A novel sphingosylphosphorylcholine and sphingosine-1-phosphate receptor 1 antagonist, KRO-105714, for alleviating atopic dermatitis

Sae-Bom Yoon ^# 1, Chang Hoon Lee ^# 1, Hyun Young Kim ¹, Daeyoung Jeong ¹, Moon Kook Jeon ¹, Sun-A Cho ², Kwangmi Kim ³, Taeho Lee ⁴, Jung Yoon Yang ¹, Young-Dae Gong ⁵, Heeyeong Cho ^1 6

PMID: 32514255, DOI: 10.1186/s12950-020-00244-6

Abstract

Background: Atopic dermatitis (eczema) is a type of inflammation of the skin, which presents with itchy, red, swollen, and cracked skin. The high global incidence of atopic dermatitis makes it one of the major skin diseases threatening public health. Sphingosylphosphorylcholine (SPC) and sphingosine-1-phosphate (S1P) act as pro-inflammatory mediators, as an angiogenesis factor and a mitogen in skin fibroblasts, respectively, both of which are important biological responses to atopic dermatitis. The SPC level is known to be elevated in atopic dermatitis, resulting from abnormal expression of sphingomyelin (SM) deacylase, accompanied by a deficiency in ceramide. Also, S1P and its receptor, sphingosine-1-phosphate receptor 1 (S1P1) are important targets in treating atopic dermatitis.

Results: In this study, we found a novel antagonist of SPC and S1P1, KRO-105714, by screening 10,000 compounds. To screen the compounds, we used an SPC-induced cell proliferation assay based on a high-throughput screening (HTS) system and a human S1P1 protein-based [³⁵S]-GTPγS binding assay. In addition, we confirmed the inhibitory effects of KRO-105714 on atopic dermatitis through related cell-based assays, including a tube formation assay, a cell migration assay, and an ELISA assay on inflammatory cytokines. Finally, we confirmed that KRO-105714 alleviates atopic dermatitis symptoms in a series of mouse models.

Conclusions: Taken together, our data suggest that SPC and S1P1 antagonist KRO-105714 has the potential to alleviate atopic dermatitis.

Keywords: Antagonist; Anti-inflammatory; Atopic dermatitis; High-throughput screening; Sphingosine-1-phosphate receptor 1; Sphingosylphosphorylcholine.

Presenter: Song Da-Eun

J Invest Dermatol. 2022 Mar;142(3 Pt A):594-602. doi: 10.1016/j.jid.2021.07.178.Epub 2021 Sep 1.

Specific β-Defensins Stimulate Pruritus through Activation of Sensory Neurons

Pang-Yen Tseng ¹, Mark A Hoon ²

• PMID: 34480893
• DOI: 10.1016/j.jid.2021.07.178

Abstract

Pruritus is a common symptom of dermatological disorders and has a major negative impact on QOL. Previously, it was suggested that human β-defensin peptides elicit itch through the activation of mast cells. In this study, we investigated in more detail the mechanisms by which β-defensins induce itch by defining the receptors activated by these peptides in humans and mice, by establishing their action in vivo, and by examining their expression in inflammatory dermal diseases. We found that elevated expression of DEFB103 is highly correlated with skin lesions in psoriasis and atopic dermatitis. We showed that the peptide encoded by this gene and related genes activate Mas-related G protein-coupled receptors with different potencies that are related to their charge density. Furthermore, we establish that although these peptides can activate mast cells, they also activate sensory neurons, with the former cells being dispensable for itch reactions in mice. Together, our studies highlight that specific β-defensins are likely endogenous pruritogens that can directly stimulate sensory neurons.

Presenter: Lee Gi-Baek

J Med Chem. 2022 Feb 24;65(4):3218-3228. doi: 10.1021/acs.jmedchem.1c01709.Epub 2022 Feb 4.

