Multi-organ Site Metastatic Reactivation Mediated by Non-canonical Discoidin Domain Receptor 1 Signaling.

Genetic screening identifies the atypical tetraspanin TM4SF1 as a strong mediator of metastatic reactivation of breast cancer. Intriguingly, TM4SF1 couples the collagen receptor tyrosine kinase DDR1 to the cortical adaptor syntenin 2 and, hence, to PKCα. The latter kinase phosphorylates and activates JAK2, leading to the activation of STAT3. This non-canonical mechanism of signaling induces the expression of SOX2 and NANOG; sustains the manifestation of cancer stem cell traits; and drives metastatic reactivation in the lung, bone, and brain. Bioinformatic analyses and pathological studies corroborate the clinical relevance of these findings. We conclude that non-canonical DDR1 signaling enables breast cancer cells to exploit the ubiquitous interstitial matrix component collagen I to undergo metastatic reactivation in multiple target organs.

Epigenetic Activation of WNT5A Drives Glioblastoma Stem Cell Differentiation and Invasive Growth.

Glioblastoma stem cells (GSCs) are implicated in tumor neovascularization, invasiveness, and therapeutic resistance. To illuminate mechanisms governing these hallmark features, we developed a de novo glioblastoma multiforme (GBM) model derived from immortalized human neural stem/progenitor cells (hNSCs) to enable precise system-level comparisons of pre-malignant and oncogene-induced malignant states of NSCs. Integrated transcriptomic and epigenomic analyses uncovered a PAX6/DLX5 transcriptional program driving WNT5A-mediated GSC differentiation into endothelial-like cells (GdECs). GdECs recruit existing endothelial cells to promote peritumoral satellite lesions, which serve as a niche supporting the growth of invasive glioma cells away from the primary tumor. Clinical data reveal higher WNT5A and GdECs expression in peritumoral and recurrent GBMs relative to matched intratumoral and primary GBMs, respectively, supporting WNT5A-mediated GSC differentiation and invasive growth in disease recurrence. Thus, the PAX6/DLX5-WNT5A axis governs the diffuse spread of glioma cells throughout the brain parenchyma, contributing to the lethality of GBM.

An atlas of epithelial cell states and plasticity in lung adenocarcinoma.

Understanding the cellular processes that underlie early lung adenocarcinoma (LUAD) development is needed to devise intervention strategies1. Here we studied 246,102 single epithelial cells from 16 early-stage LUADs and 47 matched normal lung samples. Epithelial cells comprised diverse normal and cancer cell states, and diversity among cancer cells was strongly linked to LUAD-specific oncogenic drivers. KRAS mutant cancer cells showed distinct transcriptional features, reduced differentiation and low levels of aneuploidy. Non-malignant areas surrounding human LUAD samples were enriched with alveolar intermediate cells that displayed elevated KRT8 expression (termed KRT8+ alveolar intermediate cells (KACs) here), reduced differentiation, increased plasticity and driver KRAS mutations. Expression profiles of KACs were enriched in lung precancer cells and in LUAD cells and signified poor survival. In mice exposed to tobacco carcinogen, KACs emerged before lung tumours and persisted for months after cessation of carcinogen exposure. Moreover, they acquired Kras mutations and conveyed sensitivity to targeted KRAS inhibition in KAC-enriched organoids derived from alveolar type 2 (AT2) cells. Last, lineage-labelling of AT2 cells or KRT8+ cells following carcinogen exposure showed that KACs are possible intermediates in AT2-to-tumour cell transformation. This study provides new insights into epithelial cell states at the root of LUAD development, and such states could harbour potential targets for prevention or intervention.

Antitelomerase therapy provokes ALT and mitochondrial adaptive mechanisms in cancer.

