Takanori Matsuo

A new class of non-thiazolidinedione, non-carboxylic-acid-based highly selective peroxisome proliferator-activated receptor (PPAR) γ agonists: design and synthesis of benzylpyrazole acylsulfonamides.

Herein, we describe the design, synthesis, and structure-activity relationships of novel benzylpyrazole acylsulfonamides as non-thiazolidinedione (TZD), non-carboxylic-acid-based peroxisome proliferator-activated receptor (PPAR) γ agonists. Docking model analysis of in-house weak agonist 2 bound to the reported PPARγ ligand binding domain suggested that modification of the carboxylic acid of 2 would help strengthen the interaction of 2 with the TZD pocket and afford non-carboxylic-acid-based agonists. In this study, we used an acylsulfonamide group as the ring-opening analog of TZD as an isosteric replacement of carboxylic acid moiety of 2; further, preliminary modification of the terminal alkyl chain on the sulfonyl group gave the lead compound 3c. Subsequent optimization of the resulting compound gave the potent agonists 25c, 30b, and 30c with high metabolic stability and significant antidiabetic activity. Further, we have described the difference in binding mode of the carboxylic-acid-based agonist 1 and acylsulfonamide 3d.

Structure-activity relationships and key structural feature of pyridyloxybenzene-acylsulfonamides as new, potent, and selective peroxisome proliferator-activated receptor (PPAR) γ Agonists.

In our search for a novel class of non-TZD, non-carboxylic acid peroxisome proliferator-activated receptor (PPAR) γ agonists, we explored alternative lipophilic templates to replace benzylpyrazole core of the previously reported agonist 1. Introduction of a pentylsulfonamide group into arylpropionic acids derived from previous in-house PPARγ ligands succeeded in the identification of 2-pyridyloxybenzene-acylsulfonamide 2 as a lead compound. Docking studies of compound 2 suggested that a substituent para to the central benzene ring should be incorporated to effectively fill the Y-shaped cavity of the PPARγ ligand-binding domain (LBD). This strategy led to significant improvement of PPARγ activity. Further optimization to balance in vitro activity and metabolic stability allowed the discovery of the potent, selective and orally efficacious PPARγ agonist 8f. Structure-activity relationship study as well as detailed analysis of the binding mode of 8f to the PPARγ-LBD revealed the essential structural features of this series of ligands.

Blockade of renin-angiotensin system ameliorates renal injury in NIDDM model rats

AbstractBackground. Recently, inhibition of the renin-angiotensin system has been reported to be effective for patients with diabetic nephropathy. In this study, we examined the renal protective effects of candesartan cilexetil (TCV-116) in Wistar fatty rats, a model of non-insulin-dependent diabetes mellitus (NIDDM) with renal injuries. Methods. Twelve-week-old Wistar fatty rats received candesartan cilexetil (0.3 or 1 mg/kg) or enalapril (10 mg/kg) daily, administered orally, for 16 weeks. Routine laboratory parameters, such as urinary albumin and total protein excretion, were measured every 4 weeks, and renal function tests and histopathological studies were carried out at the end of the experiment. Results. In the 12-week-old Wistar fatty rats, plasma glucose and insulin levels were significantly higher than those in age-matched Wistar lean rats (normal controls). Urinary albumin and total protein excretion was slightly but significantly increased as compared to these parameters in Wistar lean rats, and increased further with time. Daily administration of candesartan cilexetil or enalapril inhibited the increase in urinary albumin and total protein excretion without affecting plasma glucose and insulin levels. In histopathological studies, candesartan cilexetil (0.3 and 1 mg/kg) and enalapril (10 mg/kg) prevented the glomerular injury observed in vehicle-treated rats. Candesartan cilexetil (1 mg/kg) and enalapril also inhibited tubular changes. Systolic blood pressure in the drug-treated groups was significantly decreased compared with that in vehicle-treated rats. Conclusions. Inhibitors of the renin-angiotensin system ameliorated proteinuria and the pathological changes of renal injuries in this NIDDM model. Candesartan cilexetil may be useful for the treatment of NIDDM patients with renal damage.

Phosphodiesterase 4 inhibitor and phosphodiesterase 5 inhibitor combination therapy has antifibrotic and anti-inflammatory effects in mdx mice with Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is the most common inherited muscular dystrophy. Patients experience DMD in their 20s from cardiac or respiratory failure related to progressive muscle wasting. Currently, the only treatments for the symptoms of DMD are available. Muscle fibrosis, a DMD feature, leads to reduced muscle function and muscle mass, and hampers pharmaceutical therapeutic efficacy. Although antifibrotic agents may be useful, none is currently approved. Phosphodiesterase 4 (PDE4) inhibitors have exhibited antifibrotic effects in human and animal models. In this study, we showed beneficial effects of the PDE4 inhibitor piclamilast in the DMD mdx mouse. Piclamilast reduced the mRNA level of profibrotic genes, including collagen 1A1, in the gastrocnemius and diaphragm, in the mdx mouse, and significantly reduced the Sirius red staining area. The PDE5 inhibitors sildenafil and tadalafil ameliorated functional muscle ischemia in boys with DMD, and sildenafil reversed cardiac dysfunction in the mdx mouse. Single‐treatment piclamilast or sildenafil showed similar antifibrotic effects on the gastrocnemius; combination therapy showed a potent antifibrotic effect, and piclamilast and combination therapy increased peroxisome proliferator‐activated receptor γ coactivator‐1α mRNA in mouse gastrocnemius. In summary, we confirmed that piclamilast has significant antifibrotic effects in mdx mouse muscle and is a potential treatment for muscle fibrosis in DMD.—Nio, Y., Tanaka, M., Hirozane, Y., Muraki, Y., Okawara, M., Hazama, M., Matsuo, T. Phosphodiesterase 4 inhibitor and phosphodiesterase 5 inhibitor combination therapy has antifibrotic and anti‐inflammatory effects in mdx mice with Duchenne muscular dystrophy. FASEB J. 31, 5307–5320 (2017). www.fasebj.org

