Abstract Background GRT-R910 (Gritstone bio, Inc), a self-amplifying mRNA (samRNA) vaccine expressing the spike protein plus T-cell epitopes of SARS-CoV-2 (D614G variant), was tested in a phase 1 study as a booster in healthy adults. Methods This phase 1 open-label, dose escalation study enrolled healthy adults who previously received an approved mRNA COVID-19 vaccine series. Groups of 10 adults aged 18-60 years were boosted with GRT-R910 at 3 or 6 mcg. Adults > 60 years were boosted with GRT-R910 at 3, 6, or 10 mcg. All participants > 60 years in the 6 and 10 mcg dose groups received prior mRNA COVID-19 boosters; none in other groups had prior boosts. Study boosts occurred at least 112 days after completion of primary series/boost of authorized mRNA COVID-19 vaccine or prior SARS-CoV-2 infection. Solicited local and systemic reactogenicity events were collected for 7 days, unsolicited adverse events for 28 days, and serious adverse events (SAEs) for 366 days post-vaccination. Humoral (ELISA IgG against SARS-CoV-2 RBD and neutralizing antibody against D614G and Omicron BA.4/5) are being assessed at multiple time points over 1 year after study vaccination. Participants who self-reported SARS-CohV-2 infection or receipt of non-study COVID-19 booster during the study were censored in the immunogenicity analyses. Results No severe local reactogenicity events were observed. Overall, out of 48 enrolled across all groups, 8 reported at least 1 severe systemic reactogenicity event (figure 1). Most severe systemic reactogenicity events were transient, with most graded severe for 1 day or less. No SAEs have been reported. Neutralizing antibody responses remain durable up to 1 year after 3 and 6 mcg boosts in adults 18-60 years (figure 2) and up to 6 months after 3, 6, and 10 mcg boosts in adults > 60 years (data only available through 6 months; figure 3).Figure 1:Solicited Systemic and Local Reactogenicity within 7 Days after Receipt of GRT-R910 GMT= geometric mean titer; Boxes and horizontal bars denote interquartile range (IQR) and median AUC, respectively. Whisker endpoints are equal to the maximum and minimum values below or above the median +/- 1.5 x IQR. All participants in the 3 μg GRT-R910, 18-60 yo and 6 μg GRT-R910, 18-60 yo groups received a mRNA two dose primary COVID-19 vaccination series prior to enrollment. None were previously SARS-CoV-2 infected. GMT= geometric mean titer; Boxes and horizontal bars denote interquartile range (IQR) and median AUC, respectively. Whisker endpoints are equal to the maximum and minimum values below or above the median +/- 1.5 x IQR. All participants in the 3 μg GRT-R910, > 60 yo group received a mRNA two dose primary COVID-19 vaccination series prior to enrollment. All participants in the 6 μg GRT-R910, > 60 yo and 10 μg GRT-R910, > 60 yo groups received a mRNA two dose primary COVID-19 vaccination series plus a mRNA booster vaccine prior to enrollment. Two participants each in the 6 μg GRT-R910, > 60 yo and 10 μg GRT-R910, > 60 yo groups had a previous COVID-19 infection at enrollment (green dots). D1, D15, D29 testing for Groups 9 and 10 are planned against BA.4/5. Conclusion While transient systemic reactogenicity with GRT-R910 as a booster was observed, no safety signals were identified. Preliminary immunogenicity data demonstrate durable neutralizing antibody responses for 6-12 months in both younger and older age groups. Forthcoming T cell response data will aid in assessing the immunogenicity of this novel vaccine. Disclosures Nadine Rouphael, MD, Icon, EMMES, Sanofi, Seqirus, Moderna: Advisor/Consultant Anna Wald, MD, MPH, Aicuris: Advisor/Consultant|Bayer: Advisor/Consultant|Curevo: Participation on Data Safety Monitoring Board|GSK: Grant/Research Support|Sanofi: Grant/Research Support|UpToDate: Royalties or licenses Pedro Garbes, MD, Gritstone bio, Inc.: Employee|Gritstone bio, Inc.: Employee|Gritstone bio, Inc.: Stocks/Bonds|Gritstone bio, Inc.: Stocks/Bonds Karin Jooss, PhD, Gritstone bio: employee|Gritstone bio: Stocks/Bonds Andrew Allen, MD, PhD, Gritstone bio: Board Member|Gritstone bio: Ownership Interest|Gritstone bio: Stocks/Bonds Amanda Eaton, MBA, Moderna: Grant/Research Support David M. Koelle, MD, Curevo Vaccines: Board Member|MaxHealth LLC: Board Member|Sanofi Pasteur: Grant/Research Support Daniel F. Hoft, MD, PhD, Moderna: Advisor/Consultant|Poolbeg: Advisor/Consultant
Leptin, a peptide hormone normally associated with body weight homeostasis, is implicated in the generation of obesity-induced hypertension. Administration of leptin increases sympathetic nerve activity and blood pressure; however, the neural circuity involved in this pressor effect is not clearly defined. In this review we describe experiments in which pseudorabies virus was injected into the heart, kidney and the vasculature within skeletal muscle to reveal the distribution of neurones in the hypothalamus that project to these cardiovascular tissues. This distribution is compared to the well-documented distribution of leptin receptors. Finally we discuss microinjection studies designed to examine the effect of leptin, in these regions, on sympathetic nerve discharge and arterial blood pressure. Leptin injected directly into the ventromedial hypothalamus, arcuate nucleus and lateral hypothalamic area (particularly the perifornical area) increased lumbar sympathetic nerve activity. In addition, microinjection into the ventromedial hypothalamus and parvocellular paraventricular nucleus increased blood pressure. Our results demonstrate a discrete set of hypothalamic pathways that may underlie the involvement of leptin in obesity-induced hypertension.
