Depletion of cyclic-GMP levels and inhibition of cGMP-dependent protein kinase activate p21Cip1 /p27Kip1 pathways and lead to renal fibrosis and dysfunction.

Cell-cycle regulatory proteins (p21Cip1 /p27Kip1 ) inhibit cyclin and cyclin-dependent kinase (CDK) complex that promotes fibrosis and hypertrophy. The present study examined the role of CDK blockers, p21Cip1 /p27Kip1 in the progression of renal fibrosis and dysfunction using Npr1 (encoding guanylyl cyclase/natriuretic peptide receptor-A, GC-A/NPRA) gene-knockout (0-copy; Npr1-/- ), 2-copy (Npr1+/+ ), and 4-copy (Npr1++/++ ) mice treated with GC inhibitor, A71915 and cGMP-dependent protein kinase (cGK) inhibitor, (Rp-8-Br-cGMPS). A significant decrease in renal cGMP levels and cGK activity was observed in 0-copy mice and A71915- and Rp-treated 2-copy and 4-copy mice compared with controls. An increased phosphorylation of Erk1/2, p38, p21Cip1 , and p27Kip1 occurred in 0-copy and A71915-treated 2-copy and 4-copy mice, while Rp treatment caused minimal changes than controls. Pro-inflammatory (TNF-α, IL-6) and pro-fibrotic (TGF-ß1) cytokines were significantly increased in plasma and kidneys of 0-copy and A71915-treated 2-copy mice, but to lesser extent in 4-copy mice. Progressive renal pathologies, including fibrosis, mesangial matrix expansion, and tubular hypertrophy were observed in 0-copy and A71915-treated 2-copy and 4-copy mice, but minimally occurred in Rp-treated mice compared with controls. These results indicate that Npr1 has pivotal roles in inhibiting renal fibrosis and hypertrophy and exerts protective effects involving cGMP/cGK axis by repressing CDK blockers p21Cip1 and p27Kip1 .

Physician Satisfaction with Anti-Inflammatory Topical Medications for the Treatment of Dry Eye Disease.

PURPOSE: Dry eye disease (DED) is one of the most common ophthalmic disorders. Pathogenesis of the disease includes inflammation of the ocular surface and lacrimal gland. Two anti-inflammatory prescription treatments are currently available: cyclosporine ophthalmic emulsion 0.05% (CYC) and lifitegrast 5% ophthalmic solution (LIF). The objective of this survey-based study was to assess physician satisfaction with CYC and LIF for the treatment of DED. METHODS: Physicians currently treating DED patients with CYC or LIF were asked to rate the experiences of their patients currently or formerly using CYC and LIF, and their own perspectives on the two treatments. RESULTS: Twenty-one physicians participated in the survey, providing responses on behalf of 210 patients. Overall, physicians reported low levels of satisfaction with onset of action of CYC and LIF, and fewer than half considered either drug to be effective in managing symptoms or improving patient quality of life (QoL). Burning sensation and dysgeusia were the most frequently reported side effects. Onset of action and effectiveness after onset were the main switching drivers. Although two-thirds of physicians were satisfied with the overall effectiveness of CYC and LIF, all physicians agreed that more DED treatment options are needed, with >50% strongly agreeing. CONCLUSION: Physicians perceived a gap in DED management with currently available topical anti-inflammatory agents. Although satisfaction with CYC and LIF was high, few physicians considered these medications to be effective in managing symptoms or improving QoL.

Treatment Satisfaction Among Patients Using Anti-Inflammatory Topical Medications for Dry Eye Disease.

