Hepatic TREM2+ macrophages express matrix metalloproteinases to control fibrotic scar formation.

Liver cirrhosis is characterized by the extensive deposition of extracellular matrix such as fibril collagen, causing dysfunction and failure of the liver. Hepatic macrophages play pivotal roles in the transition from inflammatory to restorative properties upon hepatic injury. In particular, scar-associated macrophages (SAMacs) control liver fibrosis with the representative expression of matrix metalloproteinase (MMP). However, the heterogenic SAMac population has not been well characterized yet. This study profiled heterogeneous liver macrophages using public databases of single-cell transcriptomics and found T-cell immunoglobulin and mucin containing (TIM)4- macrophages exhibited elevated expression of MMPs. Scar-associated triggering receptor expressed on myeloid cells (TREM)2 was positively correlated with MMP expression, suggesting that TREM2+ subsets exert their fibrotic role via MMPs. During the progression of diet-induced nonalcoholic steatohepatitis and drug-induced liver cirrhosis, monocyte-derived TREM2+ macrophages accumulate in the liver with the distinct expression of MMPs. A noticeable expansion of MMP- and TREM2- double positive macrophages was observed in fibrotic scar regions. Consistently, the analysis of single-cell transcriptomics for human cirrhotic livers supported the theory that TREM2+ SAMacs are strongly associated with MMPs. The results could expand the understanding of liver fibrosis and SAMac, offering potential therapeutic approaches for liver cirrhosis.

In vitro and in vivo suppression of SARS-CoV-2 replication by a modified, short, cell-penetrating peptide targeting the C-terminal domain of the viral spike protein.

Peptides are promising therapeutic agents for COVID-19 because of their specificity, easy synthesis, and ability to be fine-tuned. We previously demonstrated that a cell-permeable peptide corresponding to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike C-terminal domain (CD) inhibits the interaction between viral spike and nucleocapsid proteins that results in SARS-CoV-2 replication in vitro. Here, we used docking studies to design R-t-Spike CD(D), a more potent short cell-penetrating peptide composed of all D-form amino acids and evaluated its inhibitory effect against the replication of SARS-CoV-2 S clade and other variants. R-t-Spike CD(D) was internalized into Vero cells and Calu-3 cells and suppressed the replication of SARS-CoV-2 S clade, delta variant, and omicron variant with higher potency than the original peptide. In hemizygous K18-hACE2 mice, intratracheal administration of R-t-Spike CD(D) effectively delivered the peptide to the trachea and lungs, whereas intranasal administration delivered the peptide mostly to the upper respiratory system and stomach, and a small amount to the lungs. Administration by either route reduced viral loads in mouse lungs and turbinates. Furthermore, intranasally administered R-t-Spike CD(D) mitigated pathological change in the lungs and increased the survival of mice after infection with the SARS-CoV-2 S clade or delta variant. Our data suggest that R-t-Spike CD(D) has potential as a therapeutic agent against SARS-CoV-2 infection.

Computational Prediction of the Phenotypic Effect of Flavonoids on Adiponectin Biosynthesis.

In silico machine learning applications for phenotype-based screening have primarily been limited due to the lack of machine-readable data related to disease phenotypes. Adiponectin, a nuclear receptor (NR)-regulated adipocytokine, is relatively downregulated in human metabolic diseases. Here, we present a machine-learning model to predict the adiponectin-secretion-promoting activity of flavonoid-associated phytochemicals (FAPs). We modeled a structure-activity relationship between the chemical similarity of FAPs and their bioactivities using a random forest-based classifier, which provided the NR activity of each FAP as a probability. To link the classifier-predicted NR activity to the phenotype, we next designed a single-cell transcriptomics-based multiple linear regression model to generate the relative adiponectin score (RAS) of FAPs. In experimental validation, estimated RAS values of FAPs isolated from Scutellaria baicalensis exhibited a significant correlation with their adiponectin-secretion-promoting activity. The combined cheminformatics and bioinformatics approach enables the computational reconstruction of phenotype-based screening systems.