To assess telomerase as a cancer therapeutic target and determine adaptive mechanisms to telomerase inhibition, we modeled telomerase reactivation and subsequent extinction in T cell lymphomas arising in Atm(-/-) mice engineered with an inducible telomerase reverse transcriptase allele. Telomerase reactivation in the setting of telomere dysfunction enabled full malignant progression with alleviation of telomere dysfunction-induced checkpoints. These cancers possessed copy number alterations targeting key loci in human T cell lymphomagenesis. Upon telomerase extinction, tumor growth eventually slowed with reinstatement of telomere dysfunction-induced checkpoints, yet growth subsequently resumed as tumors acquired alternative lengthening of telomeres (ALT) and aberrant transcriptional networks centering on mitochondrial biology and oxidative defense. ALT+ tumors acquired amplification/overexpression of PGC-1ß, a master regulator of mitochondrial biogenesis and function, and they showed marked sensitivity to PGC-1ß or SOD2 knockdown. Genetic modeling of telomerase extinction reveals vulnerabilities that motivate coincidental inhibition of mitochondrial maintenance and oxidative defense mechanisms to enhance antitelomerase cancer therapy.

Telomerase reactivation following telomere dysfunction yields murine prostate tumors with bone metastases.

To determine the role of telomere dysfunction and telomerase reactivation in generating pro-oncogenic genomic events and in carcinoma progression, an inducible telomerase reverse transcriptase (mTert) allele was crossed onto a prostate cancer-prone mouse model null for Pten and p53 tumor suppressors. Constitutive telomerase deficiency and associated telomere dysfunction constrained cancer progression. In contrast, telomerase reactivation in the setting of telomere dysfunction alleviated intratumoral DNA-damage signaling and generated aggressive cancers with rearranged genomes and new tumor biological properties (bone metastases). Comparative oncogenomic analysis revealed numerous recurrent amplifications and deletions of relevance to human prostate cancer. Murine tumors show enrichment of the TGF-ß/SMAD4 network, and genetic validation studies confirmed the cooperative roles of Pten, p53, and Smad4 deficiencies in prostate cancer progression, including skeletal metastases. Thus, telomerase reactivation in tumor cells experiencing telomere dysfunction enables full malignant progression and provides a mechanism for acquisition of cancer-relevant genomic events endowing new tumor biological capabilities.

Oncogenic Kras maintains pancreatic tumors through regulation of anabolic glucose metabolism.

Tumor maintenance relies on continued activity of driver oncogenes, although their rate-limiting role is highly context dependent. Oncogenic Kras mutation is the signature event in pancreatic ductal adenocarcinoma (PDAC), serving a critical role in tumor initiation. Here, an inducible Kras(G12D)-driven PDAC mouse model establishes that advanced PDAC remains strictly dependent on Kras(G12D) expression. Transcriptome and metabolomic analyses indicate that Kras(G12D) serves a vital role in controlling tumor metabolism through stimulation of glucose uptake and channeling of glucose intermediates into the hexosamine biosynthesis and pentose phosphate pathways (PPP). These studies also reveal that oncogenic Kras promotes ribose biogenesis. Unlike canonical models, we demonstrate that Kras(G12D) drives glycolysis intermediates into the nonoxidative PPP, thereby decoupling ribose biogenesis from NADP/NADPH-mediated redox control. Together, this work provides in vivo mechanistic insights into how oncogenic Kras promotes metabolic reprogramming in native tumors and illuminates potential metabolic targets that can be exploited for therapeutic benefit in PDAC.

Alternative splicing of lncRNA LAIR fine-tunes the regulation of neighboring yield-related gene LRK1 expression in rice.

The diversity in alternative splicing of long noncoding RNAs (lncRNAs) poses a challenge for functional annotation of lncRNAs. Moreover, little is known on the effects of alternatively spliced lncRNAs on crop yield. In this study, we cloned nine isoforms resulting from the alternative splicing of the lncRNA LAIR in rice. The LAIR isoforms are generated via alternative 5'/3' splice sites and different combinations of specific introns. All LAIR isoforms activate the expression of the neighboring LRK1 gene and enhance yield-related rice traits. In addition, there are slight differences in the binding ability of LAIR isoforms to the epigenetic modification-related proteins OsMOF and OsWDR5, which affect the enrichment of H4K16ac and H3K4me3 at the LRK1 locus, and consequently fine-tune the regulation of LRK1 expression and yield-related traits. These differences in binding may be caused by polymorphic changes to the RNA secondary structure resulting from alternative splicing. It was also observed that the composition of LAIR isoforms was sensitive to abiotic stress. These findings suggest that the alternative splicing of LAIR leads to the formation of a functional transcript population that precisely regulates yield-related gene expression, which may be relevant for phenotypic polymorphism-based crop breeding under changing environmental conditions.

