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Programmable RNA editing enables reversible recoding of RNA information for research and disease treatment. Previously, we developed a programmable adenosine-to-inosine (A-to-I) RNA editing approach by fusing catalytically inactivate RNA-targeting CRISPR-Cas13 (dCas13) with the adenine deaminase domain of ADAR2. Here, we report a cytidine-to-uridine (C-to-U) RNA editor, referred to as RNA Editing for Specific C-to-U Exchange (RESCUE), by directly evolving ADAR2 into a cytidine deaminase. RESCUE doubles the number of mutations targetable by RNA editing and enables modulation of phosphosignaling-relevant residues. We apply RESCUE to drive β-catenin activation and cellular growth. Furthermore, RESCUE retains A-to-I editing activity, enabling multiplexed C-to-U and A-to-I editing through the use of tailored guide RNAs.

Metastasis accounts for 90% of cancer-related deaths among the patients. The transformation of epithelial cells into mesenchymal cells with molecular alterations can occur during epithelial–mesenchymal transition (EMT). The EMT mechanism accelerates the cancer metastasis and drug resistance ability in human cancers. Among the different regulators of EMT, Wnt/β-catenin axis has been emerged as a versatile modulator. Wnt is in active form in physiological condition due to the function of GSK-3β that destructs β-catenin, while ligand–receptor interaction impairs GSK-3β function to increase β-catenin stability and promote its nuclear transfer. Regarding the oncogenic function of Wnt/β-catenin, its upregulation occurs in human cancers and it can accelerate EMT-mediated metastasis and drug resistance. The stimulation of Wnt by binding Wnt ligands into Frizzled receptors can enhance β-catenin accumulation in cytoplasm that stimulates EMT and related genes upon nuclear translocation. Wnt/β-catenin/EMT axis has been implicated in augmenting metastasis of both solid and hematological tumors. The Wnt/EMT-mediated cancer metastasis promotes the malignant behavior of tumor cells, causing therapy resistance. The Wnt/β-catenin/EMT axis can be modulated by upstream mediators in which non-coding RNAs are main regulators. Moreover, pharmacological intervention, mainly using phytochemicals, suppresses Wnt/EMT axis in metastasis suppression. Graphical abstract

Mammalian sex determination is controlled by the antagonistic interactions of two genetic pathways: The SRY-SOX9-FGF9 network promotes testis determination partly by opposing proovarian pathways, while RSPO1/WNT-β-catenin/FOXL2 signals control ovary development by inhibiting SRY-SOX9-FGF9. The molecular basis of this mutual antagonism is unclear. Here we show that ZNRF3, a WNT signaling antagonist and direct target of RSPO1-mediated inhibition, is required for sex determination in mice. XY mice lacking ZNRF3 exhibit complete or partial gonadal sex reversal, or related defects. These abnormalities are associated with ectopic WNT/β-catenin activity and reduced Sox9 expression during fetal sex determination. Using exome sequencing of individuals with 46, XY disorders of sex development, we identified three human ZNRF3 variants in very rare cases of XY female presentation. We tested two missense variants and show that these disrupt ZNRF3 activity in both human cell lines and zebrafish embryo assays. Our data identify a testis-determining function for ZNRF3 and indicate a mechanism of direct molecular interaction between two mutually antagonistic organogenetic pathways.

Background This study aimed to investigate whether probiotics can ameliorate the H. pylori -induced Wnt/β-catenin-related COX-2 carcinogenesis signaling pathway by regulating the expression of microRNAs (miRNAs). Methods An H. pylori isolate and GES-1 cells were used to establish a COX-2-associated carcinogenesis axis. Western blot analysis was conducted to investigate Wnt/β-catenin and COX-2 signaling. Next-generation sequencing and DIANA Tools identified significant differences in miRNA expressions. The probiotics Lactobacillus acidophilus and Bifidobacterium lactis were used to study anti-carcinogenesis effects in GES-1 and miRNA-transfected GES-1 cells. The H. pylori -infected patients with intestinal metaplasia (IM) were randomly allocated into probiotic treatment or not after successful eradication, the IM regression was assessed by the 2nd esophagogastroduodenoscopy one year after treatment. Results Pretreatment with probiotics significantly reduced H. pylori -induced nuclear β-catenin phosphorylation and COX-2 levels in GES-1 cells. Among 9 significantly altered miRNAs, miR-185 was the only miRNA targeting the Wnt/β-catenin signaling pathway. H. pylori increased miR-185 expression and upregulated COX-2 carcinogenesis through the Wnt/β-catenin pathway, but not the JAK2/STAT3 pathway. B. lactis ameliorated H. pylori -induced miR-185 expression and nuclear β-catenin/COX-2 signaling in a dose-dependent manner. In the 6-month probiotic-treated patients had a significantly higher IM regression rate than controls (intention-to-treat: 37.5 vs 11.5%, OR: 4.60, 95% CI: 1.134–18.65, p  = 0.025; per-protocol: 46.2 vs 17.6%, OR: 4.00, 95% CI: 0.923–17.33, p  = 0.055). Patients without IM regression had significantly higher miR-185 levels in follow-up biopsies ( p  < 0.01). Conclusions Pretreatment with B. lactis ameliorated the H. pylori -induced COX-2 carcinogenesis pathway by reducing miR-185 expression, which targets Wnt/β-catenin signaling. (ClinicalTrials.gov, NCT05544396).

