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BACKGROUND AND PURPOSE: Halofuginone is a febrifugine derivative originally isolated from Chinese traditional herb Chang Shan that exhibits anti-hypertrophic, anti-fibrotic and anti-proliferative effects. We sought to investigate whether halofuginone induced pulmonary vasodilation and attenuates chronic hypoxia-induced pulmonary hypertension (HPH). EXPERIMENTAL APPROACH: Patch-clamp experiments were conducted to examine the activity of voltage-dependent Ca(2+) channels (VDCCs) in pulmonary artery smooth muscle cells (PASMCs). Digital fluorescence microscopy was used to measure intracellular Ca(2+) concentration in PASMCs. Isolated perfused and ventilated mouse lungs were used to measure pulmonary artery pressure (PAP). Mice exposed to hypoxia (10% O(2)) for 4 weeks were used as model of HPH for in vivo experiments. KEY RESULTS: Halofuginone increased voltage-gated K(+) (K(v)) currents in PASMCs and K(+) currents through KCNA5 channels in HEK cells transfected with KCNA5 gene. HF (0.03–1 μM) inhibited receptor-operated Ca(2+) entry in HEK cells transfected with calcium-sensing receptor gene and attenuated store-operated Ca(2+) entry in PASMCs. Acute (3–5 min) intrapulmonary application of halofuginone significantly and reversibly inhibited alveolar hypoxia-induced pulmonary vasoconstriction dose-dependently (0.1–10 μM). Intraperitoneal administration of halofuginone (0.3 mg·kg(−1), for 2 weeks) partly reversed established PH in mice. CONCLUSION AND IMPLICATIONS: Halofuginone is a potent pulmonary vasodilator by activating K(v) channels and blocking VDCC and receptor-operated and store-operated Ca(2+) channels in PASMCs. The therapeutic effect of halofuginone on experimental PH is probably due to combination of its vasodilator effects, via inhibition of excitation–contraction coupling and anti-proliferative effects, via inhibition of the PI3K/Akt/mTOR signalling pathway.

OBJECTIVE: Social media is a powerful networking tool among health care organizations. This study determines correlations between program reputation and social media activity and popularity, specifically among otolaryngology residency programs. METHODS: Accredited programs, excluding military and osteopathic, in the United States were included. Activity and popularity on Facebook, Twitter, and Instagram were assessed during the same 7-month period from 2016 to 2020. Doximity Residency reputation scores (dividing programs into quartiles) and US News & World Report (comparing programs affiliated with top hospitals versus those with unranked hospitals) were utilized to compare differences based on reputation. RESULTS: Of 104 programs, 91 (88%) had social media accounts. Instagram and Twitter were more commonly used than Facebook, with 78 (75%), 49 (47%), and 42 (40%) accounts, respectively. The cumulative use of all three platforms grew yearly, while Twitter (R2 = 0.9863) and Instagram (R2 = 0.9955) presence increased exponentially. Doximity's top quartile programs had more Facebook (P = .020), Twitter (P < .001), and Instagram (P = .102) accounts. First-quartile programs also adopted each platform months before fourth-quartile programs. Stratified by US News & World Report, ranked programs had more social media accounts, with 24 (53%) on Facebook (P = .028), 32 (71%) on Twitter (P < .001), and 37 (82%) on Instagram (P = .155). Programs with higher reputations were more active and exhibited increased likes and followers over time. CONCLUSION: Social media use among otolaryngology programs has grown exponentially, with Instagram and Twitter becoming the dominant platforms. Higher ranked programs are more active on social media, have more followers, and adopt social media earlier. LEVEL OF EVIDENCE: Level 4 Laryngoscope, 2021.

The tumor-suppressive role of p53, a transcription factor that regulates the expression of many genes, has been linked to cell cycle arrest, apoptosis, and senescence. The noncanonical function or the pathogenic role of p53 has more recently been implicated in pulmonary vascular disease. We previously reported that rapid nuclear accumulation of hypoxia-inducible factor (HIF)-1α in pulmonary arterial smooth muscle cells (PASMCs) upregulates transient receptor potential channels and enhances Ca2+entry to increase cytosolic Ca2+concentration ([Ca2+]cyt). Also, we observed differences in HIF-1α/2α expression in PASMCs and pulmonary arterial endothelial cells (PAECs). Here we report that p53 is increased in PAECs, but decreased in PASMCs, isolated from mice with hypoxia-induced pulmonary hypertension (PH) and rats with monocrotaline (MCT)-induced PH (MCT-PH). The increased p53 in PAECs from rats with MCT-PH is associated with an increased ratio of Bax/Bcl-2, while the decreased p53 in PASMCs is associated with an increased HIF-1α. Furthermore, p53 is downregulated in PASMCs isolated from patients with idiopathic pulmonary arterial hypertension compared with PASMCs from normal subjects. Overexpression of p53 in normal PASMCs inhibits store-operated Ca2+entry (SOCE) induced by passive depletion of intracellularly stored Ca2+in the sarcoplasmic reticulum, while downregulation of p53 enhances SOCE. These data indicate that differentially regulated expression of p53 and HIF-1α/2α in PASMCs and PAECs and the cross talk between p53 and HIF-1α/2α in PASMCs and PAECs may play an important role in the development of PH via, at least in part, induction of PAEC apoptosis and PASMC proliferation.

