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Renal inflammation is a final common pathway of chronic kidney disease (CKD), and its progression can be used to effectively gauge the degree of renal dysfunction. Inflammatory mechanisms contribute to glomerulosclerosis and tubulointerstitial fibrosis, which are hallmarks of CKD leading to end-stage renal disease. Receptor-interacting protein kinase 2 (RIP2) is largely committed to nucleotide-binding oligomerization domain signaling as a direct effector and transmits nuclear factor-κB (NF-κB)-mediated proinflammatory cytokine production. In the present study, we hypothesized that if inflammation via RIP2 and NF-κB signaling plays an important role in renal failure, then the anti-inflammatory effect of RIP2 inhibitors should be effective in improving CKD. To determine its pharmacologic potency, we investigated the renoprotective properties of the novel RIP2 inhibitor AS3334034 [7-methoxy-6-(2-methylpropane-2-sulfonyl)-N-(4-methyl-1H-pyrazol-3-yl)quinolin-4-amine] in uninephrectomized adriamycin-induced CKD rats. Six weeks' repeated administration of AS3334034 (10 mg/kg, once daily) significantly reduced urinary protein excretion and prevented the development of glomerulosclerosis and tubulointerstitial fibrosis. In addition, AS3334034 showed beneficial effects on renal function, as demonstrated by a decrease in levels of plasma creatinine and blood urea nitrogen and attenuation of a decline in creatinine clearance. Furthermore, AS3334034 significantly attenuated inflammation, renal apoptosis, and glomerular podocyte loss. These results suggest that the RIP2 inhibitor AS3334034 suppresses the progression of chronic renal failure via an anti-inflammatory effect and is therefore potentially useful in treating patients with CKD. SIGNIFICANCE STATEMENT: The receptor-interacting protein kinase 2 (RIP2) inhibitor AS3334034 suppresses the progression of chronic renal failure via an anti-inflammatory effect, suggesting that the nucleotide-binding oligomerization domain-RIP2 axis might play a crucial role in the pathogenesis of inflammatory kidney diseases. AS3334034 is expected to be potentially useful in the treatment of patients with chronic kidney disease.

Vascular adhesion protein-1 (VAP-1) is a promising therapeutic target for the treatment of diabetic nephropathy. Here, we conducted structural optimization of the glycine amide derivative 1, which we previously reported as a novel VAP-1 inhibitor, to improve stability in dog and monkey plasma, and aqueous solubility. By chemical modification of the right part in the glycine amide derivative, we identified the carbamimidoylcarbamate derivative 20c, which showed stability in dog and monkey plasma while maintaining VAP-1 inhibitory activity. We also found that conversion of the pyrimidine ring in 20c into saturated rings was effective for improving aqueous solubility. This led to the identification of 28a and 35 as moderate VAP-1 inhibitors with excellent aqueous solubility. Further optimization led to the identification of 2-fluoro-3-{3-[(6-methylpyridin-3-yl)oxy]azetidin-1-yl}benzyl carbamimidoylcarbamate (40b), which showed similar human VAP-1 inhibitory activity to 1 with improved aqueous solubility. 40b showed more potent ex vivo efficacy than 1, with rat plasma VAP-1 inhibitory activity of 92% at 1h after oral administration at 0.3mg/kg. In our pharmacokinetic study, 40b showed good oral bioavailability in rats, dogs, and monkeys, which may be due to its improved stability in dog and monkey plasma.

Vascular adhesion protein-1 (VAP-1) is a promising therapeutic target for the treatment of diabetic nephropathy. Here, we conducted optimization studies of our lead compound 1 , which we previously reported as a novel VAP-1 inhibitor, to enhance the inhibition of human VAP-1 and to reduce CYP3A4 and CYP2C19 inhibition. As a result, we identified 3-chloro-4-{4-[5-(3-{[glycyl(methyl)amino]methyl}phenyl)pyrimidin-2-yl]piperazin-1-yl}benzoic acid ( 17h ) as a novel orally active VAP-1 inhibitor, with 14-fold increased human VAP-1 inhibitory activity compared to 1 , without CYP3A4 and CYP2C19 inhibition. Oral administration of 17h significantly inhibited the progression of proteinuria in streptozotocin (STZ) induced diabetic rats at 0.3 and 1 mg/kg, suggesting that this compound has potential to be a therapeutic agent for the treatment of diabetic nephropathy.