PURPOSE: To assess patient satisfaction among current and former users of the anti-inflammatory topical medications, cyclosporine A 0.05% (CYC) and lifitegrast 5.0% (LIF), for the management of dry eye disease (DED). PATIENTS AND METHODS: Patients with DED were recruited via physician referral to participate in a survey. Current users of CYC or LIF were asked to rate their experience in terms of satisfaction, side effects, and limitation of activities. Switchers of CYC to LIF or LIF to CYC were asked to rate the importance of potential reasons for switching. RESULTS: Surveys were completed by 207 patients currently treated with CYC (n=98), LIF (n=96), or other DED medications (n=13). Although overall satisfaction with current treatment was high, current users of CYC and LIF reported ineffective relief of DED symptoms (31% and 22%, respectively) and dissatisfaction with the time to onset of effect (29% and 11%). Substantial proportions of patients reported 'sometimes', "usually", or 'always' experiencing the following side effects: burning sensation (72% CYC, 64% LIF), itching (43% CYC, 44% LIF), altered sensation of taste (21% CYC, 56% LIF), blurred vision (37% CYC, 50% LIF), and discharge (28% CYC, 30% LIF). Of the 30 switchers of CYC to LIF and 31 switchers of LIF to CYC, the majority reported inability to relieve DED symptoms as a very or extremely important switching reason. Despite switching, one in four patients were somewhat dissatisfied or dissatisfied with their current medication, with 37% of patients reporting ineffective symptom relief. CONCLUSION: Although the rate of overall satisfaction was generally high with both LIF and CYC, many patients were unable to achieve effective symptom relief and commonly experienced side effects. The proportion of patients who were dissatisfied and/or unable to achieve effective symptom relief even after switching suggests the need for additional treatment options for managing DED.

Genetic disruption of guanylyl cyclase/natriuretic peptide receptor-A upregulates renal (pro) renin receptor expression in Npr1 null mutant mice.

The objective of the present study was to determine whether targeted-disruption of Npr1 gene (encoding for guanylyl cyclase/natriuretic peptide receptor-A; GC-A/NPRA) upregulates pro(renin) receptor (P)RR expression and leads to the activation of MAPKs in Npr1 gene-knockout mice. The Npr1 homozygous (Npr1-/-; 0-copy), heterozygous (Npr1+/-; 1-copy), wild-type (Npr1+/+; 2-copy), and gene-duplicated (Npr1++/++; 4-copy) mice were utilized. To identify the canonical pathway of (P)RR, we administered ACE-1 inhibitor (captopril), AT1R blocker (losartan), and MAPKs inhibitors (U0126 and SB203580) to all Npr1 mice genotypes. The renal expression of (P)RR mRNA was increased by 3-fold in 0-copy mice and 2-fold in 1-copy mice compared with 2-copy mice, which was also associated with significantly increased expression of ACE-1 and AT1R mRNA levels. Similarly, the phosphorylation of MAPKs (Erk1/2 and p-p38) was enhanced by 3.5-fold and 3.2-fold, respectively, in 0-copy mice with significant increases in 1-copy mice compared with 2-copy mice. The kidney and plasma levels of proinflammatory cytokines were significantly elevated in 0-copy and 1-copy mice. Treatment with captopril and losartan did not alter the expression of (P)RR in any of the Npr1 mice genotypes. Interestingly, losartan significantly reduced the phosphorylation of Erk1/2 and p38 in Npr1 mice. The present results suggest that the ablation of Npr1 upregulates (P)RR, MAPKs (Erk1/2 and p38), and proinflammatory cytokines in 0-copy and 1-copy mice. In contrast, the duplication of Npr1 exhibits the anti-inflammatory and antihypertensive effects by reducing the activation of MAPKs and inhibiting the expression levels of RAAS components and proinflammatory cytokines.

Retinoic acid and sodium butyrate suppress the cardiac expression of hypertrophic markers and proinflammatory mediators in Npr1 gene-disrupted haplotype mice.

The objective of the present study was to examine the genetically determined differences in the natriuretic peptide receptor-A (NPRA) gene (Npr1) copies affecting the expression of cardiac hypertrophic markers, proinflammatory mediators, and matrix metalloproteinases (MMPs) in a gene-dose-dependent manner. We determined whether stimulation of Npr1 by all-trans retinoic acid (RA) and histone deacetylase (HDAC) inhibitor sodium butyric acid (SB) suppress the expression of cardiac disease markers. In the present study, we utilized Npr1 gene-disrupted heterozygous (Npr1(+/-), 1-copy), wild-type (Npr1(+/+), 2-copy), gene-duplicated (Npr1(++/+), 3-copy) mice, which were treated intraperitoneally with RA, SB, and a combination of RA/SB, a hybrid drug (HB) for 2 wk. Untreated 1-copy mice showed significantly increased heart weight-body weight (HW/BW) ratio, blood pressure, hypertrophic markers, including beta-myosin heavy chain (ß-MHC) and proto-oncogenes (c-fos and c-jun), proinflammatory mediator nuclear factor kappa B (NF-κB), and MMPs (MMP-2, MMP-9) compared with 2-copy and 3-copy mice. The heterozygous (haplotype) 1-copy mice treated with RA, SB, or HB, exhibited significant reduction in the expression of ß-MHC, c-fos, c-jun, NF-κB, MMP-2, and MMP-9. In drug-treated animals, the activity and expression levels of HDAC were significantly reduced and histone acetyltransferase activity and expression levels were increased. The drug treatments significantly increased the fractional shortening and reduced the systolic and diastolic parameters of the Npr1(+/-) mice hearts. Together, the present results demonstrate that a decreased Npr1 copy number enhanced the expression of hypertrophic markers, proinflammatory mediators, and MMPs, whereas an increased Npr1 repressed the cardiac disease markers in a gene-dose-dependent manner.

