Moroni, Dante

Background: Heart failure (HF) is a complex syndrome marked by adverse cardiac remodeling and natriuretic peptide (NP) deficiency, which drives disease progression despite current therapies. NPs exert cardioprotective effects via particulate guanylate cyclase receptors GC-A and GC-B, which generate cGMP. Activation of GC-A by ANP or BNP induces arteriodilation, natriuresis, antihypertrophic effects, and inhibits the renin-angiotensin-aldosterone system, while GC-B activation by CNP mediates antifibrotic, lusitropic, venodilatory, and anti-inflammatory actions. Existing drugs target either GC-A or GC-B, but none target both. We developed RT-A1, a unimolecular peptide activating both GC-A and GC-B, hypothesizing it will attenuate myocardial remodeling in a preclinical model of HF with preserved systolic function. Methods: RT-A1 was engineered by rational drug design. HEK293 cells expressing human GC-A or GC-B, human cardiac myocytes (CMs) and fibroblasts (CFs) were treated with RT-A1 (10-100nM) and cGMP was measured. In vivo, mice underwent mild transverse aortic constriction (TAC) or sham surgery. After 3 weeks, LV hypertrophy (LVH) was confirmed by echo. TAC mice were then randomized to vehicle (Veh) or RT-A1 (50pmol/kg/min) via subcutaneous osmotic pumps for 3 weeks. Endpoints included LV/body weight ratio, myocyte cross-sectional area (CSA), plasma cGMP, and RNA-seq. Data are mean±SEM. P<0.05 was significant. Results: RT-A1 dose-dependently increased cGMP in HEK293 cells expressing GC-A or GC-B, confirming dual activation, and elevated cGMP in human CMs and CFs. TAC induced significant LV wall thickening with preserved systolic function versus sham. After three weeks, RT-A1 normalized LV/body weight (3.14±0.14 vs. 3.82±0.29, P=0.03) and reduced myocyte CSA (348±16 vs. 506±17, P=0.0005) compared to Veh. Plasma cGMP was higher in TAC+RT-A1 versus TAC+Veh (85±8 vs 54±8 pmol/ml, P=0.01), confirming target engagement. RNA-seq showed reduced LV BNP expression and downregulation of hypertrophy, fibrosis, and inflammation pathways with RT-A1 treatment vs. Veh following TAC. Conclusions: RT-A1 is a novel dual GC-A/GC-B peptide activator that elevates plasma cGMP and reduces adverse cardiac remodeling in experimental HF by downregulating hypertrophy, fibrosis, and inflammation pathways. Dual GC-A/GC-B activation via RT-A1 represents a promising anti-remodeling therapeutic strategy for HF with preserved systolic function warranting further study.

Background: Diabetic cardiomyopathy is a common complication of diabetes, which can progress to symptomatic heart failure. Current conventional medical therapy does not reverse the deleterious features of diabetic cardiomyopathy. The natriuretic peptide-cGMP system has been proven to provide a cardioprotective role in diabetic rats. Therefore, we developed CRRL094, a n bispecific peptide that simultaneously activates the natriuretic peptide system and glucagon-like peptide-1 (GLP-1) receptor. In this study, we aimed to characterize the cardioprotective role of CRRL094 and elucidate its downstream molecular mechanisms. Methods: In vitro, human cardiomyocytes (HCMs) were pretreated with PBS or CRRL094 (5 µM) for 6 hours, then exposed to high glucose treatment (HGT, 25 mM) for 48 hours. HCM hypertrophy was determined by assessing mRNA levels of hypertrophic gene markers (NPPA and NPPB) using real-time PCR. Lipid droplet staining was performed using BODIPY 493/503 dye and fluorescence images were analyzed. The protein levels of CIDEC (lipid droplet-related gene) and phosphorylation-AMPK and total AMPK (a key regulator of lipid metabolism) were analyzed by Western blot. In vivo, a type 2 diabetes (DM2) rat model was established by low-dose intraperitoneal Streptozotocin (STZ) injection and a high-fat diet in Wistar rats (male, 4- to 6-week-old). Diabetes was confirmed by fasting blood glucose > 350 mg/dL. Rats were then allocated to two groups: saline-treated controls (n=6) or CRRL094-treated (30 pmol/kg/min; n=6), with treatment delivered via osmotic pumps for 28 days. Heart tissues were collected and analyzed. Results: HGT in HCMs significantly increased the mRNA levels of NPPA and NPPB, whereas CRRL094 significantly attenuated markers of hypertrophy. Further, HGT increased lipid accumulation in HCMs, which was decreased with CRRL094 treatment. Moreover, CRRL094 increased p-AMPK protein levels and decreased CIDEC protein levels in HCMs under HGT. In a DM2 rat model, chronic CRRL094 therapy was associated with suppression of NPPA and NPPB, downregulation of CIDEC, and upregulation of p-AMPK expression in the heart tissue. Conclusion: CRRL094 protects against HGT-induced hypertrophy and inhibits lipid accumulation through regulating the AMPK/CIDEC pathway in vitro and in vivo . These findings support CRRL094 as a novel therapeutic candidate to prevent diabetic cardiomyopathy.

