Optimized rAAV8 targeting acinar KLF4 ameliorates fibrosis in chronic pancreatitis via exosomes-enriched let-7s suppressing pancreatic stellate cells activation.

Chronic pancreatitis (CP) is marked by progressive fibrosis and the activation of pancreatic stellate cells (PSCs), accompanied by the destruction of pancreatic parenchyma, leading to the loss of acinar cells (ACs). Few research studies have explored the mechanism by which damaged ACs (DACs) contribute to PSCs activation and pancreatic fibrosis. Currently, there are no effective drugs for curing CP or limiting the progression of pancreatic fibrosis. In this research, co-culture with intact acinar cells (IACs) suppressed PSC activation, while co-culture with DACs did the opposite. Krüppel-like factor 4 (KLF4) was significantly upregulated in DACs and was established as the key molecule that switches ACs from PSCs-suppressor to PSCs-activator. We revealed the exosomes of IACs contributed to the anti-activated function of IACs-CS on PSCs. MiRNome profiling showed that let-7 family is significantly enriched in IAC-derived exosomes (>30% miRNome), which partially mediates IACs' suppressive impacts on PSCs. Furthermore, it has been observed that the enrichment of let-7 in exosomes was influenced by the expression level of KLF4. Mechanistic studies demonstrated that KLF4 in ACs upregulated Lin28A, thereby decreasing let-7 levels in AC-derived exosomes, and thus promoting PSCs activation. We utilized an adeno-associated virus specifically targeting KLF4 in ACs (shKLF4-pAAV) to suppress PSCs activation in CP, resulting in reduced pancreatic fibrosis. IAC-derived exosomes hold potential as potent weapons against PSCs activation via let-7s, while activated KLF4/Lin28A signaling in DACs diminished such functions. ShKLF4-pAAV holds promise as a novel therapeutic approach for CP.

Tumor suppressor let-7 acts as a key regulator for pluripotency gene expression in Muse cells.

In embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), the expression of an RNA-binding pluripotency-relevant protein, LIN28, and the absence of its antagonist, the tumor-suppressor microRNA (miRNA) let-7, play a key role in maintaining pluripotency. Muse cells are non-tumorigenic pluripotent-like stem cells residing in the bone marrow, peripheral blood, and organ connective tissues as pluripotent surface marker SSEA-3(+). They express pluripotency genes, differentiate into triploblastic-lineage cells, and self-renew at the single cell level. Muse cells do not express LIN28 but do express let-7 at higher levels than in iPSCs. In Muse cells, we demonstrated that let-7 inhibited the PI3K-AKT pathway, leading to sustainable expression of the key pluripotency regulator KLF4 as well as its downstream genes, POU5F1, SOX2, and NANOG. Let-7 also suppressed proliferation and glycolysis by inhibiting the PI3K-AKT pathway, suggesting its involvement in non-tumorigenicity. Furthermore, the MEK/ERK pathway is not controlled by let-7 and may have a pivotal role in maintaining self-renewal and suppression of senescence. The system found in Muse cells, in which the tumor suppressor let-7, but not LIN28, tunes the expression of pluripotency genes, might be a rational cell system conferring both pluripotency-like properties and a low risk for tumorigenicity.

Exosomes derived from cancer-associated fibroblasts promote tumorigenesis, metastasis and chemoresistance of colorectal cancer by upregulating circ_0067557 to target Lin28.

BACKGROUND: Cancer associated fibroblasts (CAFs) can remodel tumor microenvironment by secreting exosomes. This study aimed to investigate the role of exosomes derived from cancer-associated fibroblasts in colorectal cancer (CRC) progression. METHODS: Circular RNA (circRNA) array was used to identify differentially expressed circRNAs in exosomes from normal fibroblasts (NFs) and CAFs, and confirmed one differentially expressed circRNA circ_0067557 by real-time PCR. The effect of circ_0067557 on proliferation, metastasis, chemoresistance and apoptosis was verified by wound heal, tranwell, CCK8, sphere-forming and flow cytometry assay. RESULTS: Circ_0067557 expression in exosomes from CAFs was higher than those from NFs. CAF-derived exosomes promoted the proliferation, migration, invasion and chemoresistance of CRC cells while suppressed apoptosis. Silencing of circ_0067557 inhibited malignant phenotypes of CRC cells by targeting Lin28A and Lin28B. Moreover, CAF-derived exosomes enhanced the growth of CRC xenograft tumors. CONCLUSION: Circ_0067557/Lin28A and Lin28B signal axis may be a potential therapy target for CRC.

