Pax6 Protein Research Articles

Shedding light on congenital aniridia: an in-depth study of two cases

Congenital aniridia is a rare ocular disorder characterized by the partial or complete absence of iris tissue. Although the classic form is associated with a range of ocular abnormalities, including foveal and optic nerve hypoplasia, nystagmus, and cataracts, it is the onset of glaucoma, cataracts, and keratopathy that most significantly impair vision in affected patients. Typically caused by mutations in the PAX6 gene, which encodes the paired box protein Pax-6, aniridia can also be associated with systemic conditions such as WAGR syndrome. This study emphasizes the importance of comprehensive ophthalmic examination and genetic testing in diagnosing and managing aniridia, particularly when associated with systemic conditions. Multidisciplinary management and regular follow-up are essential to monitor for potential complications, including Wilms' tumor, ensuring optimal care for affected patients.

Effects of miR-204-5p modulation on PAX6 regulation and corneal inflammation

Congenital aniridia is a rare eye disease characterized by loss of PAX6 protein leading to aniridia-associated keratopathy that significantly reduces vision. The miR-204-5p is a possible regulator of PAX6 function and here we evaluate its effect in multiple in vitro and in vivo models. In vitro, miR-204-5p overexpression suppressed vascular factor ANGPT1 in human limbal stem cells (T-LSC) and Pax6-knockdown LSC (mut-LSC), and in primary human limbal epithelial cells (LEC) at the gene and protein levels and following LPS stimulation. However, miR-204-5p inhibited VEGFA expression only in mut-LSCs and LPS-stimulated LEC. Also, miR-204-5p increased PAX6 expression in mut-LSC and differentiated corneal epithelial cells, but not in LEC. Topical miR-204-5p after LPS-induced keratitis in mice failed to suppress Vegfa, Angpt1, Il-1β, and Tnf-α or rescue Pax6 levels in contrast to in vitro results, although it significantly reduced the inflammatory infiltrate in the cornea. In Pax6Sey/+ aniridia mice, miR-204-5p did not rescue PAX6 levels or suppress Vegfa, Angpt1, or inhibit the ERK1/2 pathway. While short-term miR-204-5p treatment effectively suppresses VEGFA and ANGPT1 and enhances PAX6 expression in multiple corneal epithelia, effects are variable across primary and immortalized cells. Effects of longer-term in vivo treatment, however, require further study.

A diarylheptanoid derivative mediates glycogen synthase kinase 3β to promote the porcine muscle satellite cell proliferation: Implications for cultured meat production

Skeletal muscle stem cells, or satellite cells, are vital for cultured meat production, driving proliferation and differentiation to form muscle fibers in vitro. However, these abilities are often compromised after long-term in vitro culturing due to a loss of their stemness characteristics. Therefore, effective pharmacological agents that enhance satellite cell proliferation and maintain stemness ability are needed for optimal cell growth for cultured meat production. In this study, the effects of the identified glycogen synthase kinase 3β (GSK3β) inhibitors, ASPP 049, a diarylheptanoid isolated from Curcuma comosa rhizomes, and CHIR 99021 on porcine muscle satellite cell (PMSC) proliferation and Wnt/β-catenin signaling pathway were investigated. We found that both compounds enhanced cell viability and proliferation while preserving the stemness marker, as evidenced by increased expression of the skeletal muscle stem cell marker, Pax7 protein. Molecular dynamics simulations showed that ASPP 049 and CHIR 99021 exhibited differing binding affinities, primarily through hydrophobic interactions, suggesting potential for the design of more potent inhibitors in the future. Despite its weaker binding, ASPP 049 still showed significant effects on the regulation of the Wnt/β-catenin signaling pathway via increased phosphorylation of GSK3β at Ser9 and decreased the phosphorylation of β-catenin at Ser33, Ser37, and Thr41, thereby subsequently activating Wnt transcriptional activity. This study highlights the potential of ASPP 049 and CHIR 99021 to enhance PMSC proliferation and maintain stemness ability, offering a promising avenue for improving cultured meat production.