AUXIN RESPONSE FACTOR7 integrates gibberellin and auxin signaling via interactions between DELLA and AUX/IAA proteins to regulate cambial activity in poplar.

Cambial development in the stems of perennial woody species is rigorously regulated by phytohormones. Auxin and gibberellin (GA) play crucial roles in stimulating cambial activity in poplar (Populus spp.). In this study, we show that the DELLA protein REPRESSOR of ga1-3 Like 1 (RGL1), AUXIN RESPONSE FACTOR 7 (ARF7), and Aux/INDOLE-3-ACETIC ACID 9 (IAA9) form a ternary complex that mediates crosstalk between the auxin and GA signaling pathways in poplar stems during cambial development. Biochemical analysis revealed that ARF7 physically interacts with RGL1 and IAA9 through distinct domains. The arf7 loss-of-function mutant showed markedly attenuated responses to auxin and GA, whereas transgenic poplar plants overexpressing ARF7 displayed strongly improved cambial activity. ARF7 directly binds to the promoter region of the cambial stem cell regulator WOX4 to modulate its expression, thus integrating auxin and GA signaling to regulate cambial activity. Furthermore, the direct activation of PIN-FORMED 1 expression by ARF7 in the RGL1-ARF7-IAA9 module increased GA-dependent cambial activity via polar auxin transport. Collectively, these findings reveal that the crosstalk between auxin and GA signaling mediated by the RGL1-ARF7-IAA9 module is crucial for the precise regulation of cambial development in poplar.

FBP1 inhibits NSCLC stemness by promoting ubiquitination of Notch1 intracellular domain and accelerating degradation.

The existence of cancer stem cells is widely acknowledged as the underlying cause for the challenging curability and high relapse rates observed in various tumor types, including non-small cell lung cancer (NSCLC). Despite extensive research on numerous therapeutic targets for NSCLC treatment, the strategies to effectively combat NSCLC stemness and achieve a definitive cure are still not well defined. The primary objective of this study was to examine the underlying mechanism through which Fructose-1,6-bisphosphatase 1 (FBP1), a gluconeogenic enzyme, functions as a tumor suppressor to regulate the stemness of NSCLC. Herein, we showed that overexpression of FBP1 led to a decrease in the proportion of CD133-positive cells, weakened tumorigenicity, and decreased expression of stemness factors. FBP1 inhibited the activation of Notch signaling, while it had no impact on the transcription level of Notch 1 intracellular domain (NICD1). Instead, FBP1 interacted with NICD1 and the E3 ubiquitin ligase FBXW7 to facilitate the degradation of NICD1 through the ubiquitin-proteasome pathway, which is independent of the metabolic enzymatic activity of FBP1. The aforementioned studies suggest that targeting the FBP1-FBXW7-NICD1 axis holds promise as a therapeutic approach for addressing the challenges of NSCLC recurrence and drug resistance.

Upregulation of CoQ shifts ferroptosis dependence from GPX4 to FSP1 in acquired radioresistance.