Effect and Mechanism of LIN28 on Ferroptosis in Mg2+-free Rat Hippocampal Neuron Model of Epilepsy.

Studies have demonstrated that LIN28 is expressed in the CNS and may exert protective effects on neurons. However, it remains unknown whether LIN28 regulates ferroptosis in the context of epilepsy. In this study, we established an epilepsy model by culturing hippocampal neurons from rats in a magnesium-free (Mg2+-free) medium. In Mg2+-depleted conditions, hippocampal neurons exhibited reduced LIN28 expression, heightened miR-142-5p expression, decreased glutathione peroxidase (GPX) activity and expression, elevated levels of reactive oxygen species (ROS) and malondialdehyde (MDA), resulting in a significant decline in cell viability and an increase in ferroptosis. Conversely, overexpression of LIN28 reversed these trends in the mentioned indices. Altogether, this study reveals that LIN28 may exert neuroprotective effects by inhibiting the miR-142-5p expression and suppressing ferroptosis in hippocampal neurons induced by Mg2+-free via increasing GPX4 expression.

Regulating Protein-RNA Interactions: Advances in Targeting the LIN28/Let-7 Pathway.

Originally discovered in C. elegans, LIN28 is an evolutionarily conserved zinc finger RNA-binding protein (RBP) that post-transcriptionally regulates genes involved in developmental timing, stem cell programming, and oncogenesis. LIN28 acts via two distinct mechanisms. It blocks the biogenesis of the lethal-7 (let-7) microRNA (miRNA) family, and also directly binds messenger RNA (mRNA) targets, such as IGF-2 mRNA, and alters downstream splicing and translation events. This review focuses on the molecular mechanism of LIN28 repression of let-7 and current strategies to overcome this blockade for the purpose of cancer therapy. We highlight the value of the LIN28/let-7 pathway as a drug target, as multiple oncogenic proteins that the pathway regulates are considered undruggable due to their inaccessible cellular location and lack of cavities for small molecule binding.

A Multi-Omics Approach Reveals Enrichment in Metabolites Involved in the Regulation of the Glutathione Pathway in LIN28B-Dependent Cancer Cells.

The RNA-binding protein LIN28B, identified as an independent risk factor in high-risk neuroblastoma patients, is implicated in adverse treatment outcomes linked to metastasis and chemoresistance. Despite its clinical significance, the impact of LIN28B on neuroblastoma cell metabolism remains unexplored. This study employs a multi-omics approach, integrating transcriptome and metabolome data, to elucidate the global metabolic program associated with varying LIN28B expression levels over time. Our findings reveal that escalating LIN28B expression induces a significant metabolic rewiring in neuroblastoma cells. Specifically, LIN28B prompts a time-dependent increase in the release rate of metabolites related to the glutathione and aminoacyl-tRNA biosynthetic pathways, concomitant with a reduction in glucose uptake. These results underscore the pivotal role of LIN28B in governing neuroblastoma cell metabolism and suggest a potential disruption in the redox balance of LIN28B-bearing cells. This study offers valuable insights into the molecular mechanisms underlying LIN28B-associated adverse outcomes in neuroblastoma, paving the way for targeted therapeutic interventions.

EGCG Disrupts the LIN28B/Let-7 Interaction and Reduces Neuroblastoma Aggressiveness.