Alkaloids and Coumarins with Adiponectin-Secretion-Promoting Activities from the Leaves of Orixa japonica.

Fractionation of a methanol extract of Orixa japonica leaves led to the identification of five new quinoline alkaloids (1, 2, 4, 8, and 9), three new coumarins (15, 17, and 19), and 20 known compounds. The structures were determined by analysis of 1D and 2D NMR spectroscopic data. The absolute configuration of 19 was proposed by electronic circular dichroism calculation. Among the compounds tested in the phenotypic screening to measure adiponectin secretion in human bone marrow mesenchymal stem cells, metabolites 4 and 12 stimulated adiponectin secretions with EC50 values of 13.8 and 25.8 µM, respectively. Further PPARγ binding assay and molecular modeling suggested that compounds 4 and 12 are selective PPARγ agonists.

Galangin 3-benzyl-5-methylether derivatives function as an adiponectin synthesis-promoting peroxisome proliferator-activated receptor γ partial agonist.

The upregulation of adiponectin production has been suggested as a novel strategy for the treatment of metabolic diseases. Galangin, a natural flavonoid, exhibited adiponectin synthesis-promoting activity during adipogenesis in human bone marrow mesenchymal stem cells. In target identification, galangin bound both peroxisome proliferator-activated receptor (PPAR) γ and estrogen receptor (ER) ß. Novel galangin derivatives were synthesized to improve adiponectin synthesis-promoting compounds by increasing the PPARγ activity of galangin and reducing its ERß activity, because PPARγ functions can be inhibited by ERß. Three galangin 3-benzyl-5-methylether derivatives significantly promoted adiponectin production by 2.88-, 4.47-, and 2.76-fold, respectively, compared to the effect of galangin. The most potent compound, galangin 3-benzyl-5,7-dimethylether, selectively bound to PPARγ (Ki, 1.7 µM), whereas it did not bind to ERß. Galangin 3-benzyl-5,7-dimethylether was identified as a PPARγ partial agonist in docking and pharmacological competition studies, suggesting that it may have diverse therapeutic potential in a variety of metabolic diseases.

Adiponectin-Secretion-Promoting Cyclic Peptide-Polyketide Hybrids from a Halophyte-Associated Fungus, Colletotrichum gloeosporioides JS0417.

Three new cyclic peptide-polyketide hybrids (1-3) and two new chaetiacandin-type polyketides (4 and 5) along with nine known compounds were isolated from cultures of a halophyte-associated fungus, Colletotrichum gloeosporioides JS0417. Spectroscopic analysis revealed that 1-3 were cyclic depsipeptides where 3,5,11-trihydroxy-2,6-dimethyldodecanoic acid was linked to two amino acids through amide and ester bonds to form a 12-membered ring. Relative and absolute configurations for the peptides were determined with spectroscopic analysis and chemical reactions. The cyclic depsipeptides 2 and 6 were determined to act as strong adiponectin-secretion-promoting modulators with potential to treat metabolic diseases associated with hypoadiponectinemia. Notably, a known compound, tryptophol, significantly inhibited PGE2 synthesis and also promoted adiponectin secretion, exhibiting a similar biological activity profile to aspirin, but with greater potency. The presence of an isoleucine moiety and non-glycosylation may be important for biological activity of the cyclic peptide-polyketide hybrids, and non-methoxylation of the side chain may influence activity of the indole derivatives.

Discovery of Pan-peroxisome Proliferator-Activated Receptor Modulators from an Endolichenic Fungus, Daldinia childiae.