Acquired radioresistance is the primary contributor to treatment failure of radiotherapy, with ferroptosis is identified as a significant mechanism underlying cell death during radiotherapy. Although resistance to ferroptosis has been observed in both clinical samples of radioresistant cells and cell models, its mechanism remains unidentified. Herein, our investigation revealed that radioresistant cells exhibited greater tolerance to Glutathione Peroxidase 4 (GPX4) inhibitors and, conversely, increased sensitivity to ferroptosis suppressor protein 1 (FSP1) inhibitors compared to their sensitive counterparts. This observation suggested that FSP1 might play a dominant role in the development of radioresistance. Notably, the knockout of FSP1 demonstrated considerably superior efficacy in resensitizing cells to radiotherapy compared to the knockout of GPX4. To elucidate the driving force behind this functional shift, we conducted a metabolomic assay, which revealed an upregulation of Coenzyme Q (CoQ) synthesis and a downregulation of glutathione synthesis in the acquired radioresistance cells. Mechanistically, CoQ synthesis was found to be supported by aarF domain containing kinase 3-mediated phosphorylation of CoQ synthases, while the downregulation of Solute carrier family 7 member 11 led to decreased glutathione synthesis. Remarkably, our retrospective analysis of clinical response data further validated that the additional administration of statin during radiotherapy, which could impede CoQ production, effectively resensitized radioresistant cells to radiation. In summary, our findings demonstrate a dependency shift from GPX4 to FSP1 driven by altered metabolite synthesis during the acquisition of radioresistance. Moreover, we provide a promising therapeutic strategy for reversing radioresistance by inhibiting the FSP1-CoQ pathway.

Atomic-scale probing of heterointerface phonon bridges in nitride semiconductor.

Interface phonon modes that are generated by several atomic layers at the heterointerface play a major role in the interface thermal conductance for nanoscale high-power devices such as nitride-based high-electron-mobility transistors and light-emitting diodes. Here we measure the local phonon spectra across AlN/Si and AlN/Al interfaces using atomically resolved vibrational electron energy-loss spectroscopy in a scanning transmission electron microscope. At the AlN/Si interface, we observe various interface phonon modes, of which the extended and localized modes act as bridges to connect the bulk AlN modes and bulk Si modes and are expected to boost the phonon transport, thus substantially contributing to interface thermal conductance. In comparison, no such phonon bridge is observed at the AlN/Al interface, for which partially extended modes dominate the interface thermal conductivity. This work provides valuable insights into understanding the interfacial thermal transport in nitride semiconductors and useful guidance for thermal management via interface engineering.

Oncogenic Kras drives invasion and maintains metastases in colorectal cancer.

Human colorectal cancer (CRC) is a major cause of cancer mortality and frequently harbors activating mutations in the KRAS gene. To understand the role of oncogenic KRAS in CRC, we engineered a mouse model of metastatic CRC that harbors an inducible oncogenic Kras allele (Krasmut ) and conditional null alleles of Apc and Trp53 (iKAP). The iKAP model recapitulates tumor progression from adenoma through metastases. Whole-exome sequencing revealed that the Krasmut allele was heterogenous in primary tumors yet homogenous in metastases, a pattern consistent with activated Krasmut signaling being a driver of progression to metastasis. System-level and functional analyses revealed the TGF-ß pathway as a key mediator of Krasmut -driven invasiveness. Genetic extinction of Krasmut resulted in specific elimination of the Krasmut subpopulation in primary and metastatic tumors, leading to apoptotic elimination of advanced invasive and metastatic disease. This faithful CRC model provides genetic evidence that Krasmut drives CRC invasion and maintenance of metastases.

Structural, Spectroscopic, and Computational Insights from Canavanine-Bound and Two Catalytically Compromised Variants of the Ethylene-Forming Enzyme.