Neuroblastoma (NB) is the most commonly diagnosed extracranial solid tumor in children, accounting for 15% of all childhood cancer deaths. Although the 5-year survival rate of patients with a high-risk disease has increased in recent decades, NB remains a challenge in pediatric oncology, and the identification of novel potential therapeutic targets and agents is an urgent clinical need. The RNA-binding protein LIN28B has been identified as an oncogene in NB and is associated with a poor prognosis. Given that LIN28B acts by negatively regulating the biogenesis of the tumor suppressor let-7 miRNAs, we reasoned that selective interference with the LIN28B/let-7 miRNA interaction would increase let-7 miRNA levels, ultimately leading to reduced NB aggressiveness. Here, we selected (-)-epigallocatechin 3-gallate (EGCG) out of 4959 molecules screened as the molecule with the best inhibitory activity on LIN28B/let-7 miRNA interaction and showed that treatment with PLC/PLGA-PEG nanoparticles containing EGCG (EGCG-NPs) led to an increase in mature let-7 miRNAs and a consequent inhibition of NB cell growth. In addition, EGCG-NP pretreatment reduced the tumorigenic potential of NB cells in vivo. These experiments suggest that the LIN28B/let-7 miRNA axis is a good therapeutic target in NB and that EGCG, which can interfere with this interaction, deserves further preclinical evaluation.

Expression of Pluripotency Factors OCT4 and LIN28 Correlates with Survival Outcome in Lung Adenocarcinoma.

Background and Objectives: Lung adenocarcinoma is a leading cause of cancer-related mortality despite recent therapeutic advances. Cancer stem cells have gained increasing attention due to their ability to induce cancer cell proliferation through self-renewal and differentiation into multiple cell lineages. OCT4 and LIN28 (and their homologs A and B) have been identified as key regulators of pluripotency in mammalian embryonic (ES) and induced stem (IS) cells, and they are the crucial regulators of cancer progression. However, their exact role in lung adenocarcinoma has not yet been clarified. Materials and Methods: The aim of this study was to explore the role of the pluripotency factors OCT4 and LIN28 in a cohort of surgically resected human lung adenocarcinomas to reveal possible biomarkers for lung adenocarcinoma prognosis and potential therapeutic targets. The expressions of OCT4, LIN28A and LIN28B were analyzed in formalin-fixed, paraffin-embedded tissue samples from 96 patients with lung adenocarcinoma by immunohistochemistry. The results were analyzed with clinicopathologic parameters and were related to the prognosis of patients. Results: Higher OCT4 expression was related to an improved 5-year overall survival (OS) rate (p < 0.001). Nuclear LIN28B expression was lower in stage I and II tumors (p < 0.05) compared to advanced stage tumors. LIN28B cytoplasmic expression was associated with 5-year OS rates not only in univariate (p < 0.005), but also in multivariate analysis (where age, gender, histopathological subtype and stage were used as cofactors, p < 0.01 HR = 2.592). Patients with lower LIN28B expression showed improved 5-year OS rates compared to patients with increased LIN28B expression. Conclusions: Our findings indicate that OCT4 and LIN28B are implicated in lung adenocarcinoma progression and prognosis outcome; thus, they serve as promising prognostic biomarkers and putative therapeutic targets in lung adenocarcinomas.

Progress on the role of LIN28A/B in tumor development and progression.

LIN28A and its homolog LIN28B are highly conserved RNA-binding proteins that play important roles in early embryonic development, somatic cell reprogramming, metabolism and tumorigenesis. LIN28A/B are highly expressed in a variety of malignant tumors such as breast cancer. They play important roles in the initiation, maintenance, and metastasis of tumors and are associated with poor prognosis. Previous studies have shown that the main regulatory mechanisms of LIN28A/B include let-7s dependent ways and let-7s independent ways, such as directly targeting mRNA. In this review, we summarize the function and molecular regulatory mechanisms of LIN28A/B in malignant tumors such as liver cancer, breast cancer and colorectal cancer, in order to provide references for further exploring the function and mechanism of LIN28A/B and their possible roles in clinical applications.

The role of Lin28A and Lin28B in cancer beyond Let-7.