A novel PAX9 variant in a Chinese family with non-syndromic oligodontia and genotype-phenotype analysis of PAX9variants.

This study aimed to identifyPAX9variants in non-syndromic tooth agenesis families of China, as well as to analyze the genotype⁃phenotype of non-syndromic tooth agenesis caused by PAX9variants, which can provide a basis for the genetic diagnosis of tooth agenesis. We collected the data of 44 patients with non-syndromic oligodontia who underwent treatment at Stomatological Hospital of Hebei Medical University between 2018 and 2023. Whole-exome sequencing was performed on the peripheral blood of the proband and its core family members, and the variants were verified by Sanger sequencing. Pathogenicity analysis and function prediction of the variants were performed using bioinformatics tools. The correlation between the genotype of PAX9 variant and its corresponding phenotype was examined by reviewing 55 publications retrieved from PubMed. The studies involved 232 tooth agenesis patients with PAX9 variants. A novel PAX9 c.447delG (p.Pro150Argfs*62) and a reported PAX9 c.406C>T (p.Gln136*) were identified in two Chinese families. Through bioinformatics analysis and three-dimensional structural modeling, we postulated that the frameshift variant was pathogenic. The outcome was the premature cessation of PAX9 protein, which caused severe structural and functional deficiencies. Summarizing the PAX9 genotype-phenotype relationship revealed that patients carrying the PAX9 variant commonly led to loss of the second molars. We identified the novel PAX9 c.447delG (p.Pro150Argfs*62) in a Chinese family of non-syndromic oligodontia, expanding the known variant spectrum of PAX9. The most susceptible tooth position for PAX9 variants of tooth agenesis was the second molars and the deciduous molars during the deciduous dentition.

Duloxetine enhances PAX6 expression and suppresses innate immune responses in murine LPS-induced corneal inflammation

Background-aimPAX6 is a key regulator of eye development and epithelial homeostasis in the cornea. When deficient, chronic corneal inflammation, neovascularization and limbal stem cell deficiency can occur. Here we investigated the potential of duloxetine, a generic serotonin reuptake inhibitor that can upregulate PAX6 in vitro, for its in vivo activity in the context of corneal inflammation. MethodsDuloxetine tolerance was tested in a human limbal stem cell line and isogenic CRISPR-knockout PAX6+/− cells. C57BL/6-Wildtype mice were administered duloxetine eye drops at concentrations of 1 μM - 2 mM and tested for toxicity and corneal PAX6 expression. In LPS-induced corneal inflammation in mice, duloxetine's effect on PAX6 expression, corneal opacification and inflammatory responses were evaluated by in vivo corneal imaging, immunostaining, and whole-transcriptome microarray analysis. ResultsNo toxicity was observed in vitro for duloxetine concentrations up to 10μΜ. In vivo, duloxetine drops were well-tolerated up to 50 μM. Duloxetine drops at 10μΜ significantly upregulated PAX6 protein levels in the cornea by 30 % within 2 days. In the LPS model, duloxetine resulted in a sustained 33 % PAX6 protein upregulation in the cornea at 7 days, and in reduced opacity within 2 days, accompanied by a significant dampening of IL-17A signaling, neutrophil degranulation, microglial activation, macrophage markers, and MMP expression, despite non-significant changes in total inflammatory cell infiltration. ConclusionShort-term administration of a repurposed generic drug, duloxetine, upregulates PAX6 protein levels in the cornea of mice and exerts an anti-inflammatory activity by dampening innate immune responses.

Genome-Wide Identification and Evolutionary and Mutational Analysis of the Bos taurus Pax Gene Family.

