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Background: Alterations in cardiovascular function are key features of severe acute pancreatitis (AP) and contribute substantially to mortality. Although sex differences in cardiovascular diseases are well recognized, with males generally exhibiting higher risk and poorer outcomes, their influence on AP-associated cardiovascular responses remains poorly defined. Therefore, we hypothesized that cerulein-induced AP causes severity-dependent and sex-specific changes in vascular integrity and cardiac function. Methods: Obesity has been associated with more severe forms of AP. Thus, mild and severe AP were induced by cerulein injections (100µg/kg/h×12) in lean (n=10 males, n=13 females) and obese (n=9 males, n=12 females) C57BL/6J mice, respectively. Vascular permeability was assessed by FITC-dextran extravasation. Cardiac function was assessed by echocardiography before and after cerulein injection. Cytokines were measured with multi-plex cytokine array and the role of angiopoietin-2 (Angpt2), an endothelial-derived regulator of vascular and cardiac responses, was evaluated using a neutralizing antibody. Results: Vascular permeability did not differ significantly between sexes in either AP model. In mild AP, males and females showed comparable increases in systolic function; however, in severe AP, only female mice maintained this adaptive systolic augmentation, assessed by fractional shortening (FS; 25.78±0.27% at baseline vs. 43.44±0.57% at endpoint, n=12, p<0.0001). This impaired cardiac adaptation in males was accompanied by increased myocardial inflammatory cytokines and elevated circulating free fatty acids. Among ten circulating cytokines measured, Angpt2 levels were significantly higher in males than females (male: 63.50±1.52ng/mL, n=9 vs. female: 41.37±2.68ng/mL, n=6, p=0.013) and were negatively correlated with systolic performance (FS; R 2 =0.75, p<0.0001), while positively associated with preload (end-diastolic volume; R 2 =0.55, p=0.0015). Unexpectedly, Angpt2 neutralization did not improve the cardiac adaptations in males and instead worsened cardiac performance as reflected by reduced FS (control IgG: 32.83±1.47%, n=4 vs. Anti-Angpt2: 22.88±0.64%, n=5, p=0.013) in severe AP. Conclusions: AP elicits both sex-dependent and sex-independent cardiovascular responses, with female mice exhibiting preserved cardiac adaptation, and Angpt2 is a potential compensatory mediator of cardiac protection in severe AP.

Background: The cardiac hormone atrial natriuretic peptide is the endogenous ligand for the guanylyl cyclase A (GC-A) receptor. The ANP/GC-A/cGMP pathway is a key regulator of cardiorenal and metabolic homeostasis. Beyond its classical natriuretic and vasodilatory roles, emerging evidence reveals that ANP via GC-A stimulates lipolysis in human adipocytes and modulates insulin secretion. Notably, the ANP gene variant rs5068, which enhances ANP production, is associated with reduced risk of obesity and metabolic syndrome in humans. We recently engineered CRRL191, a novel best-in-class GC-A agonist, with superior receptor activation and greater resistance to degradation by neprilysin and insulin degrading enzyme resulting in greater blood pressure lowering and natriuretic effects than ANP. Given the metabolic properties of GC-A signaling, we investigated CRRL191’s metabolic effects on lipolysis and insulin secretion in pancreatic, including its interaction with GLP-1. Hypothesis: CRRL191 exerts potent lipolytic and insulinotropic effects and synergizes with GLP-1 to enhance insulin secretion. Methods: Human visceral adipocytes were treated with CRRL191 (10 -8 -10 -6 M) for 6 hrs. Lipolysis was assessed by measuring glycerol and non-esterified fatty acids (NEFA) in supernatants. Rat pancreatic beta cells (INS-1) were stimulated treated with CRRL191 (10 -10 -10 -6 M), GLP-1 (10 -10 -10 -6 M) alone or their combination for 1 hr. Insulin secretion was quantified by ELISA. Results: CRRL191 stimulated lipolysis in human visceral adipocytes (10 -8 -10 -6 M), increasing glycerol and NEFA release. CRRL191 induced greater glycerol release than GLP-1 across all tested doses, with low dose CRRL191 (10 -10 M) notably enhancing NEFA production. In INS-1 cells, CRRL191 dose dependently increased insulin secretion under hyperglycemic conditions, demonstrating superior potency at lower concentrations (10 -10 and 10 -8 M) compared to GLP-1. Remarkably, co-administration of CRRL191 with GLP-1 amplified insulin release beyond levels achieved by either peptide alone. Conclusion: CRRL191 is a potent GC-A agonist that robustly stimulates lipolysis in visceral adipocytes and enhances insulin secretion in pancreatic beta cells. Its synergistic interaction with GLP-1 highlights a novel therapeutic avenue targeting the GC-A/cGMP pathway for integrated treatment of cardiometabolic diseases. These findings support further evaluation of CRRL191 as a promising candidate for cardiometabolic drug development.

