Fork head controls the timing and tissue selectivity of steroid-induced developmental cell death

Cell death during Drosophila melanogaster metamorphosis is controlled by the steroid hormone 20-hydroxyecdysone (20E). Elements of the signaling pathway that triggers death are known, but it is not known why some tissues, and not others, die in response to a particular hormone pulse. We found that loss of the tissue-specific transcription factor Fork head (Fkh) is both required and sufficient to specify a death response to 20E in the larval salivary glands. Loss of fkh itself is a steroid-controlled event that is mediated by the 20E-induced BR-C gene, and that renders the key death regulators hid and reaper hormone responsive. These results implicate the D. melanogaster FOXA orthologue Fkh with a novel function as a competence factor for steroid-controlled cell death. They explain how a specific tissue is singled out for death, and why this tissue survives earlier hormone pulses. More generally, they suggest that cell identity factors like Fkh play a pivotal role in the normal control of developmental cell death

Increased Ca2+ signaling through CaV1.2 promotes bone formation and prevents estrogen deficiency-induced bone loss

While the prevalence of osteoporosis is growing rapidly with population aging, therapeutic options remain limited. Here, we identify potentially novel roles for CaV1.2 L-type voltage-gated Ca2+ channels in osteogenesis and exploit a transgenic gain-of-function mutant CaV1.2 to stem bone loss in ovariectomized female mice. We show that endogenous CaV1.2 is expressed in developing bone within proliferating chondrocytes and osteoblasts. Using primary BM stromal cell (BMSC) cultures, we found that Ca2+ influx through CaV1.2 activates osteogenic transcriptional programs and promotes mineralization. We used Prx1-, Col2a1-, or Col1a1-Cre drivers to express an inactivation-deficient CaV1.2 mutant in chondrogenic and/or osteogenic precursors in vivo and found that the resulting increased Ca2+ influx markedly thickened bone not only by promoting osteogenesis, but also by inhibiting osteoclast activity through increased osteoprotegerin secretion from osteoblasts. Activating the CaV1.2 mutant in osteoblasts at the time of ovariectomy stemmed bone loss. Together, these data highlight roles for CaV1.2 in bone and demonstrate the potential dual anabolic and anticatabolic therapeutic actions of tissue-specific CaV1.2 activation in osteoblasts

Clinical Association of Achilles Tendinopathy and Hypertension Mediated by CaV1.2 Voltage-gated Ca2+ Channel

Category: Basic Sciences/Biologics; Hindfoot Introduction/Purpose: The Achilles tendon is subject to acute- and overuse-injuries, which may result in degenerative tendinopathy. Achilles tendinopathy is associated with pain, disability, and functional limitations. While some patients benefit from therapy and conservative measures, many progress to operative intervention. The pathogenic mechanisms of Achilles tendinopathy are largely unknown. Using novel transgenic mouse models with CaV1.2 (a voltage gated calcium channel) wildtype or a gain-of-function mutant channel, we observed potent regulatory effects of increased Ca2+ influx through CaV1.2 on Achilles tendinopathy development. CaV1.2 expression and activity has also been shown to contribute to hypertension amongst other systemic disease. We hypothesized that aberrant CaV1.2 function is a common pathogenic mechanism both hypertension and Achilles tendinopathy. To test this hypothesis, we performed an association study between two diseases. Methods: A case-control study was performed to investigate the association between Achilles tendinopathy and hypertension using TriNetX mulit-center clinical database. We identified Achilles tendinopathy and hypertension patients based on their ICD-10 codes. Chi-squared test, odds ratio (OR) and 95% confidence interval (CI) were used to detect the correlation between these two diseases. To elucidate the role of CaV1.2 in the association of Achilles tendinopathy and hypertension, we performed a retrospective cohort study with the exposure cohort defined as all subjects with hypertension and a calcium channel blocker (CCB) prescription preceding a diagnosed tendinopathy from January 1, 2011 to December 31, 2015. A matched cohort was defined as the subjects with hypertension but on medications other than CCBs. A 7-year follow-up was obtained for the outcome Achilles tendinopathy. Relative risk (RR) and hazard ratio (HR) were used to detect the effect of CCBs and other anti- hypertensives on the development of tendinopathy. Results: We determined that hypertension is more prevalent in patients with Achilles tendinopathy (42.4%) compared to those without (12.6%). The incidence of Achilles tendinopathy is significantly correlated with hypertension (p < 0.0001; OR=3.17, 95%CI=3.11-3.22). Furthermore, hypertension patients on CCBs had a 28% decrease in Achilles tendinopathy risk when compared with hypertensive patients on medications other than CCBs (RR=0.72, 95%CI=0.60-0.86, p< 0.0001). A cox proportional hazards model corroborated the findings, with hypertensive patients on CCBs having 26% decreased incidence of Achilles tendinopathy than patients on other medications (HR=0.74, 95%CI=0.62-0.88, p< 0.0001). In contrast, we found no significant effect of angiotensin-converting enzyme inhibitors (no direct effect on Calcium channel activity) on the incidence of Achilles tendinopathy (HR=0.99, 95%CI=0.88-1.10, p=0.8273). Conclusion: There may be a correlation between Achilles tendinopathy and other common systemic diseases such as hypertension, as well as potential treatment pathways. Our study of the TriNetX clinical database provides evidence that CaV1.2 expression/activity is a potential molecular mechanism underlying Achilles tendinopathy. Additionally, an effect of CCBs in hypertensive patients may be to lower the incidence of Achilles tendinopathy by inhibiting L-type voltage-gated Ca2+ channel (including CaV1.2) signaling in tenocytes. Our finding will provide a rationale for further investigation of this association, including a potential for repurposing FDA-approved generic CCBs to prevent or treat Achilles tendinopathy