Deregulated Wnt/β-catenin signaling is one of the main genetic alterations in human hepatocellular carcinoma (HCC). Comprehensive genomic analyses have revealed that gain-of-function mutation of CTNNB1, which encodes β-catenin, and loss-of-function mutation of AXIN1 occur in approximately 35% of human HCC samples. Human HCCs with activation of the Wnt/β-catenin pathway demonstrate unique gene expression patterns and pathological features. Activated Wnt/β-catenin synergizes with multiple signaling cascades to drive HCC formation, and it functions through its downstream effectors. Therefore, strategies targeting Wnt/β-catenin have been pursued as possible therapeutics against HCC. Here, we review the genetic alterations and oncogenic roles of aberrant Wnt/β-catenin signaling during hepatocarcinogenesis. In addition, we discuss the implication of this pathway in HCC diagnosis, classification, and personalized treatment.

Nano- and microplastic particles (NMP) are strong environmental contaminants affecting marine ecosystems and human health. The negligible use of biodegradable plastics and the lack of knowledge about plastic uptake, accumulation, and functional consequences led us to investigate the short- and long-term effects in freshly isolated skin cells from mice. Using fluorescent NMP of several sizes (200 nm to 6 µm), efficient cellular uptake was observed, causing, however, only minor acute toxicity as metabolic activity and apoptosis data suggested, albeit changes in intracellular reactive species and thiol levels were observed. The internalized NMP induced an altered expression of various targets of the nuclear factor-2-related transcription factor 2 pathway and were accompanied by changed antioxidant and oxidative stress signaling responses, as suggested by altered heme oxygenase 1 and glutathione peroxide 2 levels. A highly increased beta-catenin expression under acute but not chronic NMP exposure was concomitant with a strong translocation from membrane to the nucleus and subsequent transcription activation of Wnt signaling target genes after both single-dose and chronic long-term NMP exposure. Moreover, fibroblast-to-myofibroblast transdifferentiation accompanied by an increase of α smooth muscle actin and collagen expression was observed. Together with several NMP-induced changes in junctional and adherence protein expression, our study for the first time elucidates the acute and chronic effects of NMP of different sizes in primary skin cells' signaling and functional biology, contributing to a better understanding of nano- and microplastic to health risks in higher vertebrates.

Metastasis associated lung adenocarcinoma transcript 1(MALAT1) is a long non‐coding RNA, broadly expressed in mammalian tissues including kidney and up‐regulated in a variety of cancer cells. To date, its functions in podocytes are largely unknown. β‐catenin is a key mediator in the canonical and non‐canonical Wnt signalling pathway; its aberrant expression promotes podocyte malfunction and albuminuria, and contributes to kidney fibrosis. In this study, we found that MALAT1 levels were increased in kidney cortices from C57BL/6 mice with streptozocin (STZ)‐induced diabetic nephropathy, and dynamically regulated in cultured mouse podocytes stimulated with high glucose, which showed a trend from rise to decline. The decline of MALAT1 levels was accompanied with β‐catenin translocation to the nuclei and enhanced expression of serine/arginine splicing factor 1 (SRSF1), a MALAT1 RNA‐binding protein. Further we showed early interference with MALAT1 siRNA partially restored podocytes function and prohibited β‐catenin nuclear accumulation and SRSF1 overexpression. Intriguingly, we showed that β‐catenin was involved in MALAT1 transcription by binding to the promotor region of MALAT1; β‐catenin knock‐down also decreased MALAT1 levels, suggesting a novel feedback regulation between MALAT1 and β‐catenin. Notably, β‐catenin deletion had limited effects on SRSF1 expression, demonstrating β‐catenin might serve as a downstream signal of SRSF1. These findings provided evidence for a pivotal role of MALAT1 in diabetic nephropathy and high glucose‐induced podocyte damage.

Many cancers have an unusual dependence on glutamine. However, most previous studies have focused on the contribution of glutamine to metabolic building blocks and the energy supply. Here, we report that cancer cells with aberrant expression of glutamate decarboxylase 1 (GAD1) rewire glutamine metabolism for the synthesis of γ-aminobutyric acid (GABA)—a prominent neurotransmitter—in non-nervous tissues. An analysis of clinical samples reveals that increased GABA levels predict poor prognosis. Mechanistically, we identify a cancer-intrinsic pathway through which GABA activates the GABA B receptor to inhibit GSK-3β activity, leading to enhanced β-catenin signalling. This GABA-mediated β-catenin activation both stimulates tumour cell proliferation and suppresses CD8 + T cell intratumoural infiltration, such that targeting GAD1 or GABA B R in mouse models overcomes resistance to anti-PD-1 immune checkpoint blockade therapy. Our findings uncover a signalling role for tumour-derived GABA beyond its classic function as a neurotransmitter that can be targeted pharmacologically to reverse immunosuppression. Huang et al. report upregulation of GABA synthesis and activation of β-catenin after rewiring of glutamine metabolism, which suppresses T-cell infiltration, enhances tumour growth and can be targeted to overcome resistance to immune checkpoint blockade.

