The role of dermal fibroblasts in autoimmune skin diseases.

Fibroblasts are an important subset of mesenchymal cells in maintaining skin homeostasis and resisting harmful stimuli. Meanwhile, fibroblasts modulate immune cell function by secreting cytokines, thereby implicating their involvement in various dermatological conditions such as psoriasis, vitiligo, and atopic dermatitis. Recently, variations in the subtypes of fibroblasts and their expression profiles have been identified in these prevalent autoimmune skin diseases, implying that fibroblasts may exhibit distinct functionalities across different diseases. In this review, from the perspective of their fundamental functions and remarkable heterogeneity, we have comprehensively collected evidence on the role of fibroblasts and their distinct subpopulations in psoriasis, vitiligo, atopic dermatitis, and scleroderma. Importantly, these findings hold promise for guiding future research directions and identifying novel therapeutic targets for treating these diseases.

Exosomes containing miR-1469 regulate natural killer cells by targeting CD122 in non-segmental vitiligo.

BACKGROUND: Plasma exosomal microRNAs (miRNAs) have been used as potential biomarkers for various diseases and have been investigated for their possible involvement in the pathogenesis of vitiligo. However, the miRNA expression profile of plasma exosomes in patients with non-segmental vitiligo (NSV) has not been determined yet. OBJECTIVE: To screen differentially expressed microRNAs in plasma exosomes derived from patients with NSV and explore their roles in the pathogenesis of NSV. METHODS: High-throughput sequencing was performed to determine the expression profiles of exosomal miRNAs in NSV. The effect of upregulated miR-1469 in NSV circulating exosomes on natural killer (NK) cells was further investigated using various molecular biological techniques. RESULTS: MiR-1469 was identified as a candidate biomarker whose expression was significantly increased in circulating exosomes of NSV patients. Circulating exosomes were internalized by NK cells and increased NK cell proliferation viability and IFN-γ secretion capacity delivering miR-1469. Further studies revealed that the upregulation of CD122, the predicted target of miR-1469, could partially reverse the effect of miR-1469 on natural killer cells. CONCLUSION: Alterations in plasma exosomal cargo occur in NSV and appear to contribute to NK cell dysfunction. Exosomal miR-1469 may be a biomarker of disease activity and could be used as a therapeutic drug target against innate immunity in NSV patients. The present study provides new insights into the role of exosomal miRNAs in NSV and suggests a novel miR-1469-CD122-IFN-γ pathway of NK cell underlying pathogenesis of NSV.

Tildrakizumab for moderate-to-severe plaque psoriasis in Chinese patients: A 12-week randomized placebo-controlled phase III trial with long-term extension.

BACKGROUND: There is a need for effective and safe therapies for psoriasis that provide sustained benefits. The aim of this study was to assess the efficacy and safety of tildrakizumab, an anti-interleukin-23p19 monoclonal antibody, for treating moderate-to-severe plaque psoriasis in Chinese patients. METHODS: In this multi-center, double-blind, phase III trial, patients with moderate-to-severe plaque psoriasis were enrolled and randomly assigned (1:1) to receive subcutaneous tildrakizumab 100 mg or placebo at weeks 0 and 4. Patients initially assigned to placebo were switched to receive tildrakizumab at weeks 12, 16, and every 12 weeks thereafter. Patients in the tildrakizumab group continued with tildrakizumab at week 16, and every 12 weeks until week 52. The primary endpoint was the Psoriasis Area and Severity Index (PASI 75) response rate at week 12. RESULTS: At week 12, tildrakizumab demonstrated significantly higher PASI 75 response rates (66.4% [73/110] vs. 12.7% [14/110]; difference, 51.4% [95% confidence interval (CI), 40.72, 62.13]; P <0.001) and Physician's Global Assessment (60.9% [67/110] vs. 10.0% [11/110]; difference, 49.1% [95% CI, 38.64, 59.62]; P <0.001) compared to placebo. PASI 75 response continued to improve over time in both tildrakizumab and placebo-switching to tildrakizumab groups, reaching maximal efficacy after 28 weeks (86.8% [92/106] vs . 82.4% [89/108]) and maintained up to 52 weeks (91.3% [95/104] vs . 87.4% [90/103]). Most treatment-emergent adverse events were mild and not related to tildrakizumab. CONCLUSION: Tildrakizumab demonstrated durable efficacy through week 52 and was well tolerated in Chinese patients with moderate-to-severe plaque psoriasis. TRIAL REGISTRATION: ClinicalTrials.gov , NCT05108766.

