, in line with the multiorgan alterations caused by ADO2, the analysis of soft organs showed an enrichment of PPAR and neuroactive ligand-receptor interaction pathways known to be involved in the onset of tissue fibrosis and behavioral alterations, respectively. Finally, we observed the modulations of potential ADO2 biomarkers in organs and cells of ADO2 mice and in the peripheral blood mononuclear cells of patients, using conventional methods. Of note, some of these biomarkers could be possibly responsive to an effective experimental therapy based on a mutation-specific siRNA. Overall, the identified gene signature and the soluble forms of the encoded proteins could potentially represent reliable disease biomarkers that could improve the ADO2 diagnosis, the monitoring of both the skeletal and non-skeletal dysfunctions, and the assessment of the response to therapy.

Evolution of Human Memory B Cells From Childhood to Old Age.

High quality medical assistance and preventive strategies, including pursuing a healthy lifestyle, result in a progressively growing percentage of older people. The population and workforce is aging in all countries of the world. It is widely recognized that older individuals show an increased susceptibility to infections and a reduced response to vaccination suggesting that the aged immune system is less able to react and consequently protect the organism. The SARS-CoV-2 pandemic is dramatically showing us that the organism reacts to novel pathogens in an age-dependent manner. The decline of the immune system observed in aging remains unclear. We aimed to understand the role of B cells. We analyzed peripheral blood from children (4-18 years); young people (23-60 years) and elderly people (65-91 years) by flow cytometry. We also measured antibody secretion by ELISA following a T-independent stimulation. Here we show that the elderly have a significant reduction of CD27dull memory B cells, a population that bridges innate and adaptive immune functions. In older people, memory B cells are mostly high specialized antigen-selected CD27bright. Moreover, after in vitro stimulation with CpG, B cells from older individuals produced significantly fewer IgM and IgA antibodies compared to younger individuals. Aging is a complex process characterized by a functional decline in multiple physiological systems. The immune system of older people is well equipped to react to often encountered antigens but has a low ability to respond to new pathogens.