Renal inflammation is a final common pathway of chronic kidney disease including diabetic nephropathy, which is the leading cause of end-stage renal disease and is associated with high cardiovascular risk and significant morbidity and mortality. Interleukin-1 (IL-1) receptor-associated kinase 4 (IRAK-4) is a pivotal molecule for IL-1 receptor- and Toll-like receptor-induced activation of proinflammatory mediators. In this study, we investigated the renoprotective properties of IRAK-4 inhibitor AS2444697 in KK/Ay type 2 diabetic mice. Four-week repeated administration of AS2444697 dose-dependently and significantly improved albuminuria; hyperfiltration, as measured by creatinine clearance; renal injury, including glomerulosclerosis; tubular injury markers, including urinary N-acetyl-β-D-glucosaminidase activity; and glomerular podocyte injury markers, including urinary nephrin excretion. In addition, AS2444697 attenuated plasma levels of proinflammatory cytokines, including IL-6; plasma levels of endothelial dysfunction markers, including intercellular adhesion molecule-1; and plasma levels and renal contents of oxidative stress markers. In contrast, AS2444697 did not significantly affect food intake or blood glucose levels. These results suggest that AS2444697 attenuates the progression of diabetic nephropathy mainly via anti-inflammatory mechanisms through inhibition of IRAK-4 activity under diabetic conditions and may represent a promising therapeutic option for the treatment of type 2 diabetic nephropathy.

Urinary nephrin is a potential non-invasive biomarker of disease. To date, however, most studies of urinary nephrin have been conducted in animal models of diabetic nephropathy, and correlations between urinary nephrin-to-creatinine ratio and other parameters have yet to be evaluated in animal models or patients of kidney disease with podocyte dysfunction. We hypothesized that urinary nephrin-to-creatinine ratio can be up-regulated and is negatively correlated with renal nephrin mRNA levels in animal models of kidney disease, and that increased urinary nephrin-to-creatinine ratio levels are attenuated following administration of glucocorticoids. In the present study, renal nephrin mRNA, urinary nephrin-to-creatinine ratio, urinary protein-to-creatinine ratio, and creatinine clearance ratio were measured in animal models of adriamycin nephropathy, puromycin aminonucleoside nephropathy, anti-glomerular basement membrane glomerulonephritis, and 5/6 nephrectomy. The effects of prednisolone on urinary nephrin-to-creatinine ratio and other parameters in puromycin aminonucleoside (single injection) nephropathy rats were also investigated. In all models tested, urinary nephrin-to-creatinine ratio and urinary protein-to-creatinine ratio increased, while renal nephrin mRNA and creatinine clearance ratio decreased. Urinary nephrin-to-creatinine ratio exhibited a significant negative correlation with renal nephrin mRNA in almost all models, as well as a significant positive correlation with urinary protein-to-creatinine ratio and a significant negative correlation with creatinine clearance ratio. Urinary protein-to-creatinine ratio exhibited a significant negative correlation with renal nephrin mRNA. Following the administration of prednisolone to puromycin aminonucleoside (single injection) nephropathy rats, urinary nephrin-to-creatinine ratio was significantly suppressed and exhibited a significant positive correlation with urinary protein-to-creatinine ratio. In addition, the decrease in number of glomerular Wilms tumor antigen-1-positive cells was attenuated, and urinary nephrin-to-creatinine ratio exhibited a significant negative correlation in these cells. In conclusion, these results suggest that urinary nephrin-to-creatinine ratio level is a useful and reliable biomarker for predicting the amelioration of podocyte dysfunction by candidate drugs in various kidney disease models with podocyte dysfunction. This suggestion will also be validated in a clinical setting in future studies.

We implemented a Mathematica module of CGA which includes functions to denote CGA elements and compute several operations in CGA. We can draw the figure in 3D space which is corresponding to a CGA element. Our draw function is using Gr\"{o}bner Basis for simplifying equations of figures. It can be used for any dimensional figures. One of our motivations is to realize 3D origami system using our own CGA Library. We follow the 2D computational origami system E-Origami-System developed by Ida et.al. and formulated simple fold operations in 3D by using CGA points and motions. Then, we proved some geometric theorems about origami properties by computing CGA equation formulas.