BACKGROUND: Cardiomyocyte oxidative stress significantly contributes to the progression of hypertension-induced heart failure, highlighting the need for targeted therapies. We developed a novel peptide, NPA7, that coactivates the GC-A (guanylyl cyclase A)/cGMP and MasR (Mas receptor)/cAMP pathway. This study aimed to test NPA7’s ability to inhibit oxidative stress by modulating the p62 (Sequestosome 1)-KEAP1 (Kelch-like ECH-associated protein 1)-NRF2 (nuclear factor erythroid 2-related factor 2) pathway in human cardiomyocytes (HCMs) and a rat model of hypertension. METHODS: Oxidative stress was induced in HCMs using H 2 O 2 with phosphate-buffered saline or NPA7 treatment. Intracellular reactive oxygen species levels were assessed via dihydroethidium staining. Western blotting analysis measured p62, KEAP1, and NRF2 protein levels, while GSH/GSSG (glutathione/glutathione disulfide) ratios and antioxidant gene expression were analyzed. HCMs were transfected with small interfering RNA targeting GC-A, MasR, or p62 before NPA7 and H 2 O 2 treatment. In vivo, spontaneously hypertensive rats received saline or NPA7, with normotensive Wistar Kyoto rats as control and cardiac oxidative stress, KEAP1 protein levels, NOX2 (NADPH oxidase 2), and p67 (NADPH oxidase subunit p67-phox) mRNA levels were measured. RESULTS: NPA7 reduced H 2 O 2 -induced reactive oxygen species levels and increased GSH/GSSG ratio in HCMs. Silencing GC-A (guanylyl cyclase A receptor) and MasR (Mas receptor) reversed NPA7’s effects. NPA7 activated the KEAP1-NRF2 pathway, enhancing NRF2’s antioxidant target gene expression. In p62 knockdown HCMs, NPA7-induced KEAP1 degradation and NRF2 activation were diminished. Reactive oxygen species levels were elevated in spontaneously hypertensive rat versusWistar Kyoto rats’ hearts, however, NPA7 treatment reduced myocardial reactive oxygen species, suppressed KEAP1 protein, and decreased NOX2 and p67 mRNA levels. CONCLUSIONS: NPA7 exhibits antioxidant properties in HCMs and spontaneously hypertensive rat hearts by targeting GC-A and MasR through the p62-KEAP1-NRF2 pathway, supporting a novel therapeutic approach against cardiovascular disease–related oxidative stress.

Background and Objective: Decline of cardiovascular (CV) function is commonly observed in patients with severe acute pancreatitis (AP), which is associated with high mortality and morbidity. While the pathological changes in the pancreas during severe AP have been extensively studied, the impact on the CV system has not been well characterized. Furthermore, obesity is a major risk factor for severe AP. Hereby we utilized an obesity-associated mouse AP model to assess potential alterations in vascular integrity and cardiac function, two major components of circulatory failure. Methods: Wild-type male C57BL6J mice were fed a normal or a high fat (to induce obesity) diet. Both groups received intraperitoneal injection of cerulein (100 mg/kg/h x12) to induce AP. H&E and TUNEL staining of pancreas were performed to assess histology and cell death. To measure vascular integrity, we measured the leakiness of a fluorescein-conjugated dextran (70 kDa) in tissue parenchyma and serum levels of soluble vascular endothelial (VE)-cadherin, which has recently shown to be shed from endothelial cells with disrupted adherens junctions. Cardiac systolic and diastolic function were assessed by echocardiography at baseline and post-AP induction. Results: Compared to lean mice, obese mice developed more severe pancreatic edema, cell death and inflammatory cell infiltration, along with significantly increased accumulation of fluorescent dextran in multiple organs including pancreas, heart, lung, and kidney, suggesting systemic disruption of vascular integrity. Increased serum levels of soluble VE-cadherin in obese mice (vs. lean) after AP induction further supported compromised endothelial cell barrier function. At baseline, obese mice exhibited similar cardiac function to lean mice. However, obese mice, but not lean mice, developed impaired systolic and diastolic function post-AP induction, as supported by decreased ejection fraction and e’ velocity respectively. Conclusion: In this obesity-associated severe AP mouse model, systemic vascular permeability is increased, and cardiac function is substantially compromised. Systemic vascular hyperpermeability and cardiac dysfunction may represent therapeutic targets to enhance the outcomes in severe AP.