Bos taurus is known for its tolerance of coarse grains, adaptability, high temperature, humidity, and disease resistance. Primarily, cattle are raised for their meat and milk, and pinpointing genes associated with traits relevant to meat production can enhance their overall productivity. The aim of this study was to identify the genome, analyze the evolution, and explore the function of the Pax gene family in B. taurus to provide a new molecular target for breeding in meat-quality-trait cattle. In this study, 44 Pax genes were identified from the genome database of five species using bioinformatics technology, indicating that the genetic relationships of bovids were similar. The Pax3 and Pax7 protein sequences of the five animals were highly consistent. In general, the Pax gene of the buffalo corresponds to the domestic cattle. In summary, there are differences in affinity between the Pax family genes of buffalo and domestic cattle in the Pax1/9, Pax2/5/8, Pax3/7, and Pax4/6 subfamilies. We believe that Pax1/9 has an effect on the growth traits of buffalo and domestic cattle. The Pax3/7 gene is conserved in the evolution of buffalo and domestic animals and may be a key gene regulating the growth of B. taurus. The Pax2/5/8 subfamily affects coat color, reproductive performance, and milk production performance in cattle. The Pax4/6 subfamily had an effect on the milk fat percentage of B. taurus. The results provide a theoretical basis for understanding the evolutionary, structural, and functional characteristics of the Pax family members of B. taurus and for molecular genetics and the breeding of meat-production B. taurus species.

In ovo betaine injection improves breast muscle growth in newly hatched goslings through FXR/IGF-2 pathway

Betaine has been shown to enhance growth performance and increase breast muscle yield in ducks and broilers through various mechanisms, including the modification of DNA methylation. However, the impact of in ovo betaine injection on muscle growth in newly hatched goslings remains unclear. In this study, fifty eggs were injected with saline or betaine at 7.5 mg/egg prior to incubation, and the subsequent effects on breast muscle growth in the newly hatched goslings were investigated. Betaine significantly increased (P < 0.05) the hatch weight, breast muscle weight, and breast muscle index, accompanied by an augmentation in muscle bundle cross-sectional area. Concurrently, betaine significantly upregulated (P < 0.05) the expression levels of myogenic regulatory factors, including myogenin (MyoG) and paired box 7 (Pax7) both mRNA and protein, while downregulating (P < 0.05) the mRNA and protein levels of myostatin (MSTN). Histological analysis revealed a higher abundance of proliferating cell nuclear antigen (PCNA) and Pax7 immune-positive cells in the breast muscle of the betaine group, consistent with elevated PCNA and Pax7 mRNA and protein levels. Additionally, significantly increased (P < 0.05) contents of insulin-like growth factor 1 (IGF-1) and insulin-like growth factor 2 (IGF-2) were observed in the breast muscle of the betaine group, so was mRNA expression of IGF-1, IGF-2, and insulin-like growth factor 1 receptor (IGF-1R). Betaine also significantly in8creased (P < 0.05) global DNA methylation of the breast muscle, accompanied by enhanced mRNA and protein levels of methionine cycle and DNA methylation-related enzymes, Interestingly, the promoter regions of IGF-1, IGF-2, and IGF-1R genes were significantly hypomethylated (P < 0.05). Moreover, in ovo betaine injection significantly upregulated (P < 0.05) the protein level of farnesoid X receptor (FXR) in breast muscle and FXR binding to the promoter of IGF-2 gene. These findings suggest that in ovo betaine injection promotes breast muscle growth during embryonic development in goslings through the FXR-mediated IGF-2 pathway, ultimately improving hatch weight and breast muscle weight.

Heparin-Binding Epidermal-like Growth Factor (HB-EGF) Reduces Cell Death in an Organoid Model of Retinal Damage