The ethylene-forming enzyme (EFE) is an Fe(II), 2-oxoglutarate (2OG), and l-arginine (l-Arg)-dependent oxygenase that either forms ethylene and three CO2/bicarbonate from 2OG or couples the decarboxylation of 2OG to C5 hydroxylation of l-Arg. l-Arg binds with C5 toward the metal center, causing 2OG to change from monodentate to chelate metal interaction and OD1 to OD2 switch of D191 metal coordination. We applied anaerobic UV-visible spectroscopy, X-ray crystallography, and computational approaches to three EFE systems with high-resolution structures. The ineffective l-Arg analogue l-canavanine binds to the EFE with O5 pointing away from the metal center while promoting chelate formation by 2OG but fails to switch the D191 metal coordination from OD1 to OD2. Substituting alanine for R171 that interacts with 2OG and l-Arg inactivates the protein, prevents metal chelation by 2OG, and weakens l-Arg binding. The R171A EFE had electron density at the 2OG binding site that was identified by mass spectrometry as benzoic acid. The substitution by alanine of Y306 in the EFE, a residue 12 Å away from the catalytic metal center, generates an interior cavity that leads to multiple local and distal structural changes that reduce l-Arg binding and significantly reduce the enzyme activity. Flexibility analyses revealed correlated and anticorrelated motions in each system, with important distinctions from the wild-type enzyme. In combination, the results are congruent with the currently proposed enzyme mechanism, reinforce the importance of metal coordination by OD2 of D191, and highlight the importance of the second coordination sphere and longer range interactions in promoting EFE activity.

Subcellular localization requirements and specificities for plant immune receptor Toll-interleukin-1 receptor signaling.

Recent work shed light on how plant intracellular immune receptors of the nucleotide-binding leucine-rich repeat (NLR) family are activated upon pathogen effector recognition to trigger immune responses. Activation of Toll-interleukin-1 receptor (TIR) domain-containing NLRs (TNLs) induces receptor oligomerization and close proximity of the TIR domain, which is required for TIR enzymatic activity. TIR-catalyzed small signaling molecules bind to EDS1 family heterodimers and subsequently activate downstream helper NLRs, which function as Ca2+ permeable channel to activate immune responses eventually leading to cell death. Subcellular localization requirements of TNLs and signaling partners are not well understood, although they are required to understand fully the mechanisms underlying NLR early signaling. TNLs show diverse subcellular localization while EDS1 shows nucleocytosolic localization. Here, we studied the impact of TIR and EDS1 mislocalization on the signaling activation of different TNLs. In Nicotiana benthamiana, our results suggest that close proximity of TIR domains isolated from flax L6 and Arabidopsis RPS4 and SNC1 TNLs drives signaling activation from different cell compartments. Nevertheless, both Golgi-membrane anchored L6 and nucleocytosolic RPS4 have the same requirements for EDS1 subcellular localization in Arabidopsis thaliana. By using mislocalized variants of EDS1, we found that autoimmune L6 and RPS4 TIR domain can induce seedling cell death when EDS1 is present in the cytosol. However, when EDS1 is restricted to the nucleus, both induce a stunting phenotype but no cell death. Our data point out the importance of thoroughly investigating the dynamics of TNLs and signaling partners subcellular localization to understand TNL signaling fully.

Cis-eQTLs in seven duck tissues identify novel candidate genes for growth and carcass traits.

BACKGROUND: Expression quantitative trait loci (eQTL) studies aim to understand the influence of genetic variants on gene expression. The colocalization of eQTL mapping and GWAS strategy could help identify essential candidate genes and causal DNA variants vital to complex traits in human and many farm animals. However, eQTL mapping has not been conducted in ducks. It is desirable to know whether eQTLs within GWAS signals contributed to duck economic traits. RESULTS: In this study, we conducted an eQTL analysis using publicly available RNA sequencing data from 820 samples, focusing on liver, muscle, blood, adipose, ovary, spleen, and lung tissues. We identified 113,374 cis-eQTLs for 12,266 genes, a substantial fraction 39.1% of which were discovered in at least two tissues. The cis-eQTLs of blood were less conserved across tissues, while cis-eQTLs from any tissue exhibit a strong sharing pattern to liver tissue. Colocalization between cis-eQTLs and genome-wide association studies (GWAS) of 50 traits uncovered new associations between gene expression and potential loci influencing growth and carcass traits. SRSF4, GSS, and IGF2BP1 in liver, NDUFC2 in muscle, ELF3 in adipose, and RUNDC1 in blood could serve as the candidate genes for duck growth and carcass traits. CONCLUSIONS: Our findings highlight substantial differences in genetic regulation of gene expression across duck primary tissues, shedding light on potential mechanisms through which candidate genes may impact growth and carcass traits. Furthermore, this availability of eQTL data offers a valuable resource for deciphering further genetic association signals that may arise from ongoing extensive endeavors aimed at enhancing duck production traits.