Adiponectin-synthesis-promoting compounds possess therapeutic potential to treat diverse metabolic diseases, including obesity and diabetes. Phenotypic screening to find adiponectin-synthesis-promoting compounds was performed using the adipogenesis model of human bone marrow mesenchymal stem cells. The extract of the endolichenic fungus Daldinia childiae 047215 significantly promoted adiponectin production. Bioactivity-guided isolation led to 13 active polyketides (1-13), which include naphthol monomers, dimers, and trimers. To the best of our knowledge, trimers of naphthol (1-4) have not been previously isolated as either natural or synthetic products. The novel naphthol trimer 3,1',3',3″-ternaphthalene-5,5',5″-trimethoxy-4,4',4″-triol (2) and a dimer, nodulisporin A (12), exhibited concentration-dependent adiponectin-synthesis-promoting activity (EC50 30.8 and 15.2 µM, respectively). Compounds 2 and 12 bound to all three peroxisome proliferator-activated receptor (PPAR) subtypes, PPARα, PPARγ, and PPARδ. In addition, compound 2 transactivated retinoid X receptor α, whereas 12 did not. Naphthol oligomers 2 and 12 represent novel pan-PPAR modulators and are potential pharmacophores for designing new therapeutic agents against hypoadiponectinemia-associated metabolic diseases.

Salicinoyl Quinic Acids and Their Prostaglandin E2 Production Inhibitory Activities from the Fruits of Casearia grewiifolia.

Phytochemical investigation on the dried fruits of Casearia grewiifolia led to the identification of 10 new salicinoyl quinic acid derivatives (1-10), a new benzoyl quinic acid (11), and two known compounds (12 and 13). The structures of the new compounds were elucidated by interpreting 1D and 2D NMR spectroscopic data including HMBC and EXSIDE along with a chemical method for sugar unit analysis. All isolates were evaluated for their inhibitory activities against prostaglandin E2 (PGE2) production in ultraviolet B (UVB)-irradiated HaCat keratinocytes. Of the isolates tested, compounds 6 and 12 were found to inhibit PGE2 production with IC50 values of 20.5 and 28.8 µM, respectively.

Arabidopsis TCX8 functions as a senescence modulator by regulating LOX2 expression.

KEY MESSAGE: TCX8 localizes to nucleus and has transcriptional repression activity. TCX8 binds to the promoter region of LOX2 encoding lipoxygenase, causing JA biosynthesis suppression, and thereby delays plant senescence. Conserved CXC domain-containing proteins are found in most eukaryotes. Eight TCX proteins, which are homologs of animal CXC-Hinge-CXC (CHC) proteins, were identified in Arabidopsis, and three of them, TSO1, TCX2/SOL2 and TCX3/SOL1, have been reported to affect cell-cycle control. TCX8, one of the TCX family proteins, was believed to be a TF but its precise function has not been reported. Yeast two-hybrid screening revealed TCP20, a TF that binds to the promoter of LOX2 encoding lipoxygenase, as a strong candidate for interaction with TCX8. We confirmed that TCX8 directly interacts with TCP20 using in vitro pull-down assay and in vivo BiFC and observed that TCX8, as a TF, localizes to nucleus. Using EMSA and by analyzing phenotypes of TCX8-overexpression lines, we demonstrated that TCX8 regulates the expression of LOX2 by binding to either cis-element of LOX2 promoter to which TCP20 or TCP4 binds, affecting JA biosynthesis, and thereby delaying plant senescence. Our study provides new information about the role of TCX8 in modulating plant senescence through regulating LOX2 expression.

Overexpression of AtBBD1, Arabidopsis Bifunctional Nuclease, Confers Drought Tolerance by Enhancing the Expression of Regulatory Genes in ABA-Mediated Drought Stress Signaling.

