Direct Blood Pressure-Independent Anti-Fibrotic Effects by the Selective Nonsteroidal Mineralocorticoid Receptor Antagonist Finerenone in Progressive Models of Kidney Fibrosis.

INTRODUCTION: The nonsteroidal mineralocorticoid receptor (MR) antagonist finerenone and sodium-glucose cotransporter-2 (SGLT2) inhibitors have demonstrated clinical benefits in chronic kidney disease patients with type 2 diabetes. Precise molecular mechanisms responsible for these benefits are incompletely understood. Here, we investigated potential direct anti-fibrotic effects and mechanisms of nonsteroidal MR antagonism by finerenone or SGLT2 inhibition by empagliflozin in 2 relevant mouse kidney fibrosis models: unilateral ureter obstruction and sub-chronic ischemia reperfusion injury. METHODS: Kidney fibrosis was induced in mice via unilateral ureteral obstruction or ischemia. In a series of experiments, mice were treated orally with the MR antagonist finerenone (3 or 10 mg/kg), the SGLT2 inhibitor empagliflozin (10 or 30 mg/kg), or in a direct comparison of both drugs. Interstitial myofibroblast accumulation was quantified via alpha-smooth muscle actin and interstitial collagen deposition via Sirius Red/Fast Green staining in both models. Secondary analyses included the assessment of inflammatory cells, kidney mRNA expression of fibrotic markers as well as functional parameters (serum creatinine and albuminuria) in the ischemic model. Blood pressure was measured via telemetry in healthy conscious compound-treated animals. RESULTS: Finerenone dose-dependently decreased pathological myofibroblast accumulation and collagen deposition with no effects on systemic blood pressure and inflammatory markers in the tested dose range. Reduced kidney fibrosis was paralleled by reduced kidney plasminogen activator inhibitor-1 (PAI-1) and naked cuticle 2 (NKD2) expression in finerenone-treated mice. In contrast, treatment with empagliflozin strongly increased urinary glucose excretion in both models and reduced ischemia-induced albuminuria but had no effects on kidney myofibroblasts or collagen deposition. DISCUSSION/CONCLUSION: Finerenone has direct anti-fibrotic properties resulting in reduced myofibroblast and collagen deposition accompanied by a reduction in renal PAI-1 and NKD2 expression in mouse models of progressive kidney fibrosis at blood pressure-independent dosages.

Riociguat for the treatment of Phe508del homozygous adults with cystic fibrosis.

BACKGROUND: Riociguat is a first-in-class soluble guanylate cyclase stimulator for which preclinical data suggested improvements in cystic fibrosis transmembrane conductance regulator (CFTR) function. METHODS: This international, multicenter, two-part, Phase II study of riociguat enrolled adults with cystic fibrosis (CF) homozygous for Phe508del CFTR. Part 1 was a 28-day, randomized, double-blind, placebo-controlled study in participants not receiving CFTR modulator therapy. Twenty-one participants were randomized 1:2 to placebo or oral riociguat (0.5 mg three times daily [tid] for 14 days, increased to 1.0 mg tid for the subsequent 14 days). The primary and secondary efficacy endpoints were change in sweat chloride concentration and percent predicted forced expiratory volume in 1 second (ppFEV1), respectively, from baseline to Day 14 and Day 28 with riociguat compared with placebo. RESULTS: Riociguat did not alter CFTR activity (change in sweat chloride) or lung function (change in ppFEV1) at doses up to 1.0 mg tid after 28 days. The most common drug-related adverse event (AE) was headache occurring in three participants (21%); serious AEs occurred in one participant receiving riociguat (7%) and one participant receiving placebo (14%). This safety profile was consistent with the underlying disease and the known safety of riociguat for its approved indications. CONCLUSIONS: The Rio-CF study was terminated due to lack of efficacy and the changing landscape of CF therapeutic development. The current study⁠, within its limits of a small sample size, did not provide evidence that riociguat could be a valid treatment option for CF. CLINICAL TRIAL REGISTRATION NUMBER: NCT02170025.

Effects of Finerenone Combined with Empagliflozin in a Model of Hypertension-Induced End-Organ Damage.