Background: Tyrosine kinase inhibitors (TKIs), such as sunitinib, are highly effective in treating cancers. However, they have severe cardiovascular (CV) side effects that include cardiotoxicity via cardiomyocyte injury and death resulting in myocardial dysfunction. There are no FDA-approved drugs to prevent or treat cardiotoxicity, which have been linked mechanistically to mitochondrial dysfunction and oxidative stress, highlighting the need for new therapeutics. Two recognized CV protective pathways are the particulate guanylyl cyclase A receptor (GC-A)/cGMP and the Mas receptor (MasR)/cAMP pathways. We recently engineered NPA7 a novel peptide that activates both pathways. Aim: Here we investigated NPA7’s ability to protect against sunitinib-induced cardiotoxicity in human cardiomyocytes (HCMs) and defined its role on mitochondrial function. Methods: HCMs were treated with DMSO or sunitinib (10 µM) together with PBS or NPA7 (10 µM). Intracellular reactive oxygen species (ROS) was assessed by DHE staining. CCK8 assay was performed to measure cell viability. TOM20 staining were performed by immunofluorescence and the mitochondrial length was analyzed. The protein levels of mitochondrial dynamics markers (fission: MFF, Fis1; fusion: OPA1 and MFN1) proteins were measured by western blot. Cell surface area was assessed by phalloidin staining with mRNA levels of hypertrophic gene markers (NPPA and MYH7) in HCMs using real-time PCR. Results: Sunitinib increased DHE staining and intracellular ROS in HCMs, which was decreased with NPA7 treatment. NPA7 enhanced HCM cell viability in the presence of sunitinib. TOM20 staining showed a marked reduction in mitochondrial length in sunitinib group, compared to DMSO group, whereas NPA7 treatment rescued mitochondria length (DMSO= 6.15 ± 0.94 μm, Sunitinib= 2.42 ± 0.63 μm, NPA7= 5.4 ± 1.19 μm; P < 0.05). Moreover, NPA7 inhibited mitochondrial fission protein levels (MFF and Fis1) and increased mitochondrial fusion protein levels (OPA1, MFN1) in HCMs treated with sunitinib. Sunitinib treatment notably increased HCM cell surface area and hypertrophic gene markers (NPPA and MYH7), whereas NPA7 abolished these markers of hypertrophy. Conclusions: We report, for the first time, that NPA7 protects against sunitinib induced oxidative stress, mitochondrial fragmentation, hypertrophy and cell death in HCMs. These data support a novel therapeutic approach against TKI-induced cardiotoxicity with NPA7 to which no therapies exist.

BACKGROUND: Atrial natriuretic peptide (ANP) and glucagon-like peptide-1 (GLP-1) are endogenous hormones known for roles in cardiovascular regulation and metabolic homeostasis. ANP mediates its actions via the GC-A receptor, while GLP-1 via the GLP-1 receptor (GLP-1R). Both peptides may stimulate insulin secretion from pancreatic beta cells and augment lipid metabolism in adipocytes, yet potential synergistic effects remain unexplored. To optimize ANP activation of GC-A, we developed a novel 15 amino acid miniaturized GC-A activating peptide CRRL555. CRRL555 possesses greater GC-A binding and activating properties than ANP. AIMS: We investigated the metabolic properties of CRRL555/GC-A and its interaction with GLP-1/GLP-1R in vitro. METHODS: Rat pancreatic beta cells (INS-1) were stimulated with high glucose (20mM) and treated with GLP-1 or CRRL555 (10 -10 -10 -6 M) and together for 1 hr. Supernatant was collected and insulin was measured by ELISA. Human visceral adipocytes were differentiated for 10 days and then treated with GLP-1 or CRRL555 (10 -10 -10 -6 M) or together for 6 hrs. Supernatant was collected and glycerol and free fatty acid (NEFA), indicators of lipolysis, were measured. RESULTS: CRRL555 (p<0.05) and GLP-1 (p<0.05), dose dependently, stimulated insulin secretion in INS-1 cells in the presence of high glucose. Importantly, CRRL555 combined with GLP-1, resulted in a greater enhancement (p<0.05) of insulin secretion compared to either peptide alone. While high dose CRRL555 and GLP-1 (10 -6 M) stimulated lipolysis in visceral adipocytes with increases in glycerol and NEFA, only CRRL555 at low dose (10 -10 M), and not low dose GLP-1 (10 -10 M), stimulated glycerol and NEFA production (p<0.05). When low dose GLP-1 (10 -10 M) was added to low dose CRRL555(10 -10 M), lipolysis was like CRRL555 alone. CONCLUSION: We report a novel synergy in insulin release from beta cells with combined stimulation of the potent and miniaturized GC-A designer peptide CRRL555 with GLP-1. CRRL555 possesses greater lipolytic properties compared to GLP-1 in visceral adipocytes at low doses advancing novel metabolic actions of CRRL555 alone or combined with GLP-1R activation. These in vitro studies of dual receptor activation of GC-A and GLP-1R highlight the therapeutic potential of combining CRRL555 with GLP-1-based therapies for the treatment of cardiometabolic diseases, thus supporting studies of dual GC-A/GLP-1R activation in experimental cardiometabolic disease states.