Drought is the most serious abiotic stress, which significantly reduces crop productivity. The phytohormone ABA plays a pivotal role in regulating stomatal closing upon drought stress. Here, we characterized the physiological function of AtBBD1, which has bifunctional nuclease activity, on drought stress. We found that AtBBD1 localized to the nucleus and cytoplasm, and was expressed strongly in trichomes and stomatal guard cells of leaves, based on promoter:GUS constructs. Expression analyses revealed that AtBBD1 and AtBBD2 are induced early and strongly by ABA and drought, and that AtBBD1 is also strongly responsive to JA. We then compared phenotypes of two AtBBD1-overexpression lines (AtBBD1-OX), single knockout atbbd1, and double knockout atbbd1/atbbd2 plants under drought conditions. We did not observe any phenotypic difference among them under normal growth conditions, while OX lines had greatly enhanced drought tolerance, lower transpirational water loss, and higher proline content than the WT and KOs. Moreover, by measuring seed germination rate and the stomatal aperture after ABA treatment, we found that AtBBD1-OX and atbbd1 plants showed significantly higher and lower ABA-sensitivity, respectively, than the WT. RNA sequencing analysis of AtBBD1-OX and atbbd1 plants under PEG-induced drought stress showed that overexpression of AtBBD1 enhances the expression of key regulatory genes in the ABA-mediated drought signaling cascade, particularly by inducing genes related to ABA biosynthesis, downstream transcription factors, and other regulatory proteins, conferring AtBBD1-OXs with drought tolerance. Taken together, we suggest that AtBBD1 functions as a novel positive regulator of drought responses by enhancing the expression of ABA- and drought stress-responsive genes as well as by increasing proline content.

CXCL14 downregulation in human keratinocytes is a potential biomarker for a novel in vitro skin sensitization test.

To elucidate the roles of epidermal keratinocytes in the toxicological outcomes of chemically induced contact dermatitis, genome-scale transcriptional analyses were performed using normal human keratinocytes (NHKCs) treated with 10 µM sodium lauryl sulfate (SLS) or 5 µM urushiol. In Gene Ontology (GO) enrichment analyses, SLS- and urushiol-induced upregulated DEGs are commonly associated with the regulation of pro-inflammatory responses and epidermal differentiation processes in NHKCs whereas cellular protein metabolic process was also identified as a commonly downregulated DEG signature. Among the downregulated DEGs, CXCL14 was investigated as a potential biomarker for a new in vitro skin sensitization test using OECD TG429 reference chemicals. CXCL14 was significantly downregulated in NHKCs in response to 62.5% of the OECD TG429 sensitizers in a concentration-dependent manner. When the sensitizer-induced upregulation of chemokine CXCL8 was included in the analysis, 87.5% of the OECD TG429 reference sensitizing chemicals significantly induced either CXCL8 upregulation or CXCL14 downregulation in NHKCs. Only one OECD TG429 reference non-sensitizer changed the constitutive CXCL14 expression in NHKCs whereas five out of six non-sensitizers altered CXCL8 production. The reference irritating non-sensitizer SLS caused a false-positive outcome. The downregulation of constitutively expressed CXCL14 was regulated by both the MAPK/ERK and JAK3/STAT6 pathways in NHKCs. CXCL14 can be used as a mechanism-based biomarker in the development of in vitro skin sensitization tests and may help improve the distinction between allergenic sensitizers and non-sensitizers.

Selenium bioisosteric replacement of adenosine derivatives promoting adiponectin secretion increases the binding affinity to peroxisome proliferator-activated receptor δ.

N6-(3-Iodobenzyl)adenosine-5'-N-methyluronamide (1a, IB-MECA) exhibited polypharmacological characteristics targeting A3 adenosine receptor (AR), peroxisome proliferator-activated receptor (PPAR) γ, and PPARδ, simultaneously. The bioisosteric replacement of oxygen in 4'-oxoadenosines with selenium significantly increased the PPARδ-binding activity. 2-Chloro-N6-(3-iodobenzyl)-4'-selenoadenosine-5'-N-methyluronamide (3e) and related 4'-selenoadenosine derivatives significantly enhanced adiponectin biosynthesis during adipogenesis in human bone marrow mesenchymal stem cells (hBM-MSCs). The PPARδ-binding affinity, but not the A3 AR binding affinity, of 4'-selenoadenosine derivatives correlated with their adiponectin secretion stimulation. Compared with the sugar ring of 4'-oxoadenosine, that of 4'-selenoadenosine was more favorable in forming the South sugar conformation. In the molecular docking simulation, the South sugar conformation of compound 3e formed additional hydrogen bonds inside the PPARδ ligand-binding pocket compared with the North conformation. Therefore, the sugar conformation of 4'-selenoadenosine PPAR modulators affects the ligand binding affinity against PPARδ.