In zebrafish and various mammalian species, HB-EGF has been shown to promote Müller glia proliferation and activation of repair mechanisms that have not been fully investigated in human retina. In the current study, 70- to 90-day-old human retinal organoids were treated with 20 μM 4-hydroxytamoxifen (4-OHT), and CRX, REC, NRL, PAX6, VIM, GFAP, and VSX2 gene and protein expression were assessed at various times points after treatment. Organoids with or without 4-OHT-induced damage were then cultured with HB-EGF for 7 days. We showed that 20 μM 4-OHT caused a reduction in the number of recoverin-positive cells; an increase in the number of TUNEL-positive cells; and downregulation of the photoreceptor gene markers CRX, NRL, and REC. Culture of organoids with HB-EGF for 7 days after 4-OHT-induced damage caused a marked reduction in the number of TUNEL-positive cells and small increases in the number of Ki67-positive cells and PAX6 and NOTCH1 gene expression. The current results suggest that treatment of human ESC-derived retinal organoids with 4-OHT may be used as a model of retinal degeneration in vitro. Furthermore, HB-EGF treatment of human retinal organoids increases proliferating Müller cells, but only after 4-OHT induced damage, and may be an indication of Muller reactivity in response to photoreceptor damage. Further studies will aim to identify factors that may induce Müller cell-mediated regeneration of the human retina, aiding in the development of therapies for retinal degeneration.

Utility of immunocytochemistry in diagnosing abdominopelvic washings from patients undergoing radical surgery for endometrial cancer.

This study aimed to explore the efficacy of immunocytochemistry in diagnosing abdominopelvic washings (APWs) and evaluate the superiority of cytology combined with immunocytochemistry over cytology alone. Data on APW cytology and available cell blocks from patients who underwent radical surgery for endometrial cancer between January 2021 and December 2022 were reviewed. Cytology was re-evaluated according to a five-tier system. Immunocytochemistry analysis for targets such as Sry box transcription factor 1(SOX17), Paired box gene 2 (Pax-2) protein, Phosphatase and tensin (PTEN), and β-catenin was performed on each case with non-negative cytology. Mismatch repair (MMR) protein and P53 immunocytochemistry analyses were performed using cell blocks from cases with abnormal MMR or P53 expression in their primary lesion. The accuracies of cytology combined with immunocytochemistry and cytology alone were calculated. Overall, 126 patients were included in this study, 18 of whom demonstrated non-negative cytology of APW. Cell blocks were successfully prepared for 16 cases. SOX17 positivity was observed in 16 cases, including 1 of serous carcinoma, 1 of clear cell carcinoma, and 14 of endometrioid carcinoma (EC). Loss of Pax-2 and PTEN expression was observed in the APWs of the 14 patients with EC. MMR deficiency was noted in two patients with EC, and P53 mutation was noted in another two patients with EC. Compared with 10 metastatic carcinomas (10/18, 55.56%) diagnosed by cytology alone, 15 malignant APWs (15/18, 83.33%) were confirmed through combination cytology and immunocytochemistry. APWs were more likely to be observed in cases with more than half myometrial invasion than those with no or less than half myometrial invasion (P = 0.0067). The probability of malignant APW occurrence was slightly elevated in cases of EC exhibiting microcystic, elongated, and fragmented(MELF) infiltrative growth (P = 0.039). SOX17 is a useful Müllerian marker for distinguishing endometrial epithelium in APW. Loss of Pax-2 and PTEN expression offers evidence of metastatic endometrial carcinoma. Furthermore, positive APWs retained molecular features similar to primary lesions. The use of multiple immunocytochemical markers can effectively enhance the diagnostic efficiency of APWs.

A dual-color PAX7 and MYF5 in vivo reporter to investigate muscle stem cell heterogeneity in regeneration and aging

Increasing evidence suggests that the muscle stem cell (MuSC) pool is heterogeneous. In particular, a rare subset of PAX7-positive MuSCs that has never expressed the myogenic regulatory factor MYF5 displays unique self-renewal and engraftment characteristics. However, the scarcity and limited availability of protein markers make the characterization of these cells challenging. Here, we describe the generation of StemRep reporter mice enabling the monitoring of PAX7 and MYF5 proteins based on equimolar levels of dual nuclear fluorescence. High levels of PAX7 protein and low levels of MYF5 delineate a deeply quiescent MuSC subpopulation with an increased capacity for asymmetric division and distinct dynamics of activation, proliferation, and commitment. Aging primarily reduces the MYF5Low MuSCs and skews the stem cell pool toward MYF5High cells with lower quiescence and self-renewal potential. Altogether, we establish the StemRep model as a versatile tool to study MuSC heterogeneity and broaden our understanding of mechanisms regulating MuSC quiescence and self-renewal in homeostatic, regenerating, and aged muscles.