Abstract The concept of ‘command neurons’, whereby single neurons mediate complex and complementary motor functions to generate a stereotyped behaviour, is well developed in invertebrate physiology. The term has also been adopted more recently to explain the neural basis of ‘fight or flight’. In this study we have investigated the possibility that single lateral hypothalamic neurons have the necessary neuroanatomical connections to coordinate two complementary limbs of body weight control, feeding and thermogenesis, thereby acting as ‘command neurons’. The transynaptic retrograde transport of pseudorabies virus (Bartha) from a thermogenic endpoint in the brown adipose tissue of rats has been used in conjunction with other neuronal tracers, introduced into putative CNS feeding centres, to assess the potential for the involvement of command neurons in coordinating these processes. In discrete regions of the lateral hypothalamus, neurons have been identified which have the necessary complement of orexigenic peptides and collateral branching axons to both putative feeding sites and thermogenic sites in brown fat to qualify as candidate central command neurons controlling body weight.
The distributions of angiotensin AT1 and AT2 receptors have been mapped by in vitro autoradiography throughout most tissues of many mammals, including humans. In addition to confirming that AT1 receptors occur in sites known to be targets for the physiologic actions of angiotensin, such as the adrenal cortex and medulla, renal glomeruli and proximal tubules, vascular and cardiac muscle, and brain circumventricular organs, many new sites of action have been demonstrated. In the kidney, AT1 receptors occur in high density in renal medullary interstitial cells. The function of these cells, which span the interstitial space between the tubules and the vasa rectae, remains to be determined. Renal medullary interstitial cells possess receptors for a number of vasoactive hormones in addition to AT1 receptors and this, in concert with their anatomical location, suggest that they may be important for the regulation of fluid reabsorption or renal medullary blood flow. In the heart, the highest densities of AT1 receptors occur in association with the conduction system and vagal ganglia. In the central nervous system, high AT1 receptor densities occur in many regions behind the blood-brain barrier, supporting a role for neurally derived angiotensin as a neuromodulator. The physiologic role of angiotensin in many of these brain sites remains to be determined. The AT2 receptor also has a characteristic distribution in several tissues including the adrenal gland, heart, and brain. The role of this receptor in physiology is being elucidated, but it appears to participate in development. Thus, receptor binding studies, localizing the distribution of AT1 and AT2 receptors, outline a number of regions where the actions of angiotensin are known but also provide many insights into novel physiologic roles of this peptide.
Objectives: The ‘legacy effect’ of persistently lower blood pressure in SHR is observed after short-term treatment with angiotensin converting enzyme inhibitor (ACEi) or angiotensin II receptor blocker (ARB) antihypertensive drugs and is associated with changes in renal function. This presumably involves resetting of the genetic program leading to hypertension in SHR. Circular RNAs (circRNA) are novel non-coding RNAs that regulate mRNA expression post-transcriptionally and might be relevant to the legacy effect. Our aim was to study circRNA expression in the SHR after antihypertensive treatment. Methods: We treated male SHR with an ACEi (perindopril), an angiotensin II receptor blocker (losartan) or a vasodilator (hydralazine) from 10–14 weeks of age. Renal cortex and cardiac left ventricular tissues were collected at 20-weeks of age (n = 3–5 per group). We measured the expression of heart related circular RNA (Hrcr), circular titin (cTtn) and circular foxhead box O3 (cFoxo3) using quantitative real-time PCR. These circRNAs have been implicated in cardiac hypertrophy and heart failure in mice. Statistical analysis was performed using one-way ANOVA and significance was set as P < 0.05. Results: Hrcr and cFoxo3 were downregulated in renal cortex at 20-weeks when compared with vehicle after all antihypertensive treatments (P < 0.01 for all). However, renal cortical cTtn expression was upregulated only after treatment with ACEi (P < 0.05) or ARB (P < 0.05). Differences in circRNA expression were not observed in heart tissues. Conclusion: Early antihypertensive treatment in SHR resets circRNA expression in renal cortices of SHR but not in the heart. This indicates tissue-specific regulation of circRNA expression might be important in reprogramming genetic hypertension by early renin-angiotensin system blocking drugs in SHR.