Lin28A and Lin28B are paralogous RNA-binding proteins that play fundamental roles in development and cancer by regulating the microRNA family of tumor suppressor Let-7. Although Lin28A and Lin28B share some functional similarities with Let-7 inhibitors, they also have distinct expression patterns and biological functions. Increasing evidence indicates that Lin28A and Lin28B differentially impact cancer stem cell properties, epithelial-mesenchymal transition, metabolic reprogramming, and other hallmarks of cancer. Therefore, it is important to understand the overexpression of Lin28A and Lin28B paralogs in specific cancer contexts. In this review, we summarize the main similarities and differences between Lin28A and Lin28B, their implications in different cellular processes, and their role in different types of cancer. In addition, we provide evidence of other specific targets of each lin28 paralog, as well as the lncRNAs and miRNAs that promote or inhibit its expression, and how this impacts cancer development and progression.

Clinical significance of LIN28A gene polymorphisms and expression in pan-cancer: a meta-analysis and bioinformatic analysis.

Several studies have reported the relationship between LIN28A gene polymorphisms (rs3811463 T > C and rs34787247 G > A) and cancer susceptibility, but the results are inconsistent and need further clarification. The current study aimed to evaluate their relationship and also to explore the relationship between LIN28A gene expression and immune infiltration, tumor stage, survival prognosis, and drug sensitivity in pan-cancer. The meta-analysis and data mining were completed by STATA software and the GSCA platform, respectively. The meta-analysis showed that the rs3811463 polymorphism was not associated with cancer susceptibility, while the rs34787247 polymorphism was associated with cancer susceptibility in the Chinese population [AA vs. GG: Odd Ratio (OR)=1.98, 95% Confidence Interval (CI)=1.35-2.89, PZ<0.001; GA vs. GG: OR = 1.17, 95%CI= 1.01-1.36, PZ=0.04; (AA + GA) vs. GG: OR = 1.24, 95%CI = 1.07-1.43, PZ=0.004; AA vs. (GA + GG): OR = 1.90, 95%CI = 1.30- 2.78, PZ=0.001; A vs. G: OR = 1.27, 95%CI = 1.12-1.44, PZ<0.001]. LIN28A gene expression was associated not only with immune infiltration, pathological stage, and survival prognosis of certain cancers, but also with sensitivity to multiple anticancer drugs, such as cisplatin, pazopanib, olaparib, and selumetinib. In conclusion, the current study suggested that the rs34787247 G > A polymorphism might be used as a cancer risk marker in the Chinese population, and LIN28A might serve as a prognostic marker and therapeutic target for certain cancers.

Expression of IMP3 and LIN28A RNA-Binding Proteins in Placentas of Patients with Pre-Eclampsia with and without Severe Features.

BACKGROUND: this study aimed to determine the expression of RNA-binding oncofetal proteins IMP3 and LIN28A in extravillous (EVT) and villous trophoblast (VT) cells of placentas from pre-eclamptic (PE) pregnancies to better understand the pathogenesis of PE. METHODS: placental tissue of 10 patients with PE with severe features, 10 patients with PE without severe features and 20 age-matched healthy pregnancy controls were analyzed by immunohistochemistry, double immunofluorescence and qPCR. RESULTS: We found a decreased percentage of IMP3-positive EVT cells in PE with and without severe features compared to that of the healthy control (p < 0.001). IMP3 expression was significantly low in VT of PE placentas compared to that of the healthy control (p = 0.002). There was no significant difference in LIN28A expression between groups of PE and the control group. Additionally, we noticed the trend toward downregulation of IMP3 mRNA and LIN28A mRNA in severe PE compared to that of healthy controls. CONCLUSIONS: We demonstrated that IMP3 expression is decreased in EVT and VT cells of placentas from pregnancies complicated with both PE with and without severe features. However, additional functional investigations are needed to clarify the role of IMP3 as a potential therapeutic target in the management of PE.

Proto-oncogene c-Myb potentiates cisplatin resistance of ovarian cancer cells by downregulating lncRNA NKILA and modulating cancer stemness and LIN28A-let7 axis.