Photobiomodulation mitigates Bothrops jararacussu venom-induced damage in myoblast cells by enhancing myogenic factors and reducing cytokine production.

Photobiomodulation has exhibited promise in mitigating the local effects induced by Bothrops snakebite envenoming; however, the mechanisms underlying this protection are not yet fully understood. Herein, the effectiveness of photobiomodulation effects on regenerative response of C2C12 myoblast cells following exposure to Bothrops jararacussu venom (BjsuV), as well as the mechanisms involved was investigated. C2C12 myoblast cells were exposed to BjsuV (12.5 μg/mL) and irradiated once for 10 seconds with laser light of 660 nm (14.08 mW; 0.04 cm2; 352 mW/cm2) or 780 nm (17.6 mW; 0.04 cm2; 440 mW/ cm2) to provide energy densities of 3.52 and 4.4 J/cm2, and total energies of 0.1408 and 0.176 J, respectively. Cell migration was assessed through a wound-healing assay. The expression of MAPK p38-α, NF-Кβ, Myf5, Pax-7, MyoD, and myogenin proteins were assessed by western blotting analysis. In addition, interleukin IL1-β, IL-6, TNF-alfa and IL-10 levels were measured in the supernatant by ELISA. The PBM applied to C2C12 cells exposed to BjsuV promoted cell migration, increase the expression of myogenic factors (Pax7, MyF5, MyoD and myogenin), reduced the levels of proinflammatory cytokines, IL1-β, IL-6, TNF-alfa, and increased the levels of anti-inflammatory cytokine IL-10. In addition, PBM downregulates the expression of NF-kB, and had no effect on p38 MAKP. These data demonstrated that protection of the muscle cell by PBM seems to be related to the increase of myogenic factors as well as the modulation of inflammatory mediators. PBM therapy may offer a new therapeutic strategy to address the local effects of snakebite envenoming by promoting muscle regeneration and reducing the inflammatory process.

A novel frameshift mutation in SOX10 gene induced Waardenburg syndrome type II.

To explore the molecular etiology of Waardenburg syndrome type II (WS2) in a family from Yunnan province, China. A total of 406 genes related to hereditary hearing loss were sequenced using next-generation sequencing. DNA samples were isolated from the peripheral blood DNA of probands. Those pathogenic mutations detected by next-generation sequencing in probands and their parents were validated by Sanger sequencing. The conservatism of variation sites in genes was also analyzed. The protein expression was detected by flow cytometry. A heterozygous mutation c.178delG (p.D60fs*49) in the SOX10 gene was identified in the proband, which is a frameshift mutation and may cause protein loss of function and considered to be a pathogenic mutation. This was determined to be a de novo mutation because her family were demonstrated to be wild-type and symptom free. SOX10, FGFR3, SOX2, and PAX3 protein levels were reduced as determined by flow cytometry. A novel frameshift mutation in SOX10 gene was identified in this study, which may be the cause of WS2 in proband. In addition, FGFR3, SOX2, and PAX3 might also participate in promoting the progression of WS2.

PAX6 protein in neuromasts of the lateral line system of salamanders (Eurycea).

PAX6 is well known as a transcription factor that drives eye development in animals as widely divergent as flies and mammals. In addition to its localization in eyes, PAX6 expression has been reported in the central nervous system, the pancreas, testes, Merkel cells, nasal epithelium, developing cells of the inner ear, and embryonic submandibular salivary gland. Here we show that PAX6 also appears to be present in the mechanosensory neuromasts of the lateral line system in paedomorphic salamanders of the genus Eurycea. Using immunohistochemistry and confocal microscopy to examine a limited number of larvae of two species, listed by the United States of America's federal government as threatened (E. nana) or endangered (E. rathbuni), we found that anti-PAX6 antibody labeled structures that were extranuclear, and labeling was most intense in the apical appendages of the hair cells of the neuromast. This extranuclear localization raises the possibility of an as yet undescribed function for PAX6 as a cytoskeleton-associated protein.