Vascular Adhesion Protein-1 (VAP-1) is a promising therapeutic target for the treatment of several inflammatory-related diseases including diabetic microvascular complication. We identified glycine amide derivative 3 as a novel structure with moderate VAP-1 inhibitory activity. Structure-activity relationship studies of glycine amide derivatives revealed that the tertiary amide moiety is important for stability in rat blood and that the position of substituents on the left phenyl ring plays an important role in VAP-1 inhibitory activity. We also found that low TPSA values and weak basicity are both important for high PAMPA values for glycine amide derivatives. These findings led to the identification of a series of orally active compounds with enhanced VAP-1 inhibitory activity. Of these compounds, 4g exhibited the most potent ex vivo efficacy, with plasma VAP-1 inhibitory activity of 60% after oral administration at 1mg/kg.

The species selectivity of four structurally different compounds, SCH-351125, E-913, TAK-779 and UK-427857 has been examined using cloned human, rhesus, and mouse CCR5 receptors. SCH-351125 and E-913 potently inhibited the binding of [125I]-CCL3 to human CCR5, but their inhibitory activities against rhesus CCR5 were more than 10-fold weaker. In contrast, TAK-779 and UK-427857 inhibited binding to human and rhesus CCR5 with similar potency. The inhibitory activities of all four compounds against mice CCR5 receptors were weak. The inhibitory activities of the CCR5 antagonists in the [125I]-CCL3 binding assay agreed well with those induced by CCL3 in the intracellular calcium ([Ca(2+)]i) elevation assay. Mutational analysis of the human CCR5 receptor showed that its Ile198 component plays a critical role in the inhibitory activities of both SCH-351125 and E-913, but not that of TAK-779 or UK-427857. These results provide a structural basis for understanding how specific antagonists interact with CCR5, and will aid the process of creating new, improved CCR5 antagonists.

Prostaglandin D(2) (PGD(2)), a major cyclooxygenase product in a variety of tissues and cells, readily undergoes dehydration to yield electrophilic PGs, such as 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)). We have previously shown that 15d-PGJ(2) potently induces apoptosis of SH-SY5Y human neuroblastoma cells via accumulation of the tumor suppressor gene product p53. In the study presented here, we investigated the molecular mechanisms involved in the 15d-PGJ(2)-induced accumulation of p53. It was observed that 15d-PGJ(2) potently induced p53 protein expression but scarcely induced p53 gene expression. In addition, exposure of the cells to 15d-PGJ(2) resulted in an accumulation of ubiquitinated proteins and in a significant inhibition of proteasome activities, suggesting that 15d-PGJ(2) acted on the ubiquitin-proteasome pathway, a regulatory mechanism of p53 turnover. The effects of 15d-PGJ(2) on the protein turnover were attributed to its electrophilic feature, based on the observations that (i) the reduction of the double bond in the cyclopentenone ring of 15d-PGJ(2) virtually abolished the effects on protein turnover, (ii) overexpression of an endogenous redox regulator, thioredoxin 1, significantly retarded the inhibition of proteasome activities and accumulations of p53 and ubiquitinated proteins induced by 15d-PGJ(2), and (iii) treatment of SH-SY5Y cells with biotinylated 15d-PGJ(2) indeed resulted in the formation of a 15d-PGJ(2)-proteasome conjugate. These data suggest that the modulation of proteasome activity may be involved in the mechanism responsible for the accumulation of p53 and subsequent induction of apoptotic cell death induced by 15d-PGJ(2).

Prostaglandin D(2) (PGD(2)), a major cyclooxygenase product in a variety of tissues, readily undergoes dehydration to yield the cyclopentenone-type PGs of the J(2) series, such as 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)), which have been suggested to exert anti-inflammatory effects in vivo. Meanwhile, the mechanism of these effects is not well understood and the natural site and the extent of its production in vivo remain unclear. In the present study, we raised a monoclonal antibody specific to 15d-PGJ(2) and determined its production in inflammation-related events. The monoclonal antibody (mAb11G2) was raised against the 15d-PGJ(2)-keyhole limpet hemocyanin conjugate and was found to recognize free 15d-PGJ(2) specifically. The presence of 15d-PGJ(2) in vivo was immunohistochemically verified in the cytoplasm of most of the foamy macrophages in human atherosclerotic plaques. In addition, the immunostaining of lipopolysaccharide-stimulated RAW264.7 macrophages with mAb11G2 demonstrated an enhanced intracellular accumulation of 15d-PGJ(2), suggesting that the PGD(2) metabolic pathway, generating the anti-inflammatory PGs, is indeed utilized in the cells during inflammation. The activation of macrophages also resulted in the extracellular production of PGD(2), which was associated with a significant increase in the extracellular 15d-PGJ(2) levels, and the extracellular 15d-PGJ(2) production was reproduced by incubating PGD(2) in a cell-free medium and in phosphate-buffered saline. Moreover, using a chiral high performance liquid chromatography method for separation of PGD(2) metabolites, we established a novel metabolic pathway, in which PGD(2) is converted to 15d-PGJ(2) via an albumin-independent mechanism.