2-Phenyl-8-(1-phenylallyl)-chromenone compounds have a pan-PPAR modulator pharmacophore.

Adiponectin is an adipocytokine with insulin-sensitizing, anti-atherogenic, and anti-inflammatory properties. Adiponectin secretion-inducing compounds have therapeutic potential in a variety of metabolic diseases. Phenotypic screening led to the discovery that 5,7-dihydroxy-8-(1-(4-hydroxy-3-methoxyphenyl)allyl)-2-phenyl-4H-chromen-4-one (compound 1) had adiponectin secretion-inducing activity during adipogenesis in human bone marrow mesenchymal stem cells (hBM-MSCs). Compound 1 was originally reported to be an anti-cancer chemical isolated from natural honeybee propolis, and its adiponectin secretion-inducing activity was found in non-cytotoxic concentrations. In a target identification study, compound 1 and its potent synthetic derivative compound 5 were shown to be novel pan-peroxisome proliferator-activator receptor (PPAR) modulators. Molecular docking models with PPARs have indicated that the binding modes of chromenone compounds preferentially interacted with the hydrophobic ligand binding pocket of PPARs. In addition, chromenone compounds have been shown to result in different phenotypic outcomes in the transcriptional regulation of lipid metabolic enzymes than those of selective PPAR mono-agonists for PPARα, PPARγ, and PPARδ. In line with the pharmacology of adiponectin and PPAR pan-modulators, compounds 1 and 5 may have diverse therapeutic potentials to treat cancer and metabolic diseases.

Adiponectin-Secretion-Promoting Phenylethylchromones from the Agarwood of Aquilaria malaccensis.

The therapeutic potential of adiponectin regulation has received interest because of its association with diverse human disease conditions, such as diabetes, obesity, atherosclerosis, and cancer. Phenylethylchromone derivatives from Aquilaria malaccensis-derived agarwood promoted adiponectin secretion during adipogenesis in human bone marrow mesenchymal stem cells, and 5,6-dihydroxy-2-(2-phenylethyl)chromone (1) was identified as a new chromone derivative. A target identification study with the most potent adiponectin-secretion-promoting phenylethylchromones, 6-methoxy-2-(2-phenylethyl)chromone (3) and 7-methoxy-2-(2-phenylethyl)chromone (4), showed that they are PPARγ partial agonists. Therefore, the diverse therapeutic effects of agarwood are associated with a PPARγ-mediated adiponectin-secretion-promoting mechanism.

A long-wave UVA filter avobenzone induces obesogenic phenotypes in normal human epidermal keratinocytes and mesenchymal stem cells.

Avobenzone is the most commonly used ultraviolet (UV) A filter ingredient in sunscreen. To investigate the biological activity of avobenzone in normal human epidermal keratinocytes (NHEKs), the genome-scale transcriptional profile of NHEKs was performed. In this microarray study, we found 273 up-regulated and 274 down-regulated differentially expressed genes (DEGs) in NHEKs treated with avobenzone (10 µM). Gene Ontology (GO) enrichment analysis showed that avobenzone significantly increased the DEGs associated with lipid metabolism in NHEKs. In addition, avobenzone increased the gene transcription of peroxisome proliferator-activated receptor γ (PPARγ) and fatty acid binding protein 4 in NHEKs, implicating that avobenzone may be one of the metabolic disrupting obesogens. To confirm the obesogenic potential, we examined the effect of avobenzone on adipogenesis in human bone marrow mesenchymal stem cells (hBM-MSCs). Avobenzone (EC50, 14.1 µM) significantly promoted adipogenesis in hBM-MSCs as its positive control obesogenic chemicals. Avobenzone (10 µM) significantly up-regulated mRNA levels of PPARγ during adipogenesis in hBM-MSCs. However, avobenzone did not directly bind to PPARγ and the avobenzone-induced adipogenesis-promoting activity was not affected by PPARγ antagonists T0070907 and GW9662. Therefore, avobenzone promoted adipogenesis in hBM-MSCs through a PPARγ-independent mechanism. This study suggests that avobenzone functions as a metabolic disrupting obesogen.