Introduction: Diabetes mellitus (DM) is strongly associated with metabolic and cardiorenal derangements. Natriuretic peptides (NPs), and glucagon-like peptide 1 receptor agonists (GLP-1 RA) have well-established cardiometabolic and cardiorenal protective effects. We developed a novel bispecific biologic, CRRL 101, which agonizes guanylyl cyclase A (GCA) NP receptors and GLP-1 receptors. In this study, we sought to evaluate the in vitro effects and in vivo impact of CRRL 101 in a DM rat model. Methods: In vitro experiments evaluated the impact of CRRL 101 treatment of GCA receptor transfected human embryonic kidney (HEK) cells and INS-1 rat pancreatic beta cells. In vivo experiments were conducted by inducing DM in Wistar rats (male, 6-8-week-old) by intraperitoneal Streptozotocin (STZ) injection (65 mg/kg). One week after STZ injection, DM was confirmed (fasting blood glucose > 350 mg/dL). Rats were then divided into 3 groups: saline control (n=6), 1 pmol/kg/min CRRL-101 (“1pmol” n= 4), and 10 pmol/kg/min CRRL-101 (“10 pmol” n=5). Treatment was infused for 120 min after which rat blood and urine were collected. Data were analyzed using GraphPad Prism 10.0.0. Results: In vitro, there was a marked increase in cyclic GMP (cGMP) levels (pmol/mL) in HEK treated with 10 -6 M CRRL 101 (mean difference ± SEM:1.603 ± 0.29 p = 0.0048). In INS-1 cells treated with CRRL 101 at 10 -6 M in a 20 mM glucose medium, cAMP levels (pmol/mL) markedly increased (16.7 ± 1.47 vs 23.19 ± 1.51 p=0.0036) and insulin levels (ng/mL) doubled (4.4 ng/mL ± 0.44 vs 9.5 ng/mL ± 0.34 in 20 mM glucose p < 0.0001). Similar increases were observed at lower doses (10 -7 M, 10 -8 M) of CRRL 101. In vivo , after 120 minutes of treatment, mean plasma cGMP levels were 6.5x greater in both groups (mean difference± SEM) (1pmol: 38.89 ± 7.93, p = 0.016; 10pmol: 39.40 ± 4.84 p=0.001). Plasma insulin (ng/mL) more than doubled with both doses (1pmol: 0.39 ± 0.148, p = 0.039; 10 pmol: 0.198 ± 0.051, p = 0.004) with no significant increase with placebo ( 0.03 ± 0.08, p = 0.67). Rate of natriuresis (mEq/min) more than doubled with peptide administration vs placebo (1 pmol: 0.36 ± 0.093 p = 0.014; 10 pmol: 0.38 ± 0.13, p = 0.034). Conclusions: Our novel bispecific biologic, CRRL 101, activates GC-A, increasing plasma cGMP and inducing natriuresis, and stimulates GLP-1R, raising cAMP and plasma insulin. Chronic administration studies to eludicate its therapeutic efficacy are warranted.

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: 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 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.

Introduction: Excess cardiomyocyte oxidative stress is a major metabolic abnormality in HTN and its progression to HF. Thus, therapies that reduce oxidative stress in the heart may lead to a reduction in CVD related adverse outcomes such as HF and death. Recently, we bioengineered a bispecific peptide NPA7 that co-activates the protective GC-A/cGMP and MasR/cAMP pathways. Previously we showed that NPA7 possesses cardiorenal protective properties. However, the antioxidant effects of NPA7 within the heart is unknown. Hypothesis: NPA7 protects human cardiomyocytes against oxidative stress through the GC-A/Mas Receptor-KEAP1-NRF2 pathway. Methods: HCMs were pretreated with PBS or NPA7 (10 uM) followed by 400 uM hydrogen peroxide (H2O2) to induce oxidative stress. Intracellular ROS was measured by dihydroethidium (DHE) staining and protein levels of KEAP1 and NRF2 via western blot. The ratio of GSH/GSSG were determined by using commercial kit. mRNA levels of G6PD, GCLC, GCLM and GSS in HCMs, which represents antioxidant capacity, were determined by real-time PCR. For knockdown experiments, HCMs were transfected with the siRNA target GC-A and MasR for 24 h and then treated with NPA7 and H2O2 for another 20 h. Results: H2O2 increased DHE staining level, which indicated elevated intracellular ROS levels within HCMs. Notably, treatment with NPA7 decreased DHE level and increased the ratio of GSH/GSSG in HCMs with H2O2. Furthermore, NPA7 significantly increased the mRNA level of NRF2 target genes (G6PD, GCLC, GCLM, GSS) through NRF2 activation and KEAP1 degradation, indicating that NPA7 activates KEAP1-NRF2 pathway, the upstream pathway that regulate antioxidant gene expression, in HCMs. Moreover, these effects were eliminated if GC-A and MasR were silenced by siRNA, thus supporting the protective antioxidant role of both GC-A and MasR. Conclusions: The present study establishes an antioxidant action of NPA7, a novel bispecific designer peptide, on H2O2-induced oxidative stress by the dual targeting of GC-A and MasR through the KEAP1-NRF2 signaling pathway in HCMs. These results advance NPA7 as an innovative therapeutic strategy targeting oxidative stress related to CVD.