Unlocking Direct Lithium Extraction in Harsh Conditions through Thiol-Functionalized Metal-Organic Framework Subnanofluidic Membranes.

Metal-organic framework (MOF) membranes with high ion selectivity are highly desirable for direct lithium-ion (Li+) separation from industrial brines. However, very few MOF membranes can efficiently separate Li+ from brines of high Mg2+/Li+ concentration ratios and keep stable in ultrahigh Mg2+-concentrated brines. This work reports a type of MOF-channel membranes (MOFCMs) by growing UiO-66-(SH)2 into the nanochannels of polymer substrates to improve the efficiency of MOF membranes for challenging Li+ extraction. The resulting membranes demonstrate excellent monovalent metal ion selectivity over divalent metal ions, with Li+/Mg2+ selectivity up to 103 since Mg2+ should overcome a higher energy barrier than Li+ when transported through the MOF pores, as confirmed by molecular dynamics simulations. Under dual-ion diffusion, as the Mg2+/Li+ mole ratio of the feed solution increases from 0.2 to 30, the membrane Li+/Mg2+ selectivity decreases from 1516 to 19, corresponding to the purity of lithium products between 99.9 and 95.0%. Further research on multi-ion diffusion that involves Mg2+ and three monovalent metal ions (K+, Na+, and Li+, referred to as M+) in the feed solutions shows a significant improvement in Li+/Mg2+ separation efficiency. The Li+/Mg2+ selectivity can go up to 1114 when the Mg2+/M+ molar concentration ratio is 1:1, and it remains at 19 when the ratio is 30:1. The membrane selectivity is also stable for 30 days in a highly concentrated solution with a high Mg2+/Li+ concentration ratio. These results indicate the feasibility of the MOFCMs for direct lithium extraction from brines with Mg2+ concentrations up to 3.5 M. This study provides an alternative strategy for designing efficient MOF membranes in extracting valuable minerals in the future.

From Bulk to Interface: Solvent Exchange Dynamics and Their Role in Ion Transport and the Interfacial Model of Rechargeable Magnesium Batteries.

Multivalent battery chemistries have been explored in response to the increasing demand for high-energy rechargeable batteries utilizing sustainable resources. Solvation structures of working cations have been recognized as a key component in the design of electrolytes; however, most structure-property correlations of metal ions in organic electrolytes usually build upon favorable static solvation structures, often overlooking solvent exchange dynamics. We here report the ion solvation structures and solvent exchange rates of magnesium electrolytes in various solvents by using multimodal nuclear magnetic resonance (NMR) analysis and molecular dynamics/density functional theory (MD/DFT) calculations. These magnesium solvation structures and solvent exchange dynamics are correlated to the combined effects of several physicochemical properties of the solvents. Moreover, Mg2+ transport and interfacial charge transfer efficiency are found to be closely correlated to the solvent exchange rate in the binary electrolytes where the solvent exchange is tunable by the fraction of diluent solvents. Our primary findings are (1) most battery-related solvents undergo ultraslow solvent exchange coordinating to Mg2+ (with time scales ranging from 0.5 µs to 5 ms), (2) the cation transport mechanism is a mixture of vehicular and structural diffusion even at the ultraslow exchange limit (with faster solvent exchange leading to faster cation transport), and (3) an interfacial model wherein organic-rich regions facilitate desolvation and inorganic regions promote Mg2+ transport is consistent with our NMR, electrochemistry, and cryogenic X-ray photoelectron spectroscopy (cryo-XPS) results. This observed ultraslow solvent exchange and its importance for ion transport and interfacial properties necessitate the judicious selection of solvents and informed design of electrolyte blends for multivalent electrolytes.