Clinical features and biomarker differences of severe intrinsic and extrinsic atopic dermatitis.

OBJECTIVES: Atopic dermatitis (AD) can be classified into intrinsic AD(IAD) and extrinsic AD(EAD). However, the differences in clinical features and pathogenesis between these two subtypes of AD are currently unclear. This study aimed to analyse the differences in clinical features and peripheral blood biomarkers between Chinese patients with severe IAD and EAD in order to elucidate the physiopathogenesis of AD. MATERIALS AND METHODS: A total of 316 hospitalised patients definitively diagnosed with severe AD were included in this study. There were 72 cases of severe IAD and 244 cases of severe EAD. The clinical features of the patients were recorded in details. Serum total IgE, IgA, IgG, IgM, complementC3/C4, peripheral blood cell counts, lactate dehydrogenase (LDH), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), IL-2R, IL-6, IL-8, and TNF-α in AD patients and 60 age-matched healthy controls were analysed. IAD and EAD had similar severity/Scoring Atopic Dermatitis (SCORAD) scores. RESULTS: Compared with healthy controls, IAD patients had significantly higher total IgE, eosinophils, monocytes, LDH, CRP, IL-2R, IL-6, IL-8 and TNF-α, and lower IgM and C4. EAD patients had significantly higher total IgE, IgA, eosinophils, white blood cell (WBC) counts, neutrophils, monocytes, basophils, LDH, CRP, IL-2R, IL-6, IL-8, TNF-α and lower IgM than healthy controls. IAD patients had a higher percentage of rural/urban living and female/male, a shorter course of disease and lower total IgE, eosinophils, WBC counts, neutrophils, monocytes, basophils, LDH, IgG and C4 than EAD patients. SCORAD scores, eosinophils, LDH expression levels increased with total IgE uniquely in patients with EAD. CONCLUSIONS: IAD and EAD exhibit specific clinical features and molecular changes. IAD has a more complex physiopathogenesis, and deserves further investigation.

Exosomal miRNAs in autoimmune skin diseases.

Exosomes, bilaterally phospholipid-coated small vesicles, are produced and released by nearly all cells, which comprise diverse biological macromolecules, including proteins, DNA, RNA, and others, that participate in the regulation of their biological functions. An increasing number of studies have revealed that the contents of exosomes, particularly microRNA(miRNA), play a significant role in the pathogenesis of various diseases, including autoimmune skin diseases. MiRNA is a class of single-stranded non-coding RNA molecules that possess approximately 22 nucleotides in length with the capability of binding to the untranslated as well as coding regions of target mRNA to regulate gene expression precisely at the post-transcriptional level. Various exosomal miRNAs have been found to be significantly expressed in some autoimmune skin diseases and involved in the pathogenesis of conditions via regulating the secretion of crucial pathogenic cytokines and the direction of immune cell differentiation. Thus, exosomal miRNAs might be promising biomarkers for monitoring disease progression, relapse and reflection to treatment based on their functions and changes. This review summarized the current studies on exosomal miRNAs in several common autoimmune skin diseases, aiming to dissect the underlying mechanism from a new perspective, seek novel biomarkers for disease monitoring and lay the foundation for developing innovative target therapy in the future.

1,25-Dihydroxyvitamin D3 Provides Benefits in Vitiligo Based on Modulation of CD8+ T Cell Glycolysis and Function.

