Adapalene induces adipose browning through the RARβ-p38 MAPK-ATF2 pathway

Multidimensional role of adapalene in regulating cell death in multiple myeloma

Aims

Multiple myeloma (MM) remains a challenging condition to cure, with persistent drug resistance negating the benefits of treatment advancements. The unraveling complexities in programmed cell death (PCD), inclusive of apoptosis, autophagy, and ferroptosis, have highlighted novel therapeutic avenues. Our study focuses on deciphering how adapalene (ADA), a small molecule compound, accelerates the demise of MM cells via targeting their compensatory survival mechanisms.

Methods

To assess the impact of ADA on MM, we employed flow cytometry and trypan blue exclusion assays to determine cell viabilities across MM cell lines and primary patient samples post-treatment. To delineate ADA's therapeutic targets and mechanisms, we conducted RNA sequencing (RNA-seq), gene set enrichment analysis (GSEA), molecular docking, and molecular dynamics simulations. We further designed pre-clinical trials emphasizing MM, exploring the efficacy of ADA as a standalone and in combination with bortezomib (BTZ).

Results

ADA elicited a dose-responsive induction of MM cell death. Building upon ADA's anti-MM capabilities as a single agent, we proposed that ADA-BTZ co-treatment might amplify this lethality. Indeed, ADA and BTZ together greatly potentiated MM cell death. ADA proved beneficial in restoring BTZ susceptibility in BTZ-resistant relapsed or refractory MM (RRMM) patient cells. Molecular simulations highlighted ADA's high affinity (-9.17 kcal/mol) for CD138, with MM-GBSA revealing a binding free energy of -27.39 kcal/mol. Detailed interaction analyses indicated hydrogen-bonding of ADA with CD138 at the Asp35 and Gln34 residues. Additionally, ADA emerged as a versatile instigator of both ferroptosis and apoptosis in MM cells. Furthermore, ADA disrupted activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway triggered by BTZ, fostering cell death in BTZ-resistant MM subsets.

Conclusion

ADA demonstrates a comprehensive capability to orchestrate MM cell death, exerting pronounced anti-MM activity while disrupting NF-κB-related drug resistance. ADA sensitization of MM cells to BTZ unravels its potential as a novel therapeutic drug for MM management.

Involvement of Sep38β in the Insecticidal Activity of Bacillus thuringiensis against Beet Armyworm, Spodoptera exigua (Lepidoptera)

The p38 mitogen-activated protein kinases (MAPKs) are associated with insect immunity, tissue repair, and the insecticidal activity of Bacillus thuringiensis (Bt). Here, a p38 MAPK family gene (Sep38β) was identified from Spodoptera exigua. Among the developmental stages, the transcription level of Sep38β was the highest in egg, followed by that in prepupa and pupa. Sep38β expression peaked in Malpighian tubules and the hemolymph of fifth instar larvae. Knockdown of Sep38β or injection of SB203580 (a p38 MAPK inhibitor) significantly downregulated the SeDUOX expression and reactive oxygen species (ROS) level in the midgut, accounting for deterioration of the midgut to scavenge pathogens and enhancement of Bt insecticidal activity. In conclusion, all the results demonstrate that Sep38β regulates the immune-related ROS level in the insect midgut, which suppresses the insecticidal activity of Bt against S. exigua by 17-22%. Our study highlights that Sep38β is essential for insect immunity and the insecticidal activity of Bt to S. exigua and is a potential target for pest control.

2-phenylacetamide Separated from the seed of Lepidium apetalum Willd. inhibited renal fibrosis via MAPK pathway mediated RAAS and oxidative stress in SHR Rats

BACKGROUND

Renal fibrosis with Renin-angiotensin-aldosterone system (RAAS) activation and oxidative stress are one of the major complications in hypertension. 2-phenylacetamide (PA), a major active component of Lepidium apetalum Willd. (L.A), has numerous pharmacological effects. Its analogues have the effect of anti-renal fibrosis and alleviating renal injury. This study aims to explore the underlying mechanism of PA for regulating the renal fibrosis in SHR based on the MAPK pathway mediated RAAS and oxidative stress.