Ovarian cancer is a major gynecological cancer that has poor prognosis associated mainly to its late diagnosis. Cisplatin is an FDA approved ovarian cancer therapy and even though the therapy is initially promising, the patients mostly progress to resistance against cisplatin. The underlying mechanisms are complex and not very clearly understood. Using two different paired cell lines representing cisplatin-sensitive and the cisplatin-resistant ovarian cancer cells, the ES2 and the A2780 parental and cisplatin-resistant cells, we show an elevated proto-oncogene c-Myb in resistant cells. We further show down-regulated lncRNA NKILA in resistant cells with its de-repression in resistant cells when c-Myb is silenced. NKILA negatively correlates with cancer cell and invasion but has no effect on cellular proliferation or cell cycle. C-Myb activates NF-κB signaling which is inhibited by NKILA. The cisplatin resistant cells are also marked by upregulated stem cell markers, particularly LIN28A and OCT4, and downregulated LIN28A-targeted let-7 family miRNAs. Whereas LIN28A and downregulated let-7s individually de-repress c-Myb-mediated cisplatin resistance, the ectopic expression of let-7s attenuates LIN28A effects, thus underlying a c-Myb-NKILA-LIN28A-let-7 axis in cisplatin resistance of ovarian cancer cells that needs to be further explored for therapeutic intervention.

Blocking the interaction between circTNRC18 and LIN28A promotes trophoblast epithelial-mesenchymal transformation and alleviates preeclampsia.

Defects in migration and invasion caused by dysregulation of trophoblastic epithelial-mesenchymal transformation (EMT) play a vital role in preeclampsia (PE). We have previously shown that circTNRC18 inhibits the migration and EMT of trophoblasts; however, its role in PE remains unknown. Herein, we demonstrate that circTNRC18 interacts with an RNA-binding protein, lin-28 homolog A (LIN28A), and this interaction is enhanced in PE placental tissue. LIN28A overexpression suppresses circTNRC18-mediated inhibition of trophoblast migration, invasion, and EMT, whereas LIN28A knockdown promotes them. The intracellular distribution of LIN28A is regulated by circTNRC18, where it promotes the expression of insulin-like growth factor II by stabilizing its mRNA. circTNRC18 also promotes complex formation between GATA-binding factor 1 (GATA1) and sine oculis homeobox 1 (SIX1) by inhibiting LIN28A-GATA1 interaction. GATA1-SIX1 promotes transcription of grainyhead-like protein 2 homolog and circTNRC18-mediated regulation of cell migration and invasion. Moreover, blocking circTNRC18-LIN28A interaction with antisense nucleotides alleviates PE in a mouse model of reduced uterine perfusion pressure. Thus, targeting the circTNRC18-LIN28A regulatory axis may be a novel PE treatment method.

EZH2 Promotes Glioma Cell Proliferation, Invasion, and Migration via Mir-142-3p/KCNQ1OT1/HMGB3 Axis : Running Title: EZH2 Promotes Glioma cell Malignant Behaviors.

This study investigates the role and molecular mechanism of EZH2 in glioma cell proliferation, invasion, and migration. EZH2, miR-142-3p, lncRNA KCNQ1OT1, LIN28B, and HMGB3 expressions in glioma tissues and cells were determined using qRT-PCR or Western blot, followed by CCK-8 assay detection of cell viability, Transwell detection of invasion and migration, ChIP analysis of the enrichment of EZH2 and H3K27me3 on miR-142-3p promoter, dual-luciferase reporter assay and RIP validation of the binding of miR-142-3p-KCNQ1OT1 and KCNQ1OT1-LIN28B, and actinomycin D detection of KCNQ1OT1 and HMGB3 mRNA stability. A nude mouse xenograft model and a lung metastasis model were established. EZH2, KCNQ1OT1, LIN28B, and HMGB3 were highly expressed while miR-142-3p was poorly expressed in gliomas. EZH2 silencing restrained glioma cell proliferation, invasion, and migration. EZH2 repressed miR-142-3p expression by elevating the H3K27me3 level. miR-142-3p targeted KCNQ1OT1 expression, and KCNQ1OT1 bound to LIN28B to stabilize HMGB3 mRNA, thereby promoting its protein expression. EZH2 silencing depressed tumor growth and metastasis in nude mice via the miR-142-3p/KCNQ1OT1/HMGB3 axis. In conclusion, EZH2 curbed miR-142-3p expression, thereby relieving the inhibition of KCNQ1OT1 expression by miR-142-3p, enhancing the binding of KCNQ1OT1 to LIN28B, elevating HMGB3 expression, and ultimately accelerating glioma cell proliferation, invasion, and migration.