Multi ‐ omics studies of eye and lens development

Early eye development involves formation of a symmetric pair of optic vesicles from the anterior neuroectoderm and parallel formation of closely apposed lens placodes. Their reciprocal invaginations generate the 3D‐foundation of the optic cups. Embryonic lens development is initiated within the border between the anterior neuroectoderm and naïve ectoderm, called the anterior pre‐placodal region. The earliest stages of lens development require coordinated actions of DNA‐binding transcription factor Pax6, signalling growth factor BMP4 and a pair of chromatin remodelling enzymes p300 and CBP. Studies in model vertebrates postulated a common Pax6+ progenitor cell population to generate both the lens and olfactory placodes. Recent progress in technologies to probe chromatin structure, landscape of transcription factor binding, DNA methylation, coding (mRNA) and noncoding (e.g. eRNAs and ncRNAs) transcriptomes and chromatin conformation have been shown to generate unprecedented mechanistic insights into the earliest cell fate decisions and tissue organization. To examine lens development at E8.5, E9.5 and E10.5 mouse embryos, single cell RNA‐seq (scRNA‐seq) experiments using the 10XGenomics Chromium platform were conducted. E9.5 Pax6 null embryos and controls were also included. Whole genome bisulfite sequencing (WGBS) was performed in E14.5 and P0.5 microdissected mouse lenses to map DNA methylation and integrate the data with corresponding ATAC‐ and RNA‐seq data sets. Open chromatin and DNA methylation changes were defined through identification of differentially accessible regions (DARs), unmethylated/low methylated regions (UMRs/LMRs) coupled with differential gene expression during lens differentiation. To probe 3D‐organization of lens chromatin and to identify temporally and spatially regulated lens‐specific distal enhancers, Hi‐C was used in conjunction with ChIP‐seq analysis of transcription factor CTCF in microdissected newborn lenses. Previous ChIP‐seq data using whole newborn lenses include H3K27ac peaks to identify super‐enhancers. Pax6 proteins were found both in open and closed chromatin domains, including both closed and methylated regions. In vitro binding of Pax6 proteins was not inhibited by 5‐methylcytosines within one or two CpG dinucleotides present in the Pax6 binding sites. In summary, cell fate decisions are governed by complex changes in chromatin landscape controlled by sequence‐specific DNA‐binding transcription factors and their recruitment of chromatin remodelling complexes. A combination of different –omics is a powerful approach to examine molecular mechanisms governing eye development. These studies also reveal additional levels of genetic code complexity and stimulate follow up mechanistic studies of the individual cellular and molecular processes of lens morphogenesis and their underlying GRNs and identification of cataract‐causing mutation in non‐coding regulatory sequences.

Vitamin C regulates skeletal muscle post-injury regeneration by promoting myoblast proliferation through its direct interaction with the Pax7 protein.

Previous studies have shown that vitamin C (VC), an essential vitamin for the human body, can promote the differentiation of muscle satellite cells (MuSCs) in vitro and play an important role in skeletal muscle post-injury regeneration. However, the molecular mechanism of VC regulating MuSC proliferation has not been elucidated. In this study, the role of VC in promoting MuSC proliferation and its molecular mechanism were explored using cell molecular biology and animal experiments. The results showed that VC accelerates the progress of skeletal muscle post-injury regeneration by promoting MuSC proliferation in vivo. VC can also promote skeletal muscle regeneration in the case of atrophy. Using the C2C12 myoblast murine cell line, we observed that VC also stimulated cell proliferation. In addition, after an in vitro study establishing the occurrence of a physical interaction between VC and Pax7, we observed that VC also upregulated the total and nuclear Pax7 protein levels. This mechanism increased the expression of Myf5 (Myogenic Factor 5), a Pax7 target gene. This study establishes a theoretical foundation for understanding the regulatory mechanisms underlying VC-mediated MuSC proliferation and skeletal muscle regeneration. Moreover, it develops the application of VC in animal muscle nutritional supplements and treatment of skeletal muscle-related diseases.