Renal inflammation is a final common pathway of chronic kidney disease (CKD), and its progression can be used to effectively gauge the degree of renal dysfunction. Interleukin-1 (IL-1) receptor-associated kinase 4 (IRAK-4) has been reported to be a pivotal molecule for IL-1 receptor- and Toll-like receptor-induced signaling and activation of proinflammatory mediators. In this study, we hypothesized that if inflammation plays a key role in renal failure, then the anti-inflammatory effect of IRAK-4 inhibitor should be effective in improving CKD. To determine its pharmacological potency, we investigated the renoprotective properties of the novel IRAK-4 inhibitor AS2444697 (N-[3-carbamoyl-1-(tetrahydro-2H-pyran-4-yl)-1H-pyrazol-4-yl]-2-(2-methylpyridin-4-yl)-1,3-oxazole-4-carboxamide hydrochloride (1:1)) in 5/6 nephrectomized (Nx) rats, a model of CKD. Six weeks' repeated administration of AS2444697 (0.3-3 mg/kg, twice daily) dose-dependently and significantly reduced urinary protein excretion and prevented the development of glomerulosclerosis and interstitial fibrosis without affecting the blood pressure. In addition, AS2444697 showed beneficial effects on renal function as demonstrated by the decrease in levels of plasma creatinine and blood urea nitrogen and attenuation of decline in creatinine clearance. 5/6 Nx rats exhibited low-grade inflammation as evidenced by increased renal mRNA expression and plasma levels of proinflammatory cytokines (IL-1β, IL-6, TNF-α, and MCP-1) and C-reactive protein as a marker of systemic inflammation. AS2444697 significantly reduced or showed a decreasing trend in expression and levels of these inflammatory parameters. These results suggest that AS2444697 suppresses the progression of chronic renal failure via anti-inflammatory action and may therefore be potentially useful in treating CKD patients.

In the present study, we find that cyclopentenone prostaglandins (PGs) of the J(2) series, naturally occurring derivatives of PGD(2), are potential inducers of intracellular oxidative stress that mediates cell degeneration. Based on an extensive screening of diverse chemical agents on induction of intracellular production of reactive oxygen species (ROS), we found that the cyclopentenone PGs, such as PGA(2), PGJ(2), Delta(12)-PGJ(2), and 15-deoxy-Delta(12,14)-PGJ(2), showed the most potent pro-oxidant effect on SH-SY5Y human neuroblastoma cells. As the intracellular events that mediate the PG cytotoxicity, we observed (i) the cellular redox alteration represented by depletion of antioxidant defenses, such as glutathione and glutathione peroxidase; (ii) a transient decrease in the mitochondrial membrane potential (Deltapsi); (iii) the production of protein-bound lipid peroxidation products, such as acrolein and 4-hydroxy-2-nonenal; and (iv) the accumulation of ubiquitinated proteins. These events correlated well with the reduction in cell viability. In addition, the thiol compound, N-acetylcysteine, could significantly inhibit the PG-induced ROS production, thereby preventing cytotoxicity, suggesting that the redox alteration is closely related to the pro-oxidant effect of cyclopentenone PGs. More strikingly, the lipid peroxidation end products, acrolein and 4-hydroxy-2-nonenal, detected in the PG-treated cells potently induced the ROS production, which was accompanied by the accumulation of ubiquitinated proteins and cell death, suggesting that the membrane lipid peroxidation products may represent one of the causative factors that potentiate the cytotoxic effect of cyclopentenone PGs by accelerating intracellular oxidative stress. These data suggest that the intracellular oxidative stress, represented by ROS production/lipid peroxidation and redox alteration, may underlie the well documented biological effects, such as antiproliferative and antitumor activities, of cyclopentenone PGs.