Oxytocin Modulates Nociception as an Agonist of Pain-Sensing TRPV1

Summary: Oxytocin is a hormone with various actions. Oxytocin-containing parvocellular neurons project to the brainstem and spinal cord. Oxytocin release from these neurons suppresses nociception of inflammatory pain, the molecular mechanism of which remains unclear. Here, we report that the noxious stimulus receptor TRPV1 is an ionotropic oxytocin receptor. Oxytocin elicits TRPV1 activity in native and heterologous expression systems, regardless of the presence of the classical oxytocin receptor. In TRPV1 knockout mice, DRG neurons exhibit reduced oxytocin sensitivity relative to controls, and oxytocin injections significantly attenuate capsaicin-induced nociception in in vivo experiments. Furthermore, oxytocin potentiates TRPV1 in planar lipid bilayers, supporting a direct agonistic action. Molecular modeling and simulation experiments provide insight into oxytocin-TRPV1 interactions, which resemble DkTx. Together, our findings suggest the existence of endogenous regulatory pathways that modulate nociception via direct action of oxytocin on TRPV1, implying its analgesic effect via channel desensitization. : Oxytocin is known to suppress painful stimuli of inflammatory origin. Nersesyan et al. now find that oxytocin attenuates pain via the pain-sensing receptor TRPV1. Keywords: transient receptor potential vanilloid 1, TRPV1 ion channel, oxytocin, nociception, oxytocin receptor, planar lipid bilayers, molecular dynamics simulations, MD simulation

Polyester Modification of the Mammalian TRPM8 Channel Protein: Implications for Structure and Function

The TRPM8 ion channel is expressed in sensory neurons and is responsible for sensing environmental cues, such as cold temperatures and chemical compounds, including menthol and icilin. The channel functional activity is regulated by various physical and chemical factors and is likely to be preconditioned by its molecular composition. Our studies indicate that the TRPM8 channel forms a structural-functional complex with the polyester poly-(R)-3-hydroxybutyrate (PHB). We identified by mass spectrometry a number of PHB-modified peptides in the N terminus of the TRPM8 protein and in its extracellular S3-S4 linker. Removal of PHB by enzymatic hydrolysis and site-directed mutagenesis of both the serine residues that serve as covalent anchors for PHB and adjacent hydrophobic residues that interact with the methyl groups of the polymer resulted in significant inhibition of TRPM8 channel activity. We conclude that the TRPM8 channel undergoes posttranslational modification by PHB and that this modification is required for its normal function

Outcomes and Toxicities of Modern Combined Modality Therapy with Atezolizumab Plus Bevacizumab and Radiation Therapy for Hepatocellular Carcinoma

Atezolizumab plus bevacizumab has become frontline therapy for unresectable HCC. The compatibility of atezolizumab/bevacizumab with liver-directed RT has not been reported. Methods: HCC patients treated with liver-directed RT and atezolizumab/bevacizumab between 1/2020&ndash;11/2021 were included. Toxicity and outcomes were retrospectively recorded. For ALCs, we matched the analysis to a previously cohort of RT-treated HCC patients who did not receive atezolizumab/bevacizumab. Survival and time-to-liver-failure were analyzed using Kaplan&ndash;Meier. Results: Of 21 patients, with a median follow-up of 9.5 months, the median OS was 16.1 months. Post-RT, all patients had reduced tumors or treatment response. There were no &ge;Grade 3 RT-related toxicities. Autoimmune complications occurred in two patients (9.5%), and GI bleeding in three patients (14.3%). Liver function remained stable post-RT. There was a marked decrease in ALCs immediately post-RT (post-RT/pre-RT ratio 47.3%, p &lt; 0.0001), restored by 1 month to pre-treatment baseline (1-month post-RT/pre-RT ratio 95.1%, n.s.). Compared to HCC patients treated with RT alone, post-RT ALC recovery was faster with atezolizumab/bevacizumab (p = 0.009). Conclusion: In this first reported experience of RT with modern systemic therapy for HCC, combination therapy is safe and well-tolerated. As a favorable prognosticator, there appears to be faster recovery of ALC among patients who received RT with atezolizumab/bevacizumab