An increase in cytosolic free Ca 2+ concentration ([Ca 2+ ] cyt ) in pulmonary artery smooth muscle cells (PASMCs) triggers pulmonary vasoconstriction and stimulates PASMC proliferation leading to vascular wall thickening. Here, we report that STIM2 (stromal interaction molecule 2), a Ca 2+ sensor in the sarcoplasmic reticulum membrane, is required for raising the resting [Ca 2+ ] cyt in PASMCs from patients with pulmonary arterial hypertension (PAH) and activating signaling cascades that stimulate PASMC proliferation and inhibit PASMC apoptosis. Downregulation of STIM2 in PAH-PASMCs reduces the resting [Ca 2+ ] cyt , whereas overexpression of STIM2 in normal PASMCs increases the resting [Ca 2+ ] cyt . The increased resting [Ca 2+ ] cyt in PAH-PASMCs is associated with enhanced phosphorylation (p) of CREB (cAMP response element–binding protein), STAT3 (signal transducer and activator of transcription 3), and AKT, increased NFAT (nuclear factor of activated T-cell) nuclear translocation, and elevated level of Ki67 (a marker of cell proliferation). Furthermore, the STIM2-associated increase in the resting [Ca 2+ ] cyt also upregulates the antiapoptotic protein Bcl-2 in PAH-PASMCs. Downregulation of STIM2 in PAH-PASMCs with siRNA (1) decreases the level of pCREB, pSTAT3, and pAKT and inhibits NFAT nuclear translocation, thereby attenuating proliferation, and (2) decreases Bcl-2, which leads to an increase of apoptosis. In summary, these data indicate that upregulated STIM2 in PAH-PASMCs, by raising the resting [Ca 2+ ] cyt , contributes to enhancing PASMC proliferation by activating the CREB, STAT3, AKT, and NFAT signaling pathways and stimulating PASMC proliferation. The STIM2-associated increase in the resting [Ca 2+ ] cyt is also involved in upregulating Bcl-2 that makes PAH-PASMCs resistant to apoptosis, and thus plays an important role in sustained pulmonary vasoconstriction and excessive pulmonary vascular remodeling in patients with PAH.

An increase in cytosolic Ca(2+) concentration ([Ca(2+)](cyt)) in pulmonary artery smooth muscle cells (PASMCs) triggers pulmonary vasoconstriction and stimulates PASMC proliferation leading to vascular wall thickening. Here, we report that STIM2, a Ca(2+) sensor in the sarcoplasmic reticulum (SR) membrane, is required for raising the resting [Ca(2+)](cyt) in PASMCs from patients with pulmonary arterial hypertension (PAH) and activating signaling cascades that stimulate PASMC proliferation and inhibit PASMC apoptosis. Downregulation of STIM2 in PAH-PASMCs reduces the resting [Ca(2+)](cyt), while overexpression of STIM2 in normal PASMCs increases the resting [Ca(2+)](cyt). The increased resting [Ca(2+)](cyt) in PAH-PASMCs is associated with enhanced phosphorylation (p) of CREB, STAT3 and AKT, increased NFAT nuclear translocation, and elevated level of Ki67 (a marker of cell proliferation). Furthermore, the STIM2-associated increase in the resting [Ca(2+)](cyt) also upregulates the anti-apoptotic protein Bcl-2 in PAH-PASMCs. Downregulation of STIM2 in PAH-PASMCs with siRNA a) decreases the level of pCREB, pSTAT3 and pAKT and inhibits NFAT nuclear translocation, thereby attenuating proliferation, and b) decreases Bcl-2, which leads to an increase of apoptosis. In summary, these data indicate that upregulated STIM2 in PAH-PASMCs, by raising the resting [Ca(2+)](cyt), contributes to enhancing PASMC proliferation by activating the CREB, STAT3, AKT and NFAT signaling pathways and stimulating PASMC proliferation. The STIM2-associated increase in the resting [Ca(2+)](cyt) is also involved in upregulating Bcl-2 that makes PAH-PASMCs resistant to apoptosis, and thus plays an important role in sustained pulmonary vasoconstriction and excessive pulmonary vascular remodeling in patients with PAH.