Vitiligo is a common autoimmune skin disease caused by autoreactive CD8+ T cells. The diverse effects of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] on immune cell metabolism and proliferation have made it an interesting candidate as a supporting therapeutic option in various autoimmune diseases. This study aimed to elucidate the immunomodulatory effects of 1,25(OH)2D3 in vitiligo. Cross-sectional relationships between serum 1,25(OH)2D3 levels and disease characteristics were investigated in 327 patients with vitiligo. The immunomodulatory and therapeutic effects of 1,25(OH)2D3 were then investigated in vivo and in vitro, respectively. We found that 1,25(OH)2D3 deficiency was associated with hyperactivity of CD8+ T cells in the vitiligo cohort. In addition, 1,25(OH)2D3 suppressed glycolysis by activating the AMP-activated protein kinase (AMPK) signaling pathway, thereby inhibiting the proliferation, cytotoxicity and aberrant activation of CD8+ T cells. Finally, the in vivo administration of 1,25(OH)2D3 to melanocyte-associated vitiligo (MAV) mice reduced the infiltration and function of CD8+ T cells and promoted repigmentation. In conclusion, 1,25(OH)2D3 may serve as an essential biomarker of the progression and severity of vitiligo. The modulation of autoreactive CD8+ T cell function and glycolysis by 1,25(OH)2D3 may be a novel approach for treating vitiligo.

Development of Mandarin Lexical Tone Identification in Noise and Its Relation With Working Memory.

PURPOSE: This study aimed to examine the developmental trajectory of Mandarin tone identification in quiet and two noisy conditions: speech-shaped noise (SSN) and multitalker babble noise. In addition, we evaluated the relationship between tonal identification development and working memory capacity. METHOD: Ninety-three typically developing children aged 5-8 years and 23 young adults completed categorical identification of two tonal continua (Tone 1-4 and Tone 2-3) in quiet, SSN, and babble noise. Their working memory was additionally measured using auditory digit span tests. Correlation analyses between digit span scores and boundary widths were performed. RESULTS: Six-year-old children have achieved the adultlike ability of categorical identification of Tone 1-4 continuum under both types of noise. Moreover, 6-year-old children could identify Tone 2-3 continuum as well as adults in SSN. Nonetheless, the child participants, even 8-year-olds, performed worse when tokens from Tone 2-3 continuum were masked by babble noise. Greater working memory capacity was associated with better tone identification in noise for preschoolers aged 5-6 years; however, for school-age children aged 7-8 years, such correlation only existed in Tone 2-3 continuum in SSN. CONCLUSIONS: Lexical tone perception might take a prolonged time to achieve adultlike competence in babble noise relative to SSN. Moreover, a significant interaction between masking type and stimulus difficulty was found, as indicated by Tone 2-3 being more susceptible to interference from babble noise than Tone 1-4. Furthermore, correlations between working memory capacity and tone perception in noise varied with developmental stage, stimulus difficulty, and masking type.

Circulating Exosomal miR-493-3p Affects Melanocyte Survival and Function by Regulating Epidermal Dopamine Concentration in Segmental Vitiligo.

Circulating exosomal microRNAs have been used as potential biomarkers for various disorders. However, to date, the microRNA expression profile of circulating exosomes in patients with segmental vitiligo (SV) has not been identified. Thus, we aimed to identify the expression profile of circulating exosomal microRNAs and investigate their role in the pathogenesis of SV. Our study identified the expression profile of circulating exosomal microRNAs in SV and selected miR-493-3p as a candidate biomarker whose expression is significantly increased in circulating exosomes and perilesions in patients with SV. Circulating exosomes were internalized by human primary keratinocytes and increased dopamine secretion in vitro. Furthermore, miR-493-3p overexpression in keratinocytes increased dopamine concentration in the culture supernatant, which led to a significant increase in ROS and melanocyte apoptosis as well as a decrease in melanocyte proliferation and melanin synthesis in the coculture system by targeting HNRNPU. We also confirmed that HNRNPU could bind to and regulate COMT, a major degradative enzyme of dopamine. Hence, circulating exosomal miR-493-3p is a biomarker for SV, and the miR-493-3p/HNRNPU/COMT/dopamine axis may contribute to melanocyte dysregulation in the pathogenesis of SV.