Identification of duloxetine to treat aniridia‐related keratopathy: Link to inflammation?

Haploinsufficiency of PAX6 in humans is the main cause of congenital aniridia, a rare eye disease characterized by iris hypoplasia and reduced visual acuity. Patients have also progressive disorders including aniridia‐related keratopathy (ARK), caused by a combination of factors including limbal stem‐cell deficiency, impaired healing response, abnormal differentiation, and infiltration of conjunctival cells onto the corneal surface. It usually begins in the first decade of life resulting in recurrent corneal erosions, sub‐epithelial fibrosis with corneal decompensation and opacification. Unfortunately, current treatment options for aniridia patients are currently limited. There is no in vitro cellular model of AKT needed for drug/therapeutic tools screening and validation. We used genome editing (CRISPR/Cas9) to introduce a nonsense mutation into one allele of the PAX6 gene in limbal stem cells.The mutated cells displayed reduced cell proliferation and cell migration but enhanced cell adhesion. Known PAX6 targets expression was also altered. Of interest, recombinant PAX6 protein was sufficient to rescue the phenotype. By High Throughput Screening of a FDA‐approved library, we identified Duloxetine, a selective serotonin and norepinephrine reuptake inhibitor antidepressant, that rescued both PAX6 endogenous protein level and altered cell migration of the mutant limbal stem cells, through specific inhibition of the ERK/MEK pathway. Furthermore, we found that Duloxetine modulates inflammation through activation of Pax6, strongly suggesting that Pax6 could be a modulator of neuroinflammation. Since Duloxetine is already used as anti‐psychotropic drugs, its repurposed use to treat topically aniridia eye and other ocular inflammatory diseases could become realistic.

Identification of duloxetine to treat aniridia‐related keratopathy: Link to inflammation?

Haploinsufficiency of PAX6 in humans is the main cause of congenital aniridia, a rare eye disease characterized by iris hypoplasia and reduced visual acuity. Patients have also progressive disorders including aniridia‐related keratopathy (ARK), caused by a combination of factors including limbal stem‐cell deficiency, impaired healing response, abnormal differentiation, and infiltration of conjunctival cells onto the corneal surface. It usually begins in the first decade of life resulting in recurrent corneal erosions, sub‐epithelial fibrosis with corneal decompensation and opacification. Unfortunately, current treatment options for aniridia patients are currently limited. There is no in vitro cellular model of AKT needed for drug/therapeutic tools screening and validation. We used genome editing (CRISPR/Cas9) to introduce a nonsense mutation into one allele of the PAX6 gene in limbal stem cells.The mutated cells displayed reduced cell proliferation and cell migration but enhanced cell adhesion. Known PAX6 targets expression was also altered. Of interest, recombinant PAX6 protein was sufficient to rescue the phenotype. By High Throughput Screening of a FDA‐approved library, we identified Duloxetine, a selective serotonin and norepinephrine reuptake inhibitor antidepressant, that rescued both PAX6 endogenous protein level and altered cell migration of the mutant limbal stem cells, through specific inhibition of the ERK/MEK pathway. Furthermore, we found that Duloxetine modulates inflammation through activation of Pax6, strongly suggesting that Pax6 could be a modulator of neuroinflammation. Since Duloxetine is already used as anti‐psychotropic drugs, its repurposed use to treat topically aniridia eye and other ocular inflammatory diseases could become realistic.

Discovery of Novel Stimulators of Pax7 and/or MyoD: Enhancing the Efficacy of Cultured Meat Production through Culture Media Enrichment.