INTRODUCTION: The nonsteroidal mineralocorticoid receptor (MR) antagonist finerenone and sodium-glucose cotransporter-2 (SGLT2) inhibitors have demonstrated clinical benefits in CKD patients with type 2 diabetes. Clinical data analyzing the potential value of a combination therapy are currently limited. We therefore investigated cardiorenal protection of respective mono- and combination therapy in a preclinical model of hypertension-induced end-organ damage. METHODS: Cardiovascular (CV) morbidity and mortality were studied in hypertensive, N(ω)-nitro-L-arginine methyl ester-treated, renin-transgenic (mRen2)27 rats. Rats (10- to 11-week-old females, n = 13-17/group) were treated once daily orally for up to 7 weeks with placebo, finerenone (1 and 3 mg/kg), empagliflozin (3 and 10 mg/kg), or a combination of the respective low doses. Key outcome parameters included mortality, proteinuria, plasma creatinine and uric acid, blood pressure, and cardiac and renal histology. RESULTS: Placebo-treated rats demonstrated a 50% survival rate over the course of 7 weeks. Drug treatment resulted in variable degrees of survival benefit, most prominently in the low-dose combination group with a survival benefit of 93%. Monotherapies of finerenone or empagliflozin dose-dependently reduced proteinuria, while low-dose combination revealed an early, sustained, and over-additive reduction in proteinuria. Empagliflozin induced a strong and dose-dependent increase in urinary glucose excretion which was not influenced by finerenone coadministration in the combination arm. Low-dose combination but not respective low-dose monotherapies significantly reduced plasma creatinine and plasma uric acid after 6 weeks. Treatment with finerenone and the low-dose combination significantly decreased systolic blood pressure after 5 weeks. There was a dose-dependent protection from cardiac and kidney fibrosis and vasculopathy with both agents, while low-dose combination therapy was more efficient than the respective monotherapy dosages on most cardiorenal histology parameters. DISCUSSION/CONCLUSIONS: Nonsteroidal MR antagonism by finerenone and SGLT2 inhibition by empagliflozin confer CV protection in preclinical hypertension-induced cardiorenal disease. Combination of these 2 independent modes of action at low dosages revealed efficacious reduction in important functional parameters such as proteinuria and blood pressure, plasma markers including creatinine and uric acid, cardiac and renal lesions as determined by histopathology, and mortality indicating a strong potential for combined clinical use in cardiorenal patient populations.

Pharmacodynamics, Pharmacokinetics, and Antiviral Activity of BAY 81-8781, a Novel NF-κB Inhibiting Anti-influenza Drug.

Influenza is a respiratory disease that causes annual epidemics. Antiviral treatment options targeting the virus exist, but their efficiency is limited and influenza virus strains easily develop resistance. Thus, new treatment strategies are urgently needed. In the present study, we investigated the anti-influenza virus properties of D,L-lysine acetylsalicylate ⋅ glycine (BAY 81-8781; LASAG) that is approved as Aspirin i.v. for intravenous application. Instead of targeting the virus directly BAY 81-8781 inhibits the activation of the NF-κB pathway, which is required for efficient influenza virus propagation. Using highly pathogenic avian influenza virus strains we could demonstrate that BAY 81-8781 was able to control influenza virus infection in vitro. In the mouse infection model, inhalation of BAY 81-8781 resulted in reduced lung virus titers and protection of mice from lethal infection. Pharmacological studies demonstrated that the oral route of administration was not suitable to reach the sufficient concentrations of BAY 81-8781 for a successful antiviral effect in the lung. BAY 81-8781 treatment of mice infected with influenza virus started as late as 48 h after infection was still effective in protecting 50% of the animals from death. In summary, the data represent a successful proof of the novel innovative antiviral concept of targeting a host cell signaling pathway that is required for viral propagation instead of viral structures.

The NF-kappaB inhibitor SC75741 protects mice against highly pathogenic avian influenza A virus.