Brief treatment with renin-angiotensin system (RAS) inhibitors permanently reduces the genetic hypertension of the spontaneously hypertensive rat (SHR). The kidney is involved in this reprogramming, but relevant molecular genetic changes are unknown. We studied SHR kidney RNA differential expression (controlling for non-specific effects of lower BP) and DNA methylation 6 weeks after treatment with the angiotensin receptor blocker losartan from 10 to 14 weeks of age. RNA sequencing revealed a significant 6-fold (P < 0.0001) increase in renin gene (Ren) expression during treatment. Six weeks later direct mean arterial pressure remained lower than untreated SHR (123 vs 140 mmHg, P = 0.001) and kidney Ren expression was reduced by 23% (P = 0.03) and DNA methylation within the Ren promoter region was significantly increased (P = 0.04). Experiments with the ACE inhibitor perindopril and renin immunohistochemical analyses confirmed significant long-term reduction in kidney Ren expression following RAS inhibition. Genomic RNA sequencing analysis identified 13 candidate genes (Grhl1, Ammecr1l, Hs6st1, Nfil3, Fam221a, Lmo4, Adamts1, Cish, Hif3a, Bcl6, Rad54l2, Adap1, Dok4) and the miRNA miR-145-3p that were significantly differentially expressed and correlated closely with decreased Ren expression. Ten of the candidates were central to gene networks that exhibited significant enrichment for genes relevant to BP and the RAS. We propose that reduced renin gene expression is a legacy of early RAS inhibition and responsible for the persistent reduction in BP in SHR.
Drugs that target the Renin-Angiotensin System (RAS) have recently come into focus for their potential utility as cancer treatments. The use of Angiotensin Receptor Blockers (ARBs) and Angiotensin-Converting Enzyme (ACE) Inhibitors (ACEIs) to manage hypertension in cancer patients is correlated with improved survival outcomes for renal, prostate, breast and small cell lung cancer. Previous studies demonstrate that the Angiotensin Receptor Type I (AT1R) is linked to breast cancer pathogenesis, with unbiased analysis of gene-expression studies identifying significant up-regulation of AGTR1, the gene encoding AT1R in ER+ve/HER2-ve tumors correlating with poor prognosis. However, there is no evidence, so far, of the functional contribution of AT1R to breast tumorigenesis. We explored the potential therapeutic benefit of ARB in a carcinogen-induced mouse model of breast cancer and clarified the mechanisms associated with its success.Mammary tumors were induced with 7,12-dimethylbenz[α]antracene (DMBA) and medroxyprogesterone acetate (MPA) in female wild type mice and the effects of the ARB, Losartan treatment assessed in a preventative setting (n = 15 per group). Tumor histopathology was characterised by immunohistochemistry, real-time qPCR to detect gene expression signatures, and tumor cytokine levels measured with quantitative bioplex assays. AT1R was detected with radiolabelled ligand binding assays in fresh frozen tumor samples.We showed that therapeutic inhibition of AT1R, with Losartan, resulted in a significant reduction in tumor burden; and no mammary tumor incidence in 20% of animals. We observed a significant reduction in tumor progression from DCIS to invasive cancer with Losartan treatment. This was associated with reduced tumor cell proliferation and a significant reduction in IL-6, pSTAT3 and TNFα levels. Analysis of tumor immune cell infiltrates, however, demonstrated no significant differences in the recruitment of lymphocytes or tumour-associated macrophages in Losartan or vehicle-treated mammary tumors.Analysis of AT1R expression with radiolabelled ligand binding assays in human breast cancer biopsies showed high AT1R levels in 30% of invasive ductal carcinomas analysed. Furthermore, analysis of the TCGA database identified that high AT1R expression to be associated with luminal breast cancer subtype.Our in vivo data and analysis of human invasive ductal carcinoma samples identify the AT1R is a potential therapeutic target in breast cancer, with the availability of a range of well-tolerated inhibitors currently used in clinics. We describe a novel signalling pathway critical in breast tumorigenesis, that may provide new therapeutic avenues to complement current treatments.
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