ABCB6 knockdown suppresses melanogenesis through the GSK3-ß/ß-catenin signaling axis in human melanoma and melanocyte cell lines.

BACKGROUND: Melanogenesis is a multistep process in which melanocytes produce melanin pigments within melanosomes. However, the roles played by the biological factors and pathways in this process are not yet fully understood. OBJECTIVE: To investigate the role of ATP-binding cassette subfamily B member 6 (ABCB6) in the regulation of melanogenesis in vitro. METHODS: Real-time PCR and western blotting were used to assess the knockdown efficiency of ABCB6 in MNT-1 and PIG1 stable cell lines. Cleavage by NaOH was used to determine melanin content, while the number of melanosomes was examined for each stage by transmission electron microscopy. Immunofluorescence microscopy was used to evaluate endogenous protein location. Differentially expressed genes were detected using RNA sequencing, and gene expression was assessed by quantitative real-time PCR. KEGG mapping was used for pathway enrichment analysis. Co-immunoprecipitation was used for protein-protein interactions analysis. RESULTS: We found that ABCB6 inhibition could impair melanocyte maturation and melanin production in human melanoma (MNT-1) and immortalized human melanocyte (PIG1) cell lines. Moreover, ABCB6 knockdown inhibited the protein expression of melanocyte inducing microphthalmia-associated transcription factor (MITF) and its three downstream melanogenic enzymes (TYR, TYRP1 and TYRP2). Mechanistically, we revealed that ABCB6 could interact with and modulate glycogen synthase kinase 3 beta (GSK3-ß) to exert its biological effect on melanogenesis. CONCLUSION: Our findings suggest that ABCB6 is a key regulator of melanogenesis via the GSK3-ß/ß-catenin signaling pathway. However, further in-depth studies are essential to uncover the relationship between ABCB6 and pigmentation disorders.

Effect of An Atmospheric Plasma Jet on the Differentiation of Melanoblast Progenitor.

OBJECTIVE: Melanoblasts are the cell source of regeneration for pigment restoration. The ability to differentiate into mature melanocytes is the essential feature of melanoblasts in depigmentation diseases. Cold atmospheric plasma is an ionized gas with near-room temperature and highly reactive species that has been shown to induce stem cell differentiation. The aim of the study was to explore the effect of cold atmospheric plasma on the differentiation of melanoblast progenitor cells. METHODS: In this study, melanoblasts were exposed to the plasma jet and the cell morphology was observed. The cell cycle and cell proliferation were detected. Furthermore, the cell immunofluorescence and the detection of melanin particle and nitric oxide were carried out to investigate the differentiation of melanoblast progenitor cells. RESULTS: Cells that were treated with the plasma had longer and more synaptic structures, and the G1 phase of cell cycle was prolonged in the treated group. More melanin synthesis-related proteins and melanin particles were produced after plasma treatment. Nitric oxide was one of the active components generated by the plasma jet, and the nitric oxide content in the cell culture medium of the treated group increased. CONCLUSION: These results indicate that an increase in nitric oxide production caused by a plasma jet can promote cell differentiation. The application of plasma provides an innovative strategy for the treatment of depigmentation diseases.

Prognostic Value of ALP and LDH in Periampullary Carcinoma Patients Undergoing Surgery.

OBJECTIVE: Conversion of normal cells to cancer cells is often accompanied by abnormal synthesis of serum enzymes. Both alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) have been reported to have prognostic value in a variety of malignancies. The aim of this study was to investigate the effect of preoperative serum ALP and LDH levels on the prognosis of patients with periampullary carcinoma who underwent pancreatoduodenectomy (PD). METHODS: According to the preoperative ALP or LDH values, 856 cancer patients receiving PD treatment from January 2001 to January 2019 were divided into high-ALP group and low-ALP group or high-LDH group and low-LDH group. Statistical analysis was carried out to study the differences between the high-ALP and low-ALP groups or the high-LDH and low-LDH groups. Furthermore, the possibility of preoperative ALP or LDH as prognostic factor of periampullary carcinoma was investigated. RESULTS: In both the high-ALP and the high-LDH groups, the prognosis of patients with periampullary carcinoma who underwent PD was worse than that of the low-ALP and low- LDH group. Even through risk factor analysis, it was found that preoperative ALP and LDH could be independent prognostic factor for patients with periampullary carcinoma who underwent PD. CONCLUSION: Preoperative ALP or LDH is an independent risk factor for periampullary carcinoma.