The appearance of pandemic H1N1 and highly pathogenic avian H5N1 viruses in humans as well as the emergence of seasonal H1N1 variants resistant against neuraminidase inhibitors highlight the urgent need for new and amply available antiviral drugs. We and others have demonstrated that influenza virus misuses the cellular IKK/NF-kappaB signaling pathway for efficient replication suggesting that this module may be a suitable target for antiviral intervention. Here, we show that the novel NF-kappaB inhibitor SC75741 significantly protects mice against infection with highly pathogenic avian influenza A viruses of the H5N1 and H7N7 subtypes. Treatment was efficient when SC75741 was given intravenously in a concentration of 5mg/kg/day. In addition, application of SC75741 via the intraperitoneal route resulted in a high bioavailability and was also efficient against influenza when given 15 mg/kg/day or 7.5 mg/kg/twice a day. Protection was achieved when SC75741 was given for seven consecutive days either prior to infection or as late as four days after infection. SC75741 treatment showed no adverse effects in the concentrations required to protect mice against influenza virus infection. Although more pre-clinical studies are needed SC75741 might be a promising candidate for a novel antiviral drug against influenza viruses that targets the host cell rather than the virus itself.

Modification of the salivary secretion assay in F508del mice--the murine equivalent of the human sweat test.

BACKGROUND: In 2005 Best and Quinton established the salivary secretion assay in mice for the in vivo characterization of new drugs against cystic fibrosis (CF). However, limited data are available and the predictive value of this in vivo assay for treatment effects in CF patients is not fully understood. METHODS: Therefore, we revisited the salivary secretion assay and systematically investigated the salivary secretion rates in different murine backgrounds and sexes, as well as in different CF mouse models. Moreover, we established quantification of salivary chloride content. RESULTS: We found a strain- and sex-dependency of salivary secretion rates and were able to confirm the decreased ß-adrenergic salivary secretion response in CFTR knockout mice (CFTR(tm1Unc)) as well as in the F508del CFTR mice of different origins (CFTR(tm1Kth) and CFTR(tm1Eur)). In heterozygous Cftr+/- and Cftr+/F508del mice, the isoprenaline-stimulated salivary secretion rate and the Cl(-) content were intermediate between values measured in WT and CF mice, indicating that this assay is also able to detect CF carriership. Pilocarpine-induced abnormalities in saliva chloride content in CF mice resembled the changes observed in the human sweat test. CONCLUSIONS: Determination of murine salivary chloride content in combination with salivary secretion rate in CF mice may render the salivary secretion assay as a powerful tool for validation of new CF treatments.

Antiviral activity of the MEK-inhibitor U0126 against pandemic H1N1v and highly pathogenic avian influenza virus in vitro and in vivo.

The emergence of the 2009 H1N1 pandemic swine influenza A virus is a good example of how this viral infection can impact health systems around the world in a very short time. The continuous zoonotic circulation and reassortment potential of influenza A viruses (IAV) in nature represents an enormous public health threat to humans. Beside vaccination antivirals are needed to efficiently control spreading of the disease. In the present work we investigated whether the MEK inhibitor U0126, targeting the intracellular Raf/MEK/ERK signaling pathway, is able to suppress propagation of the 2009 pandemic IV H1N1v (v=variant) as well as highly pathogenic avian influenza viruses (HPAIV) in cell culture and also in vivo in the mouse lung. U0126 showed antiviral activity in cell culture against all tested IAV strains including oseltamivir resistant variants. Furthermore, we were able to demonstrate that treatment of mice with U0126 via the aerosol route led to (i) inhibition of MEK activation in the lung (ii) reduction of progeny IAV titers compared to untreated controls (iii) protection of IAV infected mice against a 100× lethal viral challenge. Moreover, no adverse effects of U0126 were found in cell culture or in the mouse. Thus, we conclude that U0126, by inhibiting the cellular target MEK, has an antiviral potential not only in vitro in cell culture, but also in vivo in the mouse model.

Low-dose interferon Type I treatment is effective against H5N1 and swine-origin H1N1 influenza A viruses in vitro and in vivo.