Keratinocyte-derived IL-36γ plays a role in hydroquinone-induced chemical leukoderma through inhibition of melanogenesis in human epidermal melanocytes.

Chemical leukoderma is an acquired type of vitiligo that can be initiated by various exogenous chemicals such as hydroquinone (HQ), rhododendrol (RD), or 4-tertiary butyl phenol (4-TBP). Despite the importance of epidermal keratinocytes in diverse dermatological conditions, their toxicological role in chemical leukoderma is poorly understood. To elucidate their role in the pathogenesis of chemical leukoderma, genome-scale transcriptional analysis was performed in human epidermal keratinocytes (HEKs) treated with a sub-cytotoxic HQ concentration (10 µM). The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway-based functional enrichment analysis of HQ-induced differentially expressed genes (DEGs) revealed that HQ significantly upregulated DEGs related to the IL-17 signaling pathway and significantly downregulated DEGs associated with melanogenesis in HEKs. The meta-analysis between the HQ-induced and cytokine-induced transcriptional data (GSE53751) showed that 58 DEGs were commonly upregulated between HQ- and IL-17A-treated HEKs. Notably, the expression of IL36G was significantly increased in HEKs in response to both HQ and IL-17A. IL-36γ (2 µg/ml) directly inhibits melanin biosynthesis in cultured human epidermal melanocytes (HEMs) and downregulates the gene transcription of key enzymes in the melanogenesis pathway including TYR, DCT, and TYRP1. Moreover, IL-36γ autocrinally regulated keratinocyte function to produce the proinflammatory cytokines IL-36γ, IL-6, and CXCL8/IL-8 in a concentration-dependent manner, suggesting that IL-36γ may stimulate the amplification cycle of cutaneous inflammation. In this regard, hydroquinone-induced IL-36γ from human keratinocytes plays a pivotal role in the development of chemical leukoderma by autocrinally or paracrinally modulating the crosstalk between keratinocytes and melanocytes.

Phenalenones from a Marine-Derived Fungus Penicillium Sp.

Six new phenalenone derivatives (1⁻6), along with five known compounds (7⁻11) of the herqueinone class, were isolated from a marine-derived fungus Penicillium sp. The absolute configurations of these compounds were assigned based on chemical modifications and their specific rotations. 4-Hydroxysclerodin (6) and an acetone adduct of a triketone (7) exhibited moderate anti-angiogenetic and anti-inflammatory activities, respectively, while ent-peniciherqueinone (1) and isoherqueinone (9) exhibited moderate abilities to induce adipogenesis without cytotoxicity.

Phosphodiesterase 4B plays a role in benzophenone-3-induced phototoxicity in normal human keratinocytes.