Phosphodiesterase 4 inhibition reduces lung fibrosis following targeted type II alveolar epithelial cell injury

Fibrosis of the lung constitutes a major clinical challenge and novel therapies are required to alleviate the associated morbidity and mortality. Investigating the antifibrotic efficacy of drugs that are already in clinical practice offers an efficient strategy to identify new therapies. The phosphodiesterase 4 (PDE4) inhibitors, approved for the treatment of chronic obstructive pulmonary disease, harbor therapeutic potential for pulmonary fibrosis by augmenting the activity of endogenous antifibrotic mediators that signal through cyclic AMP. In this study, we tested the efficacy of several PDE4 inhibitors including a novel compound (Compound 1) in a murine model of lung fibrosis that results from a targeted type II alveolar epithelial cell injury. We also compared the antifibrotic activity of PDE4 inhibition to the two therapies that are FDA‐approved for idiopathic pulmonary fibrosis (pirfenidone and nintedanib). We found that both preventative (day 0–21) and therapeutic (day 11–21) dosing regimens of the PDE4 inhibitors significantly ameliorated the weight loss and lung collagen accumulation that are the sequelae of targeted epithelial cell damage. In a therapeutic protocol, the reduction in lung fibrosis with PDE4 inhibitor administration was equivalent to pirfenidone and nintedanib. Treatment with this class of drugs also resulted in a decrease in plasma surfactant protein D concentration, a reduction in the plasma levels of several chemokines implicated in lung fibrosis, and an in vitro inhibition of fibroblast profibrotic gene expression. These results motivate further investigation of PDE4 inhibition as a treatment for patients with fibrotic lung disease.

Fluorescent Imaging Analysis for Distribution of Fluorescent Dye Labeled- or Encapsulated-Liposome in Monocrotaline-Induced Pulmonary Hypertension Model Rat

Pulmonary hypertension (PH) is a life-threatening lung disease. Despite the availability of several approved drugs, the development of a new treatment method is needed because of poor prognosis. Tissue selective drug delivery systems can avoid the adverse effects of current therapy and enhance efficacy. We evaluated the possibility of delivering drugs to the lungs of a PH rat model using fluorescence dye-labeled nanosized liposomes. To evaluate the tissue distribution following systemic exposure, fluorescent dye-labeled, 40-180 nm liposomes with and without polyethylene glycol (PEG) were intravenously administered to a monocrotaline-induced PH (MCT) rat model and tissue fluorescence was measured. Fluorescent dye-containing liposomes were intratracheally administered to the MCT model to evaluate the distribution of the liposome-encapsulated compound following local administration to reduce systemic exposure. The lung vascular permeability, plasma concentration of surfactant protein (SP)-D, lung reactive oxygen species (ROS) production, and macrophage marker gene cluster of differentiation (CD68) expression were measured. PEG and 80-nm liposome accumulation in the lung was elevated in the MCT model compared to that in normal rats. The intratracheally administered liposomes were delivered selectively to the lungs of the MCT model. The lung vascular permeability, plasma SP-D concentration, and CD68 expression were significantly elevated in the lungs of the MCT model, and were all significantly and positively correlated to liposome lung accumulation. Liposomes can accumulate in the lungs of an MCT model by enhancing vascular permeability by the inflammatory response. Therefore, drug encapsulation in liposomes could be an effective method of drug delivery in patients with PH.

Podocan Is Expressed in Blood and Adipose Tissue and Correlates Negatively With the Induction of Diabetic Nephropathy

Podocan, a member of the small leucine-rich repeat proteoglycans (SLRPs), is expressed in vascular endothelial cells with high levels of expression in the sclerotic glomerular lesions of experimental HIV-associated nephropathy. It is also found in vascular smooth muscle cells and is involved in atherosclerosis. Decorin, a protein similar to podocan, also belongs to the SLRP family and is highly expressed in adipose tissues. It is a secreted protein associated with obesity, type 2 diabetes, and diabetic nephropathy. Based on the similarity of podocan to decorin and its functions reported in the renal and cardiovascular systems, we hypothesized that podocan levels might correlate with the occurrence of metabolic syndromes such as obesity, diabetes, and diabetic nephropathy. We found that podocan was highly expressed in the adipose tissue of mice and humans and its expression was regulated by tumor necrosis factor-α in mouse 3T3-L1 adipocytes. In addition, podocan was detected in the plasma, and its levels tended to increase in diet-induced obese C57BL/6J mice and decrease in obese-diabetic KKAy and db/db mice. Podocan messenger RNA (mRNA) levels in the renal cortex correlated negatively with the urinary albumin-to-creatinine ratio, a surrogate marker of glomerular injury in uninephrectomized db/db mice used as a model of diabetic nephropathy. Our results suggest that podocan is involved in kidney function and could be a unique therapeutic target for diabetic nephropathy.