The recent emergence of pandemic swine-origin influenza virus (H1N1) and the severe outbreaks of highly pathogenic avian influenza virus of the H5N1 subtype leading to death in humans is a reminder that influenza remains a frightening foe throughout the world. Besides vaccination, there is an urgent need for new antiviral strategies to protect against influenza. The innate immune response to influenza viruses involves production of interferon alpha and beta (IFN-α/ß), which plays a crucial role in virus clearance during the initial stage of infection. We examined the effect of IFN-α on the replication of H5N1 and H1N1 in vitro and in vivo. A single pretreatment with low-dose IFN-α reduced lung virus titers up to 1.4 log(10) pfu. The antiviral effect increased after multiple pretreatments. Low-dose IFN-α protected mice against lethal H5N1 viral infection. Further, IFN-α was also effective against H1N1 in vitro and in the mouse model. These results indicate that low-dose IFN-α treatment leads to the induction of antiviral cytokines that are involved in the reduction of influenza virus titers in the lung. Moreover, it might be possible that a medical application during pandemic outbreak could help contain fulminant infections.

Influenza virus H5N1 hemagglutinin (HA) T-cell epitope conjugates: design, synthesis and immunogenicity.

The influenza virus, major surface glycoprotein hemagglutinin (HA) is one of the principal targets for the development of protective immunity. Aiming at contributing to the development of a vaccine that remains the first choice for prophylactic intervention, a reconstituted model of HA, mimicking its antigenic properties was designed, synthesized and tested in mice for the induction of protective immunity. Four helper T lymphocyte [HTL (T(1) , T(3) , T(7) and T(8) )] and four cytotoxic lymphocyte [CTL (T(2) , T(4) , T(5) and T(6) )] epitopes were coupled in two copies each to an artificial carrier, SOC(4) , which was formed by the repeating tripeptide Lys-Aib-Gly. The helical conformation of the SOC(4) -conjugates preserves the initial topology of the attached epitopes, which is critical for their immunogenic properties. Survival of immunized animals, ranged from 30 to 50%, points out the induction of protective immunity by using the SOC(4) -conjugates.

Highly pathogenic influenza virus infection of the thymus interferes with T lymphocyte development.

Highly pathogenic avian influenza viruses (HPAIVs) cause severe disease in humans. Still, the basis for their increased pathogenesis remains unclear. Additionally, the high morbidity in the younger population stays inexplicable, and the recent pandemic H1N1v outbreak in 2009 demonstrated the urgent need for a better understanding about influenza virus infection. In the present study, we demonstrated that HPAIV infection of mice not only led to lung destruction but also to functional damage of the thymus. Moreover, respiratory dendritic cells in the lung functioned as targets for HPAIV infection being able to transport infectious virus from the lung into the thymus. The pandemic H1N1 influenza virus was able to infect respiratory dendritic cells without a proper transport to the thymus. The strong interference of HPAIV with the immune system is especially devastating for the host and can lead to lymphopenia. In summary, from our data, we conclude that highly pathogenic influenza viruses are able to reach the thymus via dendritic cells and to interfere with T lymphocyte development. Moreover, this exceptional mechanism might not only be found in influenza virus infection, but also might be the reason for the increased immune evasion of some new emerging pathogens.

The alternative NF-kappaB signalling pathway is a prerequisite for an appropriate immune response against lymphocytic choriomeningitis virus infection.

Two major nuclear factor-kappaB (NF-kappaB) signalling pathways are involved in the regulation of the immune response. While the classical NF-kappaB pathway is responsible for regulation of genes encoding components of the innate immune response, the alternative NF-kappaB signalling pathway mediates processes of the adaptive immune system. To evaluate the role of the NF-kappaB signalling pathways in the control of viral infection, we have used lymphocytic choriomeningitis virus (LCMV) infection of mice, which is known to be an excellent model for studying antiviral immune responses. Via the use of mice that were deficient in NF-kappaB subunits from either the classical (p50(-/-) mice) or the alternative NF-kappaB pathway (p52(-/-) mice), we were able to demonstrate that the alternative NF-kappaB pathway is required for the T-cell-mediated immune response against LCMV. Mice that were deficient in the alternative NF-kappaB pathway subunit p52 showed an impaired T-cell response against LCMV infection. Furthermore, these mice also showed an impaired T-cell-dependent humoral immune response against vesicular stomatitis virus (VSV) infection. Adoptive transfer experiments revealed that impaired priming, but not the T-cell response itself, was responsible for the defective cellular immune response against LCMV infection. Our data demonstrate that a functional alternative NF-kappaB signalling pathway is required to assure an adequate immune response after viral infection.

