In Guk Park

The development of predictive sequence-activity models capable of reliably identifying optimal antisense oligonucleotide (ASO) candidates across diverse target genes remains a central challenge in ASO drug discovery. Here, we curated a patent-derived data set of 59,273 gapmer ASOs (20-mer 5-10-5 MOE and 16-mer 3-10-3 cET) across 30 human genes and benchmarked gene-specific and cross-target prediction models using comprehensive sequence and target-context descriptors. Gene-specific models achieved strong predictive performance, with genomic context and sequence motifs as the most informative features. However, cross-target models evaluated by leave-one-gene-out cross-validation failed to generalize to new target genes, revealing that ASO activity is governed primarily by target-specific determinants. To address this limitation in data-scarce settings, we developed ASO-RASAR, a read-across sequence-activity relationship model that transfers predictive information from data-rich to data-poor target genes. In simulated low-data scenarios, the best ASO-RASAR strategy improved median AUPRC over standard QSAR baselines by up to 22.5%. Experimental validation using WFDC1-targeting ASOs in human bone marrow-derived mesenchymal stem cells supported that ASO-RASAR prediction scores correlated strongly with knockdown efficiency (Pearson's r = 0.83). These findings establish ASO-RASAR as a practical approach for prioritizing ASO candidates against novel targets with limited experimental data.

Androgenetic alopecia (AGA) is a common form of hair loss characterized by androgen-driven tissue remodeling, including progressive follicular miniaturization and dermal fibrosis, which is accompanied by low-grade immune activation. However, the molecular mechanisms underlying this fibroimmune dysfunction remain poorly understood. Dermal fibroblasts (DFs) have been suggested as androgen-responsive stromal cells and a potential source of CXCL12, a chemokine implicated in fibroimmune pathology, but their precise role in AGA has not been fully established. In this study, we performed single-cell transcriptomic profiling of a testosterone-induced mouse model of AGA, with or without treatment of CXCL12-neutralizing antibody, to elucidate the pathological role of CXCL12 in mediating stromal-immune interactions. Our analysis suggested that DFs are the primary androgen-responsive population driving CXCL12 expression. Autocrine CXCL12-ACKR3 signaling in DFs activated TGF-β pathways and promoted fibrotic extracellular matrix deposition. In parallel, paracrine CXCL12-CXCR4 signaling reprogrammed Sox2⁺Twist1⁺ dermal papilla cells (DPCs) and promoted the accumulation of pro-fibrotic Trem2⁺ macrophages, contributing to impaired hair follicle regeneration. Notably, CXCL12 blockade attenuated these stromal and immune alterations, restored the regenerative capacity of DPCs, reduced pro-fibrotic macrophage infiltration, and promoted hair regrowth. Together, these findings identify CXCL12 as a central mediator of androgen-induced fibroimmune remodeling and highlight its potential as a therapeutic target in AGA.

We have previously demonstrated that receptor-interacting serine threonine kinase 1 (RIPK1) is expressed in hair follicles and regulates the hair cycle. In a mouse model, RIPK1 inhibitors also accelerated the telogen-to-anagen transition and elongated the anagen period. Here, we first investigated the involvement of RIPK1 in alopecia areata (AA). The mRNA and protein expression of RIPK1 was increased in the skin of an AA mouse model. Single-cell RNA sequencing and immunohistochemistry showed that RIPK1 was highly increased in dendritic cells (DCs) and CD8⁺ T cells. RIPK1 inhibitors (i.e., Necrostatin-1s and GSK2982772) delayed the onset of AA in the mouse model and reduced the numbers of DCs and CD8⁺ T cells in AA skin. The RIPK1 inhibitors also increased the hair length in a mouse hair organ culture mimicking AA. Collectively, these results suggest that RIPK1 is involved in AA onset via modulating immune cells, and RIPK1 inhibitors could prevent AA onset.

We previously demonstrated that C-X-C Motif Chemokine Ligand 12 (CXCL12) is primarily secreted by dermal fibroblasts in response to androgens and induces hair miniaturization in the mouse androgenic alopecia (AGA) model. However, the direct effects of androgen-induced CXCL12 on dermal papilla cells (DPCs) and dermal sheath cup cells (DSCs) have not been demonstrated. First, we compared single-cell RNA sequencing data between mouse and human skin, and the results show that CXCL12 is highly co-expressed with the androgen receptor (AR) in the DPCs and DSCs of only human hair. Immunohistochemistry also showed that CXCL12 is co-expressed with the AR in the DPCs and DSCs of human hair follicles. In human hair organ culture, androgens also increased CXCL12 expression in DPCs and DSCs and reduced hair length, while the CXCL12 antibody increased hair length via AR inactivation. CXCL12 mRNA was upregulated by androgen treatment in primary human DPCs and DSCs. On the contrary, AR inhibitors or siRNA treatment reduced CXCL12 expression. Collectively, these results suggest that CXCL12 is co-expressed with the AR in the DPCs and DSCs of human hair follicles; therefore, inhibition of CXCL12 using antibodies is a promising strategy for AGA treatment.

We have previously demonstrated that receptor-interacting serine threonine kinase 1 (RIPK1) is expressed in hair follicle and regulates hair cycle. RIPK1 inhibitors also accelerated the telogen-to-anagen transition and elongated the anagen period in the mouse model. Here, we first investigated the involvement of RIPK1 in alopecia areata (AA). mRNA and protein expression of RIPK1 was increased in the skin of AA mouse model. Single cell RNA sequencing and immunohistochemistry showed that RIPK1 is highly increased in dendritic cells (DCs) and CD8+ T cells. RIPK1 inhibitors (i.e., Necrostatin-1s and GSK2982772) delayed the onset of AA in mouse model, and reduced the DCs and CD8+ T cells in AA skin. RIPK1 inhibitors also increased the hair length in the mouse hair organ culture mimicking AA. Collectively, these results suggest that RIPK1 is involved in AA onset via modulating immune cells, and RIPK1 inhibitors could prevent AA onset.

This study introduces a novel cheminformatic read-across approach designed to identify potential environmental obesogens, substances capable of disrupting metabolism and inducing obesity by mainly influencing nuclear hormone receptors (NRs). Leveraging real-valued two-dimensional features derived from chemical fingerprints of 8435 Tox21 compounds, cluster analysis and subsequent statistical testing revealed 385 clusters enriched with compounds associated with specific NR targets. Notably, one cluster exhibited selective enrichment in peroxisome proliferator-activated receptor γ (PPARγ) agonist activity, prominently featuring methoxy cinnamate ultraviolet (UV) filters and obesogen-related compounds. Experimental validation confirmed that 2-ethoxyethyl 4-methoxycinnamate, an organic UV filter cinoxate, could selectively bind to PPARγ (K_i = 18.0 μM), eliciting an obesogenic phenotype in human bone marrow-derived mesenchymal stem cells during adipogenic differentiation. Molecular docking and further experiments identified cinoxate as a potent PPARγ full agonist, demonstrating a preference for coactivator SRC3 recruitment. Moreover, cinoxate upregulated transcription levels of genes encoding lipid metabolic enzymes in normal human epidermal keratinocytes as primary cells exposed during clinical usage. This study provides compelling evidence for the efficacy of cheminformatic read-across analysis in prioritizing potential obesogens, showcasing its utility in unveiling cinoxate as an obesogenic PPARγ agonist.