GNAI3 mediated by Lin28A regulates lipopolysaccharide-induced inflammation and osteogenic differentiation in periodontal stem cells by mediating the NF-κB/NLRP3 inflammasome pathway.

OBJECTIVES: The aim of this study was to investigate the regulatory role of G protein subunit alpha i3 (GNAI3) in periodontitis. DESIGN: Following the induction of human periodontal ligament stem cells (hPDLSCs) with lipopolysaccharide (LPS), the mRNA and protein expressions of GNAI3 and Lin28A were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot. The transfection efficiency of Oe-GNAI3 and sh-Lin28A was examined by virtue of RT-qPCR and western blot. With the application of ELISA and flow cytometry, the releases of inflammatory cytokines and cell apoptosis were appraised. Alkaline phosphatase (ALP) staining and alizarin red S (ARS) staining were conducted to evaluate osteogenic differentiation. Next, the binding ability of Lin28A with GNAI3 mRNA was estimated by radioimmunoprecipitation (RIP) assay while the stability of GNAI3 mRNA was assessed utilizing RT-qPCR. Western blot was employed for the measurement of inflammation-, apoptosis- and nuclear factor-kappaB (NF-κB)/NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome pathway-related proteins and osteogenic markers. RESULTS: The expression of GNAI3 was down-regulated in LPS-induced hPDLSCs. After the transfection with Oe-GNAI3, the inflammation and apoptosis in LPS-induced hPDLSCs were inhibited while osteogenic differentiation was promoted. Moreover, Lin28A could stabilize GNAI3 mRNA and Lin28A knockdown significantly reduced GNAI3 expression. Further experiments verified that the inhibitory effects of GNAI3 overexpression on LPS-induced cellular inflammation and cell apoptosis as well as the promotive effects on osteogenic differentiation in hPDLSCs were all partially counteracted by Lin28A depletion, which may possibly be mediated via the regulation of the NF-κB/NLRP3 inflammasome pathway. CONCLUSION: GNAI3 that mediated by Lin28A regulates the inflammation and osteogenic differentiation in LPS-induced hPDLSCs by mediating the NF-κB/NLRP3 inflammasome pathway.

Identification of small molecule inhibitors against Lin28/let-7 to suppress tumor progression and its alleviation role in LIN28-dependent glucose metabolism.

The reciprocal suppression of an RNA-binding protein LIN28 (human abnormal cell lineage 28) and miRNA Let-7 (Lethal 7) is considered to have a prime role in hepatocellular carcinoma (HCC). Though targeting this inhibition interaction is effective for therapeutics, it causes other unfavorable effects on glucose metabolism and increased insulin resistance. Hence, this study aims to identify small molecules targeting Lin28/let-7 interaction along with additional potency to improve insulin sensitivity. Of 22,14,996 small molecules screened by high throughput virtual screening, 6 molecules, namely 41354, 1558, 12437, 23837, 15710, and 8319 were able to block the LIN28 interaction with let-7 and increase the insulin sensitivity via interacting with PPARγ (peroxisome proliferator-activated receptors γ). MM-GBSA (Molecular Mechanics-Generalized Born Surface Area) analysis is used to re-score the binding affinity of docked complexes. Upon further analysis, it is also seen that these molecules have superior ADME (Absorption, Distribution, Metabolism, and Excretion) properties and form stable complexes with the targets for a significant period in a biologically simulated environment (Molecular Dynamics simulation) for 100 ns. From our results, we hypothesize that these identified 6 small molecules can be potential candidates for HCC treatment and the glucose metabolic disorder caused by the HCC treatment.