Single- and multiple-dose studies were conducted to assess the pharmacokinetics, pharmacodynamics and safety of tolvaptan in healthy Japanese subjects.All studies were single-center, randomized, placebo-controlled, single-blind or double-blind. In an ascending single-dose study, subjects were given a single oral dose of 15-120 mg tolvaptan or placebo. In multiple-dose studies, subjects were given 30, 60, 90 or 120 mg tolvaptan or placebo once daily for 7 days.After a single dose of 15-120 mg tolvaptan, the maximum plasma concentration (C(max)) and the area under the plasma concentration-time curve from zero to time t (AUC(t)) increased dose-dependently, and increases in AUC(t) were dose-proportional. Increases in 24-hour cumulative urine volume were dose- and AUC(24hr)-dependent. Urine excretion rates reached a maximum within 2-4 h after dosing. The maximal urine excretion rates increased dose-dependently, and appeared to reach a plateau at doses ≥ 60 mg. A decrease in urine osmolality and an increase in free water clearance indicated an aquaretic effect of tolvaptan. Serum sodium concentrations were increased by tolvaptan and were higher than that with placebo, even 24 h after dosing, while serum potassium concentrations were unchanged. No tolvaptan accumulation was found after multiple dosing for 7 days. Although 24-hour cumulative urine volume following multiple dosing slightly decreased, a sustained diuretic effect was observed throughout the dosing period. The most common adverse event was mild thirst.Single and multiple oral doses of tolvaptan exhibited dose-dependent aquaretic effects. Tolvaptan was well tolerated at all doses tested.

The species selectivity of receptor antagonists often hinders their preclinical assessment in vivo. In order to evaluate human selective CC chemokine receptor type 5 (CCR5) antagonists in vivo, we generated human CCR5 transgenic mice that expressed the transgene on both peripheral blood leukocytes as well as thymocytes. The selective CCR5 ligand CC chemokine ligand 4 (CCL4)/macrophage inflammatory protein (MIP)-1beta induced the chemotaxis of thymocytes that had been derived from the transgenic mice, but not from littermate mice, suggesting that the human CCR5 expressed in the transgenic mice were functional. The binding of the human CCR5 specific antibody 45531 to peripheral blood granulocytes from the transgenic mice was inhibited by human selective CCR5 antagonist SCH-351125. Using this antibody, we developed an ex vivo assay system that is suitable for the evaluation of a test compound's ability to occupy the human CCR5 receptor on mouse peripheral blood leukocytes. This transgenic mouse model is useful for estimating the pharmacodynamics of human selective CCR5 antagonists in vivo.

Prostaglandin D 2 (PGD 2 ), a major cyclooxygenase product in a variety of tissues and cells, readily undergoes dehydration to yield the bioactive cyclopentenone-type PGs of the J 2 -series, such as 15-deoxy-Δ 12,14 -PGJ 2 (15d-PGJ 2 ). The observation that the level of 15d-PGJ 2 increased in the tissue cells from patients with sporadic amyotrophic lateral sclerosis suggested that the formation of 15d-PGJ 2 may be closely associated with neuronal cell death during chronic inflammatory processes. In vitro experiments using SH-SY5Y human neuroblastoma cells revealed that 15d-PGJ 2 induced apoptotic cell death. An oligonucleotide microarray analysis demonstrated that, in addition to the heat shock-responsive and redox-responsive genes, the p53-responsive genes, such as gadd45 , cyclin G1 , and cathepsin D , were significantly up-regulated in the cells treated with 15d-PGJ 2 . Indeed, the 15d-PGJ 2 induced accumulation and phosphorylation of p53, which was accompanied by a preferential redistribution of the p53 protein in the nuclei of the cells and by a time-dependent increase in p53 DNA binding activity, suggesting that p53 accumulated in response to the treatment with 15d-PGJ 2 was functional. The 15d-PGJ 2 -induced accumulation of p53 resulted in the activation of a death-inducing caspase cascade mediated by Fas and the Fas ligand.