Although the capacity for tissue regeneration of planarians is exceptional, planarians with more limited regenerative capacities are known; here knocking down components of the Wnt signalling pathway rescues head regeneration in the regeneration-impaired planarian Dendrocoelum lacteum , revealing that manipulating a single signalling pathway can reverse the evolutionary loss of regenerative potential. Controlling planarian regeneration capacity Planarians are flatworms common in streams and ponds whose capacity for tissue regeneration is legendary. But with more limited regenerative capacities are known. Three papers published in Nature this week study Planaria with differing regenerative capacities and identify the Wnt/β-catenin molecular signalling pathway, important in embryonic development and adult homeostasis in multicellular organisms, as central to the regeneration mechanism. Yoshihiko Umesono et al . identify ERK and β-catenin signalling as the basis for a morphogenetic gradient along the anterior–posterior axis that is required for regeneration. These authors also demonstrate that inhibition of β-catenin can rescue head regeneration in Phagocata kawakatsui , a planarian that otherwise cannot regenerate heads from the posterior pieces. James Sikes and Phillip Newmark show in Procotyla fluviatilis , which has restricted ability to replace missing tissues, that Wnt signalling is aberrantly regulated in regeneration-deficient tissues. Downregulation of Wnt signalling in these regions restores regenerative abilities, including the formation of blastemas and even new heads. Jochen Rink and colleagues show that in the otherwise regeneration-incompetent Dendrocoelum lacteum , knockdown of components in the Wnt signalling pathway introduces the ability to regenerate lost tissues. Species capable of regenerating lost body parts occur throughout the animal kingdom, yet close relatives are often regeneration incompetent 1 , 2 . Why in the face of ‘survival of the fittest’ some animals regenerate but others do not remains a fascinating question 3 . Planarian flatworms are well known and studied for their ability to regenerate from minute tissue pieces, yet species with limited regeneration abilities have been described even amongst planarians 4 . Here we report the characterization of the regeneration defect in the planarian Dendrocoelum lacteum and its successful rescue. Tissue fragments cut from the posterior half of the body of this species are unable to regenerate a head and ultimately die 5 . We find that this defect originates during the early stages of head specification, which require inhibition of canonical Wnt signalling in other planarian species 6 , 7 , 8 . Notably, RNA interference (RNAi)-mediated knockdown of Dlac-β-catenin-1 , the Wnt signal transducer, restored the regeneration of fully functional heads on tail pieces, rescuing D. lacteum ’s regeneration defect. Our results demonstrate the utility of comparative studies towards the reactivation of regenerative abilities in regeneration-deficient animals. Furthermore, the availability of D. lacteum as a regeneration-impaired planarian model species provides a first step towards elucidating the evolutionary mechanisms that ultimately determine why some animals regenerate and others do not.

Renal fibrosis is the common pathological feature in a variety of chronic kidney diseases. Aging is highly associated with the progression of renal fibrosis. Among several determinants, mitochondrial dysfunction plays an important role in aging. However, the underlying mechanisms of mitochondrial dysfunction in age‐related renal fibrosis are not elucidated. Herein, we found that Wnt/β‐catenin signaling and renin–angiotensin system (RAS) activity were upregulated in aging kidneys. Concomitantly, mitochondrial mass and functions were impaired with aging. Ectopic expression of Klotho, an antagonist of endogenous Wnt/β‐catenin activity, abolished renal fibrosis in d‐galactose (d‐gal)‐induced accelerated aging mouse model and significantly protected renal mitochondrial functions by preserving mass and diminishing the production of reactive oxygen species. In an established aging mouse model, dickkopf 1, a more specific Wnt inhibitor, and the mitochondria‐targeted antioxidant mitoquinone restored mitochondrial mass and attenuated tubular senescence and renal fibrosis. In a human proximal tubular cell line (HKC‐8), ectopic expression of Wnt1 decreased biogenesis and induced dysfunction of mitochondria, and triggered cellular senescence. Moreover, d‐gal triggered the transduction of Wnt/β‐catenin signaling, which further activated angiotensin type 1 receptor (AT1), and then decreased the mitochondrial mass and increased cellular senescence in HKC‐8 cells and primary cultured renal tubular cells. These effects were inhibited by AT1 blocker of losartan. These results suggest inhibition of Wnt/β‐catenin signaling and the RAS could slow the onset of age‐related mitochondrial dysfunction and renal fibrosis. Taken together, our results indicate that Wnt/β‐catenin/RAS signaling mediates age‐related renal fibrosis and is associated with mitochondrial dysfunction. Wnt/β‐catenin signaling induces RAS activation, which promotes cellular senescence and age‐related kidney fibrosis in association with mitochondrial dysfunction that stems from a loss of mitochondrial biogenesis.