Introduction: Atrial natriuretic peptide (ANP) is the most potent endogenous activator of the guanylyl cyclase A receptor (GC-A) mediating cardiorenal protective actions by increasing cGMP production. To test the hypothesis that acute decompensated heart failure (ADHF) is associated with increased circulating ANP but with reduced GC-A potency, we developed an ex-vivo precision medicine assay to quantify the potency of circulating ANP in plasma from healthy and ADHF subjects. Further, we assessed the ex-vivo potency of MANP, a novel ANP analog with greater cGMP activation than ANP, also using plasma of healthy and ADHF subjects. Methods: For the potency assay, we engineered HEK293 cells to overexpress human GC-A. Plasma from individual healthy (n=4) and ADHF (n=4) subjects was incubated in the assay and cGMP was assessed. The endogenous ANP derived cGMP was evaluated against the cGMP response of equimolar synthetic ANP (S ANP ) to assess potency of ANP from each cohort. MANP mediated cGMP generation was also assessed in the assay using healthy and ADHF plasma. Results: Healthy plasma, in which plasma ANP was 26±5 pg/mL, generated 10.3±0.7 pmol/mL of cGMP. S ANP added to the assay to mimic endogenous ANP levels in healthy subjects produced 7.8±0.5 pmol/mL of cGMP. ADHF plasma with markedly elevated ANP (350±57pg/mL) generated 23.5±3.1 pmol/mL of cGMP. S ANP mimicking plasma ANP in ADHF produced 59.7±13.8 pmol/mL of cGMP, which was greater than cGMP generated from ADHF patient-derived plasma (p<0.05), consistent with reduced potency of endogenous ANP in ADHF. Low treatment dose of MANP (LD MANP ; 10 -8 M) in healthy plasma increased cGMP to 45±5.5 pmol/ml while high treatment dose (HD MANP ; 10 -6 M) increased cGMP to 167.1±14.1 pmol/mL. In markedly elevated ANP ADHF plasma, LD MANP increased cGMP to 60.4±9.7 pmol/mL while HD MANP increased cGMP to 200.8±5.4 pmol/mL (p<0.03 for both) demonstrating similar cGMP production by MANP in healthy and ADHF plasma. Conclusions: Employing a novel ex-vivo precision medicine ANP/GC-A/cGMP assay, we conclude that ADHF is characterized by elevated ANP yet with impaired potency in GC-A activation and cGMP generation. MANP overcomes this impairment and serves as a potential efficacious GC-A activating therapeutic in heart failure.

Introduction: Hypertension (HTN) represents one of the greatest burdens in human health and is associated with increased morbidity and mortality. Despite the availability of several antihypertensive drugs, most patients have suboptimal blood pressure (BP) control, thus underscoring the need for new therapeutic drugs. The natriuretic peptide receptor A (NPRA) possesses potent vasodilating, natriuretic and diuretic actions via activation by ANP or BNP and generation of its second messenger, cGMP. Recently, we reported the discovery of a small molecule positive allosteric modulator (PAM) for NPRA, MCUF-651, which enhances the ANP/BNP/NPRA/cGMP pathway (PNAS,2021). To date, the in vivo actions of MCUF-651 remains unknown. Here we tested the hypothesis that MCUF-651 would have BP lowering and renal enhancing properties in experimental HTN. Methods: A single IV bolus of MCUF-651 (10mg/kg; n=4) or vehicle (V; n=5) was injected into anesthetized spontaneous hypertensive rats (SHRs). Plasma and urinary cGMP (PcGMP and UcGMP), mean arterial pressure (MAP) and urinary volume (UV) and sodium (UNa) excretion were assessed at baseline (BL) and over 60-mins post-bolus. Results: In SHRs, PcGMP and UcGMP were significantly elevated with MCUF-651 compared to the vehicle group (ΔPcGMP MCUF-651: 16±5, ΔPcGMP V: -2±3, pmol/mL; P =0.003; ΔUcGMP MCUF-651: 78±29, ΔUcGMP V: 30±8, pmol/min, P =0.01), thus supporting NPRA target engagement. Notably, the elevations in cGMP with MCUF-651 were associated with a significant reduction in MAP at 15-mins post bolus compared to vehicle (ΔMAP MCUF-651: -29±14, ΔMAP V: -6±2 mmHg; P =0.04) and this MAP reduction was sustained over 60 mins. Further, UV and UNa excretion were significantly increased, from BL, with MCUF-651 (BL UV: 6 ± 2, 60 mins post bolus UV: 56± 18 μL/min, P <0.001; BL UNa: 1±0.2, 60 mins post bolus UNa: 8±2 μmol/min, P <0.001). Conclusions: We report for the first time that MCUF-651, a novel NPRA small molecule PAM, engages NPRA, increases cGMP and reduces MAP while enhancing sodium and water excretion in experimental HTN. These findings support the development of MCUF-651 as a potential new therapeutic modality to optimize BP lowering goals and reduce adverse outcomes in human HTN.