Three-dimensional (3D) bio-printing is a revolutionary technology to reproduce a 3D functional living tissue scaffold in-vitro through controlled layer-by-layer deposition of biomaterials along with high precision positioning of cells. Due to its bio-compatibility, natural hydrogels are commonly considered as the scaffold material. However, the mechanical integrity of a hydrogel material, especially in 3D scaffold architecture, is an issue. In this research, a novel hybrid hydrogel, that is, sodium alginate with carboxymethyl cellulose (CMC) is developed and systematic quantitative characterization tests are conducted to validate its printability, shape fidelity and cell viability. The outcome of the rheological and mechanical test, filament collapse and fusion test demonstrate the favorable shape fidelity. Three-dimensional scaffold structures are fabricated with the pancreatic cancer cell, BxPC3 and the 86% cell viability is recorded after 23 days. This hybrid hydrogel can be a potential biomaterial in 3D bioprinting process and the outlined characterization techniques open an avenue directing reproducible printability and shape fidelity.

Airway hyperresponsiveness and inflammation are fundamental hallmarks of allergic asthma that are accompanied by increases in certain polycations, such as eosinophil cationic protein. Levels of these cations in body fluids correlate with asthma severity. We show that polycations and elevated extracellular calcium activate the human recombinant and native calcium-sensing receptor (CaSR), leading to intracellular calcium mobilization, cyclic adenosine monophosphate breakdown, and p38 mitogen-activated protein kinase phosphorylation in airway smooth muscle (ASM) cells. These effects can be prevented by CaSR antagonists, termed calcilytics. Moreover, asthmatic patients and allergen-sensitized mice expressed more CaSR in ASMs than did their healthy counterparts. Indeed, polycations induced hyper-reactivity in mouse bronchi, and this effect was prevented by calcilytics and absent in mice with CaSR ablation from ASM. Calcilytics also reduced airway hyperresponsiveness and inflammation in allergen-sensitized mice in vivo. These data show that a functional CaSR is up-regulated in asthmatic ASM and targeted by locally produced polycations to induce hyperresponsiveness and inflammation. Thus, calcilytics may represent effective asthma therapeutics.

There is increasing recognition that the sex hormones (estrogen, progesterone, and testosterone) have biological and pathophysiological actions in peripheral, non-reproductive organs, including the lung. Clinically, sex differences in the incidence, morbidity and mortality of lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, lung cancer and pulmonary hypertension have been noted, although intrinsic sex differences vs. the roles of sex steroids are still not well-understood. Accordingly, it becomes important to ask the following questions: 1) Which sex steroids are involved? 2) How do they affect different components of the lung under normal circumstances? 3) How does sex steroid signaling change in or contribute to lung disease, and in this regard, are sex steroids detrimental or beneficial? As our understanding of sex steroid signaling in the lung improves, it is important to consider whether such information can be used to develop new therapeutic strategies to target lung diseases, perhaps in both sexes or in a sex-specific manner. In this review, we focus on the basics of sex steroid signaling, and the current state of knowledge regarding how they influence structure and function of specific lung components across the life span and in the context of some important lung diseases. We then summarize the potential for sex steroids as useful biomarkers and therapeutic targets in these lung diseases as a basis for future translational research in the area of gender and individualized medicine.

Maintenance of blood oxygen saturation dictates supplemental oxygen administration to premature infants, but hyperoxia predisposes survivors to respiratory diseases such as asthma. Although much research has focused on oxygen effects on alveoli in the setting of bronchopulmonary dysplasia, the mechanisms by which oxygen affects airway structure or function relevant to asthma are still under investigation. We used isolated human fetal airway smooth muscle (fASM) cells from 18-20 postconceptual age lungs (canalicular stage) to examine oxygen effects on intracellular Ca(2+) ([Ca(2+)](i)) and cellular proliferation. fASM cells expressed substantial smooth muscle actin and myosin and several Ca(2+) regulatory proteins but not fibroblast or epithelial markers, profiles qualitatively comparable to adult human ASM. Fluorescence Ca(2+) imaging showed robust [Ca(2+)](i) responses to 1 μM acetylcholine (ACh) and 10 μM histamine (albeit smaller and slower than adult ASM), partly sensitive to zero extracellular Ca(2+). Compared with adult, fASM showed greater baseline proliferation. Based on this validation, we assessed fASM responses to 10% hypoxia through 90% hyperoxia and found enhanced proliferation at <60% oxygen but increased apoptosis at >60%, effects accompanied by appropriate changes in proliferative vs. apoptotic markers and enhanced mitochondrial fission at >60% oxygen. [Ca(2+)](i) responses to ACh were enhanced for <60% but blunted at >60% oxygen. These results suggest that hyperoxia has dose-dependent effects on structure and function of developing ASM, which could have consequences for airway diseases of childhood. Thus detrimental effects on ASM should be an additional consideration in assessing risks of supplemental oxygen in prematurity.

Caveolae, plasma membrane invaginations with constitutive caveolin proteins, harbour proteins involved in intracellular calcium ([Ca2+]i) regulation. In human airway smooth muscle (ASM), store-operated Ca2+ entry (SOCE) is a key component of [Ca2+]i regulation, and contributes to increased [Ca2+]i in inflammation. SOCE involves proteins Orai1 and stromal interaction molecule (STIM)1. We investigated the link between caveolae, SOCE and inflammation in ASM. [Ca2+]i was measured in human ASM cells using fura-2. Small interference RNA (siRNA) or overexpression vectors were used to alter expression of caveolin-1 (Cav-1), Orai1 or STIM1. Tumour necrosis factor (TNF)-α was used as a representative pro-inflammatory cytokine. TNF-α increased SOCE following sarcoplasmic reticulum Ca2+ depletion, and increased whole-cell and caveolar Orai1 (but only intracellular STIM1). Cav-1 siRNA decreased caveolar and whole-cell Orai1 (but not STIM1) expression, and blunted SOCE, even in the presence of TNF-α. STIM1 overexpression substantially enhanced SOCE: an effect only partially reversed by Cav-1 siRNA. In contrast, Orai1 siRNA substantially blunted SOCE even in the presence of TNF-α. Cav-1 overexpression significantly increased Orai1 expression and SOCE, especially in the presence of TNF-α. These results demonstrate that caveolar expression and regulation of proteins such as Orai1 are important for [Ca2+]i regulation in human ASM cells and its modulation during inflammation.