Benzophenone-3 (BP-3), which is extensively used in organic sunscreen, has phototoxic potential in human skin. Phosphodiesterase 4B (PDE4B) has a well-established role in inflammatory responses in immune cells. Currently, it is unknown if PDE4B is associated with BP-3-induced phototoxicity in normal human keratinocytes (NHKs). We found that BP-3 significantly increased PDE4B expression in ultraviolet B (UVB)-irradiated NHKs. Notably, BP-8, a sunscreen agent that shares the 2-hydroxy-4-methoxyphenyl methanone moiety with BP-3, also upregulated PDE4B expression in NHKs. Upon UVB irradiation, BP-3 upregulated the expression of pro-inflammatory factors, such as prostaglandin endoperoxide synthase 2, tumor necrosis factor α, interleukin 8, and S100A7, and downregulated the level of cornified envelope associated proteins, which are important in the development of the epidermal permeability barrier. The additive effects of UVB-activated BP-3 on the expression of both pro-inflammatory mediators and cornified envelope associated proteins were antagonized by treatment with the PDE4 inhibitor rolipram. The BP-3 and UVB co-stimulation-induced PDE4B upregulation and its association with the upregulation of pro-inflammatory mediators and the downregulation of epidermal differentiation markers were confirmed in a reconstituted three dimensional human epidermis model. Therefore, PDE4B has a role in the mechanism of BP-3-induced phototoxicity.

2-Formyl-komarovicine promotes adiponectin production in human mesenchymal stem cells through PPARγ partial agonism.

Adiponectin is a major adipocytokine secreted from mammalian adipocytes. Relatively low expression of adiponectin is associated with various human metabolic diseases and some cancers. Adiponectin-secreting compounds have therapeutic potential for these diseases. Adipogenesis of human bone marrow-mesenchymal stem cells (hBM-MSCs) has been used as a phenotypic assay to find adiponectin secreting compounds. In a phytochemical library screen, 2-formyl-komarovicine, 1-(quinolin-8-yl)-1,3,4,9-tetrahydro-2H-pyrido[3,4-b]indole-2-carbaldehyde, isolated from Nitraria komarovii was identified as a potential adiponectin-secreting compound. To validate the results of the impure phytochemical, we synthesized 2-formyl-komarovicine. The synthetic 2-formyl-komarovicine significantly promoted adiponectin production during adipogenesis in hBM-MSCs. In a target identification experiment, 2-formyl-komarovicine bound to peroxisome proliferator-activated receptor γ (PPARγ) in a concentration-dependent manner. Notably, 2-formyl-komarovicine competitively inhibited the adiponectin-promoting activity of a full PPARγ agonist, troglitazone, in hBM-MSCs, which is a pharmacological feature of a partial agonist. The ligand-docking model showed that 2-formyl-komarovicine interacted with the hydrophobic pocket of the PPARγ ligand-binding domain, but lacked an interaction to stabilize helix H12, which is one of the major binding themes of PPARγ partial agonists. We concluded that 2-formyl-komarovicine provides a novel pharmacophore for PPARγ partial agonists to increase adiponectin production.

Kojyl cinnamate esters are peroxisome proliferator-activated receptor α/γ dual agonists.

Adiponectin is an adipocytokine with insulin-sensitizing, anti-inflammatory, anti-atherosclerotic, and anti-aging properties. Compounds with the ability to promote adiponectin secretion are of interest for the development of anti-aging drugs to improve skin-aging phenotypes. In the phenotypic assay to measure adiponectin secretion during adipogenesis in human adipose tissue-derived mesenchymal stem cells (hAT-MSCs), kojyl cinnamate ester derivatives increased adiponectin secretion. A target identification study showed that the kojyl cinnamate ester derivatives competitively bound to peroxisome proliferator-activated receptor α/γ (PPARα/γ). The upregulation of adiponectin production induced by kojyl cinnamate ester derivatives was significantly correlated with PPARα and PPARγ binding activities. Kojyl cinnamate ester derivatives significantly increased the transcription of genes encoding cholesterol and fatty acid synthesizing enzymes in hAT-MSCs. Notably, the kojyl cinnamate esters upregulated the gene transcription of lipid metabolic enzymes in human epidermal keratinocytes, which are important in the integrity of skin permeability barrier. In addition, the kojyl cinnamate esters that function as PPARα/γ dual modulators inhibited ultraviolet B irradiation-induced inflammation in human epidermal keratinocytes. Therefore, kojyl cinnamate ester derivatives are a novel class of PPARα/γ dual agonists with the potential to improve skin-aging phenotypes.