Antibodies and CD4(+) T-cells mediate cross-protection against H5N1 influenza virus infection in mice after vaccination with a low pathogenic H5N2 strain.

A H5N2 low pathogenic avian influenza virus (LPAIV) was isolated from a natural reservoir in Bavaria during a routine screen and was used as a vaccine strain to scrutinize the immune response involved in cross-protection after challenge infection with a H5N1 highly pathogenic avian influenza virus (HPAIV). The challenge virus was also isolated from a natural reservoir in Bavaria. Wild type, antibody deficient (muMT), CD4(-/-) and CD8(-/-) mice were infected with the apathogenic H5N2 vaccine strain and challenge infection with a 100-fold MLD(50) of the H5N1 strain was performed 80 days later. While 100% of the wild type and 100% of the CD8(-/-) mice stayed healthy, only 50% of the CD4(-/-) and none of the antibody deficient mice were protected. These results support the view that the humoral immune response and to certain extends the CD4(+) T helper cells are a prerequisite for cross-protective immunity against H5 influenza virus.

Role of hypercytokinemia in NF-kappaB p50-deficient mice after H5N1 influenza A virus infection.

During H5N1 influenza virus infection, proinflammatory cytokines are markedly elevated in the lungs of infected hosts. The significance of this dysregulated cytokine response in H5N1-mediated pathogenesis remains to be determined. To investigate the influence of hypercytokinemia, or "cytokine storm," a transgenic mouse technology was used. The classical NF-kappaB pathway regulates the induction of most proinflammatory cytokines. Deletion of the p50 subunit leads to a markedly reduced expression of the NF-kappaB-regulated cytokines and chemokines. Here we show that H5N1 influenza virus infection of this transgenic mouse model resulted in a lack of hypercytokinemia but not in altered pathogenesis.

A polyphenol rich plant extract, CYSTUS052, exerts anti influenza virus activity in cell culture without toxic side effects or the tendency to induce viral resistance.

Infections with influenza A viruses still pose a major threat to humans and several animal species. The occurrence of highly pathogenic avian influenza viruses of the H5N1 subtype capable to infect and kill humans highlights the urgent need for new and efficient countermeasures against this viral disease. Here we demonstrate that a polyphenol rich extract (CYSTUS052) from the Mediterranean plant Cistus incanus exerts a potent anti-influenza virus activity in A549 or MDCK cell cultures infected with prototype avian and human influenza strains of different subtypes. CYSTUS052 treatment resulted in a reduction of progeny virus titers of up to two logs. At the effective dose of 50 microg/ml the extract did not exhibit apparent harming effects on cell viability, metabolism or proliferation, which is consistent with the fact that these plant extracts are already used in traditional medicine in southern Europe for centuries without any reported complications. Viruses did not develop resistance to CYSTUS052 when compared to amantadine that resulted in the generation of resistant variants after only a few passages. On a molecular basis the protective effect of CYSTUS052 appears to be mainly due to binding of the polymeric polyphenol components of the extract to the virus surface, thereby inhibiting binding of the hemagglutinin to cellular receptors. Thus, a local application of CYSTUS052 at the viral entry routes may be a promising approach that may help to protect from influenza virus infections.

CYSTUS052, a polyphenol-rich plant extract, exerts anti-influenza virus activity in mice.

Influenza, a respiratory disease caused by influenza viruses, is still a worldwide threat with a high potential to cause a pandemic. Beside vaccination, only two classes of drugs are available for antiviral treatment against the pathogen. Here we show that CYSTUS052, a plant extract from a special variety of Cistus incanus that is rich in polymeric polyphenols, exhibits antiviral activity against a highly pathogenic avian influenza A virus (H7N7) in cell culture and in a mouse infection model. In vitro and in vivo treatment was performed with an aerosol formulation, because the bioavailability of high molecular weight polyphenols is poor. In MDCK cells, a 90% reduction of plaque numbers on cells pre-incubated with the plant extract was achieved. For in vivo experiments we used a novel monitoring system for influenza A virus-infected mice that allows measurement of body temperature and gross motor-activity of the animals. Mice treated with CYSTUS052 did not develop disease, showed neither differences in their body temperature nor differences in their gross motor-activity and exhibited no histological alterations of the bronchiolus epithelial cells.