The principles of myogenesis play crucial roles in the production of cultured meat, and identifying protein stimulators associated with myogenesis holds great potential to enhance the efficiency of this process. In this study, we used surface plasmon resonance (SPR)-based screening of a natural product library to discover ligands for Pax7 and MyoD, key regulators of satellite cells (SCs), and performed cell-based assays on Hanwoo SCs (HWSCs) to identify substances that promote cell proliferation and/or differentiation. Through an SPR analysis, we found that six chemicals, including one Pax7+/MyoD- chemical, four Pax7+/MyoD+ chemicals, and one Pax7-/MyoD+ chemical, bound to Pax7 and/or MyoD proteins. Among four Pax7+/MyoD+ chemicals, parthenolide (0.5 and 1 µM) and rutin (100 and 200 µM) stimulated cell proliferation in the medium with 10% FBS similar to the medium with 20% FBS, without affecting differentiation. Adenosine, a Pax7-/MyoD+ chemical, accelerated differentiation. These chemicals could be potential additives to reduce the reliance of FBS required for HWSC proliferation and differentiation in cultured meat production.

Papillary renal neoplasm with reverse polarity: a clinicopathologic study of 43 cases with a focus on the expression of KRAS signaling pathway downstream effectors

Papillary renal neoplasm with reverse polarity (PRNRP) is a renal tumor with frequent KRAS mutations. In this study, we aimed to report the clinical, histological, and immunohistochemical characteristics of PRNRP and the protein expression of various KRAS signaling pathway downstream effectors in PRNRP. PRNRP samples from patients who underwent surgical resection at Seoul National University Hospital over an 11-year period (January 2011 to December 2021) were analyzed. We identified 43 PRNRPs, defined as papillary renal tumors with a thin papillary architecture, eosinophilic finely granular cytoplasm, and apical nuclear position. Immunohistochemistry revealed typical characteristics of PRNRP, including exclusively positive GATA3 (43/43); highly positive L1CAM (43/43), PAX8 (43/43), and EMA (43/43); and low positive AMACR (4/43), RCC (1/43), and vimentin (1/43). KRAS signaling pathway effectors, such as p-ERK, RalA, and RalB, were highly expressed in PRNRP compared to papillary renal cell carcinoma (pRCC) with low or high nuclear grade (P<.001, all). Compared to pRCC with high nuclear grade, patients with PRNRP exhibited significantly longer progression-free survival (P<.001). PRNRP showed the best clinical outcome, with no disease progression in any of the cases. Our study analyzed the largest number of PRNRP cases and is the first to analyze the association between PRNRP and the KRAS downstream signaling pathway. PRNRP was found at a high frequency among all papillary renal tumors (43/207) and demonstrated a very good prognosis. PRNRP showed high GATA3, L1CAM, PAX8, and EMA protein expression as well as high p-ERK, RalA, and RalB protein expression.

Production and limbal lineage commitment of aniridia patient-derived induced pluripotent stem cells.

Congenital aniridia is caused by heterozygous mutations on the PAX6 gene leading to reduced amount of PAX6 protein (haploinsufficiency), abnormal eye development and aniridia-associated keratopathy (AAK). This progressive corneal opacification resembles late-onset limbal stem cell (LSC) deficiency, leading to disrupted corneal epithelial renewal. The factors leading to AAK are not known and defects in native LSC differentiation and/or features leading to ocular surface dysfunction like inflammation and loss of innervation could contribute to development of AAK. Here, we produced induced pluripotent stem cells (hiPSC) from three AAK patients and examined whether PAX6 haploinsufficiency affects LSC lineage commitment. During LSC differentiation, characterization of the AAK lines showed lowered PAX6 expression as compared to wild type (WT) controls and expression peak of PAX6 during early phase of differentiation was detected only in the WT hiPSC lines. Whether it reflects developmental regulation remains to be studied further. Nevertheless, the AAK-hiPSCs successfully differentiated towards LSC lineage, in line with the presence of LSCs in young patients before cell loss later in life. In addition, patient specific LSCs showed similar wound healing capacity as WT cells. However, extensive batch-related variation in the LSC marker expression and wound healing efficacy was detected without clear correlation to AAK. As development and maintenance of corneal epithelium involves an interplay between LSCs and their environment, the AAK-hiPSCs generated here can be further used to study the crosstalk between LSCs and limbal niche including e.g. corneal immune cells, stroma cells and neurons.