Abstract Background/Introduction MANP is a novel atrial natriuretic peptide (ANP) analog bioengineered as a particulate guanylyl cyclase A receptor (GC-A) activator with superior receptor binding, resistance to neprilysin degradation, natriuretic, aldosterone suppressing and blood pressure (BP) lowering properties than native ANP. MANP is now under clinical development for resistant hypertension (RH). The rationale for its design was the fundamental role of the ANP/GC-A system in BP homeostasis through which GC-A activation with MANP leads to BP reduction through renal, vascular, and hormonal mechanisms mediated by the second messenger cGMP. Purpose We investigated the safety, tolerability, cGMP activation and BP reductions of MANP compared to placebo in subjects with RH. Methods We performed a double-blind, placebo controlled randomized trial in 36 RH patients comprised of approximately 50% non-African Americans (NAA) and 50% AA. MANP was administered in 6 cohorts receiving ascending subcutaneous (SQ) doses of MANP once daily from 3 ug/kg to a maximal dose of 7 ug/kg or placebo for 5 days and then followed for 21 days after dosing. Endpoints included safety, cGMP activation and changes in systolic BP (SBP), aldosterone (Aldo) levels and glomerular filtration rate (GFR). Results MANP was safe and well tolerated. One patient in the 7 ug/kg cohort was discontinued due to symptomatic hypotension. Compared to baseline, plasma cGMP increased in all MANP groups on Day 1 and Day 5 with no change in the placebo group. The maximal SBP reduction in the MANP group on Days 1 (D1) and 5 (D5) was -17.5 (D1) and -16 mmHg (D5) with 3 ug/kg (lowest dose) and -39.5 (D1) and -36.3 mmHg (D5) with 7 ug/kg (highest dose); Changes in the Placebo group were -6.3 (D1) and -16.7 mmHg (D5). Notably, the SBP reductions in AA were greater than NAA in the 4 and 7 ug/kg cohorts. After the 1-hour timepoint on both the first and fifth days, Aldo and percentage of Aldo reduction generally remained suppressed compared to baseline. Twenty-one days after MANP dosing, SBP remained lower in three groups receiving SQ MANP (4, 4.5 and 7 ug/kg) compared to placebo in association with a preservation of GFR. There were no reported drug related serious adverse events. Conclusions This clinical trial demonstrates that once a day SQ administration of MANP in RH subjects activates cGMP, without attenuation over 5 days, and reduces SBP and preserves GFR. At higher doses of MANP, SBP reductions were greater in AA compared to NAA. MANP also demonstrated Aldo inhibiting actions compared to placebo. Importantly, MANP was overall safe and well-tolerated. Our findings support the continued clinical development of MANP as a novel GC-A activating peptide for the treatment of RH.

Abstract Myocardial fibrosis is a pathological hallmark of cardiovascular disease (CVD), and excessive fibrosis can lead to new-onset heart failure and increased mortality. Currently, pharmacological therapies for myocardial fibrosis are limited, highlighting the need for novel therapeutic approaches. The particulate guanylyl cyclase B (GC-B) receptor possesses beneficial antifibrotic actions through the binding of its natural ligand C-type natriuretic peptide (CNP) and the generation of the intracellular second messenger, cyclic guanosine 3′,5′-monophosphate (cGMP). These actions include the suppression of fibroblast proliferation and reduction in collagen synthesis. With its abundant expression on fibroblasts, the GC-B receptor has emerged as a key molecular target for innovative CVD therapeutics. However, small molecules that can bind and potentiate the GC-B/cGMP pathway have yet to be discovered. From a cell-based high-throughput screening initiative of the NIH Molecular Libraries Small Molecule Repository and hit-to-lead evolution based on a series of structure–activity relationships, we report the successful discovery of MCUF-42, a GC-B-targeted small molecule that acts as a positive allosteric modulator (PAM). Studies herein support MCUF-42's ability to enhance the binding affinity between GC-B and CNP. Moreover, MCUF-42 potentiated cGMP levels induced by CNP in human cardiac fibroblasts (HCFs) and notably also enhanced the inhibitory effect of CNP on HCF proliferation. Together, our findings highlight that MCUF-42 is a small molecule that can modulate the GC-B/cGMP signaling pathway, potentially enhancing the antifibrotic actions of CNP. Thus, these data underscore the continued development of GC-B small molecule PAMs as a novel therapeutic strategy for targeting cardiac fibrosis and CVD.