Prostaglandin D(2) (PGD(2)), a major cyclooxygenase product in a variety of tissues, readily undergoes dehydration to yield the cyclopentenone-type PGs of the J(2) series, such as 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)), which have been suggested to exert anti-inflammatory effects in vivo. Meanwhile, the mechanism of these effects is not well understood and the natural site and the extent of its production in vivo remain unclear. In the present study, we raised a monoclonal antibody specific to 15d-PGJ(2) and determined its production in inflammation-related events. The monoclonal antibody (mAb11G2) was raised against the 15d-PGJ(2)-keyhole limpet hemocyanin conjugate and was found to recognize free 15d-PGJ(2) specifically. The presence of 15d-PGJ(2) in vivo was immunohistochemically verified in the cytoplasm of most of the foamy macrophages in human atherosclerotic plaques. In addition, the immunostaining of lipopolysaccharide-stimulated RAW264.7 macrophages with mAb11G2 demonstrated an enhanced intracellular accumulation of 15d-PGJ(2), suggesting that the PGD(2) metabolic pathway, generating the anti-inflammatory PGs, is indeed utilized in the cells during inflammation. The activation of macrophages also resulted in the extracellular production of PGD(2), which was associated with a significant increase in the extracellular 15d-PGJ(2) levels, and the extracellular 15d-PGJ(2) production was reproduced by incubating PGD(2) in a cell-free medium and in phosphate-buffered saline. Moreover, using a chiral high performance liquid chromatography method for separation of PGD(2) metabolites, we established a novel metabolic pathway, in which PGD(2) is converted to 15d-PGJ(2) via an albumin-independent mechanism.

Purpose: To elucidate the role of nitric oxide (NO) in the eye and the flicker-induced vascular response. Methods: The blood flow in the retina and different parts of the optic nerve was compared in cats treated with the NO-synthase blocker, NG-nitro-L-arginine methyl ester and in control animals. In both groups, one of the eyes was dark-adapted, the other was subjected to 8 Hz flickering light. The regional blood flow was measured with the microsphere method. Results: In control animals, flickering light increased blood flow in the retina and optic nerve head by 39% and 256%, respectively. Pretreatment with NG-nitro-L-arginine methyl ester prevented this increase in retinal blood flow and markedly reduced the blood flow in the optic nerve heads. Conclusion: NO release may mediate much of the vasodilating effect of flicker in cats, and play a role in maintaining normal vascular tone in the optic nerve head.

The two most widely industrialized techniques for aluminum refining are the three-layer electrolytic refining process and the segregation process. The three-layer process uses molten salt electrolysis to produce aluminum of greater than 99.99% purity. The segregation process produces aluminum of 99.98–99.99% purity. Although aluminum refined by the segregation process has a somewhat lower purity than that produced by the other methods, the segregation process has become increasing common since it consumes less energy. Ultrahigh-purity aluminum (99.9999%), which has uranium and thorium impurities reduced to less than 1 ppb, can also be produced.

歯口清掃による歯の動揺度の改善を, より客観的に評価することを日的として, 動揺度測定装置 (TMC-01) を考案し, 臨床応用を試みた。この装置は, 歯を水平方向に移動させるのに必要な荷重を連続量 (g) で表示するものである。外来患者20名 (被検歯総数216本) を対象に, 来院時毎に, 徹底した歯口清掃と歯間部の清掃を主日的とした刷掃指導を行った。動揺度は, 初診時, 2週, 4週, 8週後にTMC-01を用いて測定し, 同時にプラーク付着状態も診査した。その結果, (1) 動揺歯の荷重平均は, 初診時101g, 2週後141g, 4週後147g, 8週後157gであり, 短期間のうちに著明な改善が認められた。 (2) 2週後で74%, 8週後で85%の動揺歯に改善が認められた。 (3) 初診時, 79g以下の力で動揺を示した歯は, 2週以後の改善傾向が減少したが, 809以上の力で動揺を認めた歯は, 期間全体を通じて改善した。以上より今回用いた装置は, 動揺度の測定に応用できる可能性が示唆された。

The chemokine receptor CCR5 is an attractive target for HIV-1 drug development, as individuals whose cells lack surface CCR5 expression are highly resistant to HIV-1 infection. CCR5 ligands, such as CCL5/RANTES, effectively inhibit HIV-1 infection by competing for binding opportunities to the CCR5 and inducing its internalization. However, the inherent proinflammatory activity of the chemotactic response of CCR5 ligands has limited their clinical use. In this study, we found that a novel small molecule, functionally selective CCR5 agonist, 2,2-dichloro-1-(triphenylphosphonio)vinyl formamide perchlorate (YM-370749), down-modulates CCR5 from the cell surface without inducing a chemotactic response and inhibits HIV-1 replication. In molecular docking studies of YM-370749 and a three-dimensional model of CCR5 based on the rhodopsin crystal structure as well as binding and functional studies using various CCR5 mutants, the amino acid residues necessary for interaction with YM-370749 were marked. These results provide a structural basis for understanding the activation mechanism of CCR5 and for designing functionally selective agonists as a novel class of anti-HIV-1 agents.