All-trans retinoic acid and sodium butyrate enhance natriuretic peptide receptor a gene transcription: role of histone modification.

The objective of the present study was to delineate the mechanisms of GC-A/natriuretic peptide receptor-A (GC-A/NPRA) gene (Npr1) expression in vivo. We used all-trans retinoic acid (ATRA) and histone deacetylase (HDAC) inhibitor, sodium butyrate (NaBu) to examine the expression and function of Npr1 using gene-disrupted heterozygous (1-copy; +/-), wild-type (2-copy; +/+), and gene-duplicated heterozygous (3-copy; ++/+) mice. Npr1(+/-) mice exhibited increased renal HDAC and reduced histone acetyltransferase (HAT) activity; on the contrary, Npr1(++/+) mice showed decreased HDAC and enhanced HAT activity compared with Npr1(+)(/+) mice. ATRA and NaBu promoted global acetylation of histones H3-K9/14 and H4-K12, reduced methylation of H3-K9 and H3-K27, and enriched accumulation of active chromatin marks at the Npr1 promoter. A combination of ATRA-NaBu promoted recruitment of activator-complex containing E26 transformation-specific 1, retinoic acid receptor α, and HATs (p300 and p300/cAMP response element-binding protein-binding protein-associated factor) at the Npr1 promoter, and significantly increased renal NPRA expression, GC activity, and cGMP levels. Untreated 1-copy mice showed significantly increased systolic blood pressure and renal expression of α-smooth muscle actin (α-SMA) and proliferating cell nuclear antigen (PCNA) compared with 2- and 3-copy mice. Treatment with ATRA and NaBu synergistically attenuated the expression of α-SMA and PCNA and reduced systolic blood pressure in Npr1(+/-) mice. Our findings demonstrate that epigenetic upregulation of Npr1 gene transcription by ATRA and NaBu leads to attenuation of renal fibrotic markers and systolic blood pressure in mice with reduced Npr1 gene copy number, which will have important implications in prevention and treatment of hypertension-related renal pathophysiological conditions.

Activation of IKK/NF-κB provokes renal inflammatory responses in guanylyl cyclase/natriuretic peptide receptor-A gene-knockout mice.

The present study was aimed at determining the consequences of the disruption of guanylyl cyclase/natriuretic peptide receptor-A (GC-A/NPRA) gene (Npr1) on proinflammatory responses of nuclear factor kappa B, inhibitory kappa B kinase, and inhibitory kappa B alpha (NF-κB, IKK, IκBα) in the kidneys of mutant mice. The results showed that the disruption of Npr1 enhanced the renal NF-κB binding activity by 3.8-fold in 0-copy (-/-) mice compared with 2-copy (+/+) mice. In parallel, IKK activity and IκBα protein phosphorylation were increased by 8- and 11-fold, respectively, in the kidneys of 0-copy mice compared with wild-type mice. Interestingly, IκBα was reduced by 80% and the expression of proinflammatory cytokines and renal fibrosis were significantly enhanced in 0-copy mice than 2-copy mice. Treatment of 0-copy mice with NF-κB inhibitors andrographolide, pyrrolidine dithiocarbamate, and etanercept showed a substantial reduction in renal fibrosis, attenuation of proinflammatory cytokines gene expression, and significantly reduced IKK activity and IkBα phosphorylation. These findings indicate that the systemic disruption of Npr1 activates the renal NF-κB pathways in 0-copy mice, which transactivates the expression of various proinflammatory cytokines to initiate renal remodeling; however, inhibition of NF-κB pathway repairs the abnormal renal pathology in mutant mice.