<h3>Introduction</h3> Therapeutic strategies harnessing both renin-angiotensin system (RAS) and natriuretic peptide system (NPS) mediated effects, such as Sacubitril/Valsartan, has been proven to be promising in treating human heart failure (HF). However, molecular understanding of the interaction between RAS and NPS remains to be fully elucidated. While angiotensin II (ANGII), the central RAS hormone, is thought to interact with NPS at multiple levels, whether and how it may influence the actions of particulate guanylyl cyclase A (pGC-A), the only functional receptor for both atrial and b-type natriuretic peptide (ANP and BNP), has not been investigated. <h3>Hypothesis</h3> We hypothesize that ANGII naturally suppresses pGC-A and the inhibition of this crosstalk would be a novel therapeutic strategy to combat cardiovascular disease (CVD) of which RAS hyperactivation is a hallmark feature. <h3>Methods</h3> Plasma ANP, BNP, cGMP, and ANGII were measured in 128 healthy humans to define the balance between ANGII and NPS. cGMP responses to acute infusion of ANP alone and in the presence of ANGII was characterized in normal rats. The molecular mechanisms including involvement of ANGII type I receptor (AT1R) and its downstream target protein kinase C (PKC) were investigated in HEK293 cell overexpressing pGC-A and together with AT1R. CRRL-58, an innovative dual-functional peptide was designed to activate pGC-A and inhibit PKC, and tested for cGMP generation in HEK293 cells. <h3>Results</h3> In healthy human, plasma cGMP was positively associated with ANP or BNP only in low (≤ 4.5 pg/mL) but not those with high (> 4.5 pg/mL) ANGII levels (see Figure). Infusion of ANP (300 pmol/kg/min) in normal rats increased plasma and urinary cGMP, however ANP mediated cGMP generation was reduced in the presence of ANGII (50 pmol/kg/min). Notably, the suppressive effect of ANGII on pGC-A was recapitulated in HEK293 cell overexpressing both pGC-A and AT1R, but not in HEK293 cell overexpressing pGC-A alone. Meanwhile, we found PKC, a well-established downstream target of AT1R, was a key mediator for this observed crosstalk, as the suppression effect of ANGII was largely ablated by Go6983, a pan PKC inhibitor. Notably, CRRL-58 had superior potency in cGMP generation compared to the currently best-in-class ANP-analog, MANP, in vitro. <h3>Conclusions</h3> Our human and experimental data demonstrate that ANGII is a natural suppressor of pGC-A activation via AT1R and PKC signaling, but not via pGC-A per se. Moreover, we report for the first time that CRRL-58, an innovative bioengineered peptide that activates pGC-A receptor while inhibiting PKC signaling, potently generates cGMP. Together, our study provides new insights into the interaction between RAS and NPS, and highlights a novel and mechanism-based therapeutic avenue for treating HF and other CVDs.