Thieno[2,3- d]pyrimidine-Based Positive Allosteric Modulators of Human Mas-Related G Protein-Coupled Receptor X1 (MRGPRX1)

Ilyas Berhane, Niyada Hin, Ajit G Thomas, Qian Huang, Chi Zhang, Vijayabhaskar Veeravalli, Ying Wu, Justin Ng, Jesse Alt, Camilo Rojas, Hiroe Hihara ¹, Mika Aoki ¹, Kyoko Yoshizawa ¹, Tomoki Nishioka ¹, Shuichi Suzuki ¹, Shao-Qiu He, Qi Peng, Yun Guan, Xinzhong Dong, Srinivasa N Raja, Barbara S Slusher, Rana Rais, Takashi Tsukamoto

• PMID: 35119273
• DOI: 10.1021/acs.jmedchem.1c01709

Abstract

Mas-related G protein-coupled receptor X1 (MRGPRX1) is a human sensory neuron-specific receptor and potential target for the treatment of pain. Positive allosteric modulators (PAMs) of MRGPRX1 have the potential to preferentially activate the receptors at the central terminals of primary sensory neurons and minimize itch side effects caused by peripheral activation. Using a high-throughput screening (HTS) hit, a series of thieno[2,3-d]pyrimidine-based molecules were synthesized and evaluated as human MRGPRX1 PAMs in HEK293 cells stably transfected with human MrgprX1 gene. An iterative process to improve potency and metabolic stability led to the discovery of orally available 6-(tert-butyl)-5-(3,4-dichlorophenyl)-4-(2-(trifluoromethoxy)phenoxy)thieno[2,3-d]pyrimidine (1t), which can be distributed to the spinal cord, the presumed site of action, following oral administration. In a neuropathic pain model induced by sciatic nerve chronic constriction injury (CCI), compound 1t(100 mg/kg, po) reduced behavioral heat hypersensitivity in humanized MRGPRX1 mice, demonstrating the therapeutic potential of MRGPRX1 PAMs in treating neuropathic pain.

Exploring neuronal mechanisms involved in the scratching behavior of a mouse model of allergic contact dermatitis by transcriptomics

Boyu Liu, Ruixiang Chen, Jie Wang, Yuanyuan Li, Chengyu Yin, Yan Tai, Huimin Nie, Danyi Zeng, Junfan Fang, Junying Du, Yi Liang, Xiaomei Shao, Jianqiao Fang , Boyi Liu 

Abstract

Background: Allergic contact dermatitis (ACD) is a common skin condition characterized by contact hypersensitivity to allergens, accompanied with skin inflammation and a mixed itch and pain sensation. The itch and pain dramatically affects patients’ quality of life. However, still little is known about the mechanisms triggering pain and itch sensations in ACD.

Methods: We established a mouse model of ACD by sensitization and repetitive challenge with the hapten oxazolone. Skin pathological analysis, transcriptome RNA sequencing (RNA-seq), qPCR, Ca²⁺ imaging, immunostaining, and behavioral assay were used for identifying gene expression changes in dorsal root ganglion innervating the inflamed skin of ACD model mice and for further functional validations.

Results: The model mice developed typical ACD symptoms, including skin dryness, erythema, excoriation, edema, epidermal hyperplasia, inflammatory cell infiltration, and scratching behavior, accompanied with development of eczematous lesions. Transcriptome RNA-seq revealed a number of differentially expressed genes (DEGs), including 1436-DEG mRNAs and 374-DEG-long noncoding RNAs (lncRNAs). We identified a number of DEGs specifically related to sensory neuron signal transduction, pain, itch, and neuroinflammation. Comparison of our dataset with another published dataset of atopic dermatitis mouse model identified a core set of genes in peripheral sensory neurons that are exclusively affected by local skin inflammation. We further found that the expression of the pain and itch receptor MrgprD was functionally upregulated in dorsal root ganglia (DRG) neurons innervating the inflamed skin of ACD model mice. MrgprD activation induced by its agonist β-alanine resulted in exaggerated scratching responses in ACD model mice compared with naïve mice.

Conclusions: We identified the molecular changes and cellular pathways in peripheral sensory ganglia during ACD that might participate in neurogenic inflammation, pain, and itch. We further revealed that the pain and itch receptor MrgprD is functionally upregulated in DRG neurons, which might contribute to peripheral pain and itch sensitization during ACD. Thus, targeting MrgprD may be an effective method for alleviating itch and pain in ACD.

Keywords: Allergic contact dermatitis; Itch; Pain; RNA-seq; Sensory neurons.

The online version contains supplementary material available at https://cmbl.biomedcentral.com/articles/10.1186/s11658-022-00316-w