METHODS

The SHR rats were used as the hypertension model, and the WKY rats were used as the control group. The blood pressure (BP), urine volume were detected every week. After PA treatment for 4 weeks, the levels of RAAS, inflammation and cytokines were measured by Enzyme-Linked Immunosorbnent Assay (ELISA). Hematoxylin-Eosin staining (HE), Masson and Immunohistochemistry (IHC) were used to observe the renal pathology, collagen deposition and fibrosis. Western blot was used to examine the MAPK pathway in renal. Finally, the SB203580 (p38 MAPK inhibitor) antagonism assay in the high NaCl-induced NRK52e cells was used, together with In-Cell Western (ICW), Flow Cytometry (FCM), High Content Screening (HCS) and ELISA to confirm the potential pharmacological mechanism.

RESULTS

PA reduced the BP, RAAS, inflammation and cytokines, promoted the urine, and relieved renal pathological injury and collagen deposition, repaired renal fibrosis, decreased the expression of NADPH Oxidase 4 (NOX4), transforming growth factor-β (TGF-β), SMAD3 and MAPK signaling pathway in SHR rats. Meanwhile,,the role of PA could be blocked by p38 antagonist SB203580 effectively in the high NaCl-induced NRK52e cells. Moreover, molecular docking indicated that PA occupied the ligand binding sites of p38 MAPK.

CONCLUSION

PA inhibited renal fibrosis via MAPK signalling pathway mediated RAAS and oxidative stress in SHR Rats.

Leaf Extract of Perilla frutescens (L.) Britt Promotes Adipocyte Browning via the p38 MAPK Pathway and PI3K-AKT Pathway

The leaf of Perilla frutescens (L.) Britt (PF) has been reported to negatively affect adipocyte formation, inhibit body-fat formation, and lower body weight. However, its effect on adipocyte browning remains unknown. Thus, the mechanism of PF in promoting adipocyte browning was investigated. The ingredients of PF were acquired from the online database and filtered with oral bioavailability and drug-likeness criteria. The browning-related target genes were obtained from the Gene Card database. A Venn diagram was employed to obtain the overlapped genes that may play a part in PF promoting adipocyte browning, and an enrichment was analysis conducted based on these overlapped genes. A total of 17 active ingredients of PF were filtered, which may regulate intracellular receptor-signaling pathways, the activation of protein kinase activity, and other pathways through 56 targets. In vitro validation showed that PF promotes mitochondrial biogenesis and upregulates brite adipocyte-related gene expression. The browning effect of PF can be mediated by the p38 MAPK pathway as well as PI3K-AKT pathway. The study revealed that PF could promote adipocyte browning through multitargets and multipathways. An in vitro study validated that the browning effect of PF can be mediated by both the P38 MAPK pathway and the PI3K-AKT pathway.

Naringin promotes fat browning mediated by UCP1 activation via the AMPK signaling pathway in 3T3-L1 adipocytes

Induction of the brown adipocyte-like phenotype in white adipocytes (fat browning) is considered a promising therapeutic strategy to treat obesity. Naringin, a citrus flavonoid, has antioxidant, anti-inflammatory, and anticancer activities. We examined the application of naringin as an anti-obesity compound based on an investigation of its induction of fat browning in 3T3-L1 adipocytes. Naringin did not induce lipid accumulation in differentiated 3T3-L1 adipocytes. Additionally, naringin reduced the expression levels of proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα) involved in adipogenesis during lipid metabolism and increased the levels of PPARα and adiponectin involved in fatty acid oxidation. The expression levels of fat browning markers uncoupling protein 1 (UCP1; involved in thermogenesis) and PR domain containing 16 (PRDM16) increased. In addition, naringin treatment resulted in the activation of PPARγ coactivator 1-alpha (PGC-1α), a factor related to UCP1 transcription and mitochondrial biogenesis. Moreover, the expression of beige adipocyte-specific genes such as Cd137, Cited1, Tbx1, and Tmem26 was also induced. The small multi-lipid droplets characteristic of beige adipocytes indicated that naringin treatment increased the levels of all lipolysis markers (hormone-sensitive lipase [HSL], adipose triglyceride lipase [ATGL], perilipin [PLIN], and protein kinase A [PKA]). Adenosine monophosphate-activated protein kinase (AMPK) and UCP1 levels increased by treatment with naringin alone; this was possibly mediated by the stimulation of the AMPK signaling pathway. According to mechanistic studies, naringin activated the thermogenic protein UCP1 via the AMPK signaling pathway. In conclusion, naringin induces fat browning and is a promising therapeutic agent for metabolic disorders based on the regulation of lipid metabolism.