Nab-paclitaxel plus S-1 versus nab-paclitaxel plus gemcitabine in patients with advanced pancreatic cancer: a multicenter, randomized, phase II study.

BACKGROUND: Encouraging antitumor activity of nab-paclitaxel plus S-1 (AS) has been shown in several small-scale studies. This study compared the efficacy and safety of AS versus standard-of-care nab-paclitaxel plus gemcitabine (AG) as a first-line treatment for advanced pancreatic cancer (PC). METHODS: In this multicenter, randomized, phase II trial, eligible patients with unresectable, locally advanced, or metastatic PC were recruited and randomly assigned (1:1) to receive AS (nab-paclitaxel 125 mg/m2 on days 1 and 8; S-1 twice daily on days 1 through 14) or AG (nab-paclitaxel 125 mg/m2 on days 1 and 8; gemcitabine 1000 mg/m2 on days 1 and 8) for 6 cycles. The primary endpoint was progression-free survival (PFS). RESULTS: Between July 16, 2019, and September 9, 2022, 62 patients (AS, n = 32; AG, n = 30) were treated and evaluated. With a median follow-up of 8.36 months at preplanned interim analysis (data cutoff, March 24, 2023), the median PFS (8.48 vs 4.47 months; hazard ratio [HR], 0.402; P = .002) and overall survival (OS; 13.73 vs 9.59 months; HR, 0.226; P < .001) in the AS group were significantly longer compared to the AG group. More patients had objective response in the AS group than AG group (37.50% vs 6.67%; P = .005). The most common grade 3-4 adverse events were neutropenia and leucopenia in both groups, and gamma glutamyl transferase increase was observed only in the AG group. CONCLUSION: The first-line AS regimen significantly extended both PFS and OS of Chinese patients with advanced PC when compared with the AG regimen, with a comparable safety profile. (ClinicalTrials.gov Identifier: NCT03636308).

Co-targeting ASK1 and THRß synergistically improves steatohepatitis and fibrosis in a MASH animal model.

PURPOSE: Metabolic dysfunction-associated steatohepatitis (MASH) is a liver disease that has gained widespread attention globally. Unfortunately, there is no approved treatment for this condition yet. However, recent research has identified Apoptosis signal-regulating kinase 1 (ASK1) and thyroid hormone receptor-ß (THR-ß) as potential targets for treating MASH. Although the individual effects of these two targets have been studied, their combinatory effect has not been well defined. Therefore, further research is needed to investigate the potential benefits of targeting both ASK1 and THR-ß for treating MASH. METHODS: We established a MASH model using the HFHFrC diet (high fat, high fructose, and cholesterol) and carbon tetrachloride (CCL4). Forty mice were evenly assigned to four groups: vehicle, GS4997 (an ASK1 inhibitor), MGL3196 (a THRß agonist), GS4997+ MGL3196 combination (combo). The drugs were administered for 8 weeks, after which the mice were sacrificed for serum biochemical tests, liver TG and TC evaluation, liver histopathological study, and gene expression validation. RESULTS: GS4997 and MGL3196, when used in combination, have been shown to have synergistic effects on various parameters. Firstly, they synergistically reduced body weight and liver body weight ratio. Secondly, this combination also synergistically lowered AST and TC. Thirdly, synergistic effects were also observed in liver TG and TC reduction. Fourthly, we further confirmed that GS4997 mildly improved liver inflammation, ballooning, and fibrosis, but exhibited incredible histopathological efficacy when combined with MGL3196. Finally, this combinatory effect can be interpreted by synergistically regulating lipid-related genes such as Dio1, Ctp1-α, and Cat, inflammation-related genes such as Il-6, Il-8, and Mcp-1, and fibrosis-related genes such as Tgf-ß, Col1α1, and Col6α3. CONCLUSION: GS4997 and MGL3196, when used in combination, have been shown to have a comprehensive effect on MASH by synergistically regulating lipid, inflammation, and fibrosis-related gene expression through co-targeting ASK1 and THRß.