Dysregulated Cell Signaling in Pulmonary Emphysema

Pulmonary emphysema is characterized by the destruction of alveolar septa and irreversible airflow limitation. Cigarette smoking is the primary cause of this disease development. It induces oxidative stress and disturbs lung physiology and tissue homeostasis. Alveolar type II (ATII) cells have stem cell potential and can repair the denuded epithelium after injury; however, their dysfunction is evident in emphysema. There is no effective treatment available for this disease. Challenges in this field involve the large complexity of lung pathophysiological processes and gaps in our knowledge on the mechanisms of emphysema progression. It implicates dysregulation of various signaling pathways, including aberrant inflammatory and oxidative responses, defective antioxidant defense system, surfactant dysfunction, altered proteostasis, disrupted circadian rhythms, mitochondrial damage, increased cell senescence, apoptosis, and abnormal proliferation and differentiation. Also, genetic predispositions are involved in this disease development. Here, we comprehensively review studies regarding dysregulated cell signaling, especially in ATII cells, and their contribution to alveolar wall destruction in emphysema. Relevant preclinical and clinical interventions are also described.

Differential activation of Ca2+ influx channels modulate stem cell potency, their proliferation/viability and tissue regeneration

Stem cells have indefinite self-renewable capability; however, factors that modulate their pluripotency/function are not fully identified. Here we show that store-dependent Ca2+ entry is essential for modulating the function of bone marrow-derived mesenchymal stem cells (MSCs). Increasing external Ca2+ modulated cell cycle progression that was critical for MSCs survival. Additionally, Ca2+ was critical for stem proliferation, its differentiation, and maintaining stem cell potential. Ca2+ channel characterization, including gene silencing, showed two distinct Ca2+ entry channels (through Orai1/TRPC1 or via Orai3) that differentially regulate the proliferation and viability of MSCs. Importantly, NFκB translocation, but not JNK/ERK into the nucleus, was observed upon store depletion, which was blocked by the addition of Ca2+ channel inhibitors. Radiation lead to a decrease in saliva secretion, decrease in acinar cell number, and enlarged ducts were observed, which were restored by the transplantation of stem cells that were propagated in higher Ca2+. Finally radiation showed a decrese in TRPC1 expression along with a decrese in AQP5, which was again restored upon MSC tranplantation. Together these results suggest that Ca2+ entry is essential for stem cell function that could be critical for regenerative medicine.

Identification and Quantification of Malignant Cells in Cerebrospinal Fluid

Usual diagnostic methods of leptomeningeal metastases (LM) in CerebroSpinal fluid (CSF), lack both specificity and sensitivity. The Veridex CellSearch® technique quantifying circulating tumour cells (CTCs) in blood was adapted to detect Tumour Cells (CSFTCs) in CSF from cancer patients with LM. CSF samples from 60 patients with established or suspected breast cancer or lung cancer LM and/or melanoma were evaluated. 5 mL CSF samples were collected on CellSave® preservative and analyzed within 3 days after CSF sampling. Gold Standard cytological analysis on 1 to 10 mL CSF samples from patients with established LM allowed sometimes the detection but usually not the quantification of TCs. In established LM, EpCAM+/cytokeratin+ or CD146+/HMW-MAA+ nucleated (DAPI+) cells were observed and enumerated with precision from one to up to 10 000 cells/mL. Their morphology on digital images galleries could be discriminant between breast and lung cancer. This methodology, established on a limited volume of CSF compared to the Gold Standard and allowing delayed processing, is of great interest in the diagnosis and follow-up of cancer patients with LM. The reliability of the method also opens new fields of investigation for other biological fluids and to precise the stem cell potential of metastatic cells in CSF.