Inhibition of Let-7b-5p maturation by LIN28A promotes thermal skin damage repair after burn injury.

Burn injuries, especially severe ones, result in direct and indirect thermal damage to skin tissues, with a complex and slow wound healing process. Improper treatment can induce sustained inflammatory responses, causing systemic damage. Lin28A, a highly conserved RNA binding protein, was found to exert a significant effect on cell proliferation and wound repair. Lin28A exerts the functions through inhibiting the maturation of the let-7 family miRNAs. Herein, the roles of Lin28A and let-7b in thermal injury repair were investigated using a mouse thermal injury model and a human skin fibroblast (HSF) model for thermal injuries. Lin28A could inhibit the maturation of let-7b, thus participating in skin repair after burns. In the animal model, Lin28A was highly expressed after thermal injury. In the HSF model for thermal injuries, downregulation of Lin28A inhibited the proliferation, migration, and extracellular matrix (ECM) generation of fibroblasts. When let-7b was knocked down in HSFs, the impacts on fibroblast functions caused by downregulation of Lin28A were partially reversed. Moreover, let-7b overexpression might significantly attenuate the promotive effects of Lin28A upon thermal injury repair. Finally, AKT2 and IGF1R were the let-7b target genes within cells. These findings reveal that Lin28A might promote thermal injury repair in burn-injured skin by inhibiting the maturation of let-7b and improving HSF viability and functions, thus illustrating the critical effect of let-7b on burn wound healing and providing new therapeutic targets and strategies for burn treatment.

N6-methyladenosine modification of circMARK2 enhances cytoplasmic export and stabilizes LIN28B, contributing to the progression of Wilms tumor.

BACKGROUND: The potential involvement of circular RNAs (circRNAs) and N6-methyladenosine (m6A) modification in the progression of Wilms tumor (WT) has not been fully elucidated. This study investigates the regulatory mechanisms and clinical significance of m6A-modified circMARK2 and its role in WT progression. METHODS: We identified dysregulated circRNAs through deep sequencing and validated their expression by qRT-PCR in WT tissues. The biological functions of circMARK2 were assessed using clone formation, transwell migration, and orthotopic animal models. To dissect the underlying mechanisms, we employed RNA immunoprecipitation, RNA pull-down, dual-luciferase reporter assays, Western blotting, and immunofluorescence and immunohistochemical staining. RESULTS: CircMARK2, upregulated in WT tissues, was found to be m6A-modified and promoted cytoplasmic export. It facilitated WT progression by stabilizing LIN28B mRNA through the circMARK2/IGF2BP2 interaction. In vitro and in vivo studies demonstrated that circMARK2 enhances the malignant behavior of WT cells. Clinically, higher circMARK2 levels in tumor tissues of WT patients were linked to increased tumor aggressiveness and reduced survival rates. CONCLUSIONS: Our study provides the first comprehensive evidence that m6A-modified circMARK2 contributes to WT progression by enhancing LIN28B mRNA stability, promoting cellular aggressiveness. CircMARK2 emerges as a potential biomarker for prognosis and a promising target for therapeutic intervention in WT, underscoring the clinical relevance of m6A modification in pediatric renal cancer.

Direct reprogramming of non-limb fibroblasts to cells with properties of limb progenitors.

The early limb bud consists of mesenchymal limb progenitors derived from the lateral plate mesoderm (LPM). The LPM also gives rise to the mesodermal components of the flank and neck. However, the cells at these other levels cannot produce the variety of cell types found in the limb. Taking advantage of a direct reprogramming approach, we find a set of factors (Prdm16, Zbtb16, and Lin28a) normally expressed in the early limb bud and capable of imparting limb progenitor-like properties to mouse non-limb fibroblasts. The reprogrammed cells show similar gene expression profiles and can differentiate into similar cell types as endogenous limb progenitors. The further addition of Lin41 potentiates the proliferation of the reprogrammed cells. These results suggest that these same four factors may play pivotal roles in the specification of endogenous limb progenitors.