Methylcobalamin Protects Melanocytes from H2O2-Induced Oxidative Stress by Activating the Nrf2/HO-1 Pathway.

PURPOSE: Oxidative stress is considered a major determinant in the pathogenesis of vitiligo. Methylcobalamin (MeCbl) is an activated form of vitamin B12 that regulates inflammatory factors, counters oxidative stress, and reduces apoptosis in many disease models. However, the specific mechanism of MeCbl repigmentation against vitiligo is unknown. In this study, we explored the effect of MeCbl on melanocytes following hydrogen peroxide (H2O2)-induced oxidative stress. METHODS: We established an oxidative stress model using the immortalized human normal melanocyte cell line PIG1. We used a Cell Counting Kit-8 (CCK-8) to detect drug cytotoxicity, and we measured the melanin content of cells using the NaOH method. Intracellular oxidative damage was assessed by flow cytometry and antioxidant enzyme detection kits. In addition, we assessed the presence of apoptosis by flow cytometry and Western blots. We explored the underlying mechanisms of MeCbl during oxidative stress in melanocytes by analyzing the results of experiments based on real-time quantitative polymerase chain reaction (RT-qPCR), Western blotting, and laser scanning confocal immunofluorescence microscopy. Finally, we repeated the experiments after applying an inhibitor to block the Nrf2 pathway. RESULTS: We found that MeCbl treatment enhanced cell viability, increased melanin content, reduced intracellular reactive oxygen species (ROS) accumulation, increased the activities of antioxidant enzyme superoxide dismutase (SOD) and catalase (CAT), reduced melanocyte apoptosis, and up-regulated the expression of the Nrf2/HO-1 pathway. Moreover, the protective effects of MeCbl were significantly weakened after inhibiting the Nrf2/HO-1 pathway. CONCLUSION: Our results indicate that MeCbl attenuated the H2O2-induced oxidative stress in melanocytes by activating the Nrf2/HO-1 pathway, this suggests that MeCbl may be an effective treatment against vitiligo.

Identifying an lncRNA-Related ceRNA Network to Reveal Novel Targets for a Cutaneous Squamous Cell Carcinoma.

A cutaneous squamous cell carcinoma (cSCC) derived from keratinocytes is the second most common cause of non-melanoma skin cancer. The accumulation of the mutational burden of genes and cellular DNA damage caused by the risk factors (e.g., exposure to ultraviolet radiation) contribute to the aberrant proliferation of keratinocytes and the formation of a cSCC. A cSCC encompasses a spectrum of diseases that range from recursor actinic keratosis (AK) and squamous cell carcinoma (SCC) in situ (SCCIS) to invasive cSCCs and further metastatic SCCs. Emerging evidence has revealed that lncRNAs are involved in the biological process of a cSCC. According to the ceRNA regulatory theory, lncRNAs act as natural miRNA sponges and interact with miRNA response elements, thereby regulating the mRNA expression of their down-stream targets. This study was designed to search for the potential lncRNAs that may become potential therapeutic targets or biomarkers of a cSCC. Considering the spirit of the study to be adequately justified, we collected microarray-based datasets of 19 cSCC tissues and 12 normal skin samples from the GEO database (GSE42677 and GSE45164). After screening the differentially expressed genes via a limma package, we identified 24 differentially expressed lncRNAs (DElncRNAs) and 3221 differentially expressed mRNAs (DEmRNAs). The miRcode, miRTarBase, miRDB and TargetScan databases were used to predict miRNAs that could interact with DElncRNAs and DEmRNAs. A total of 137 miRNA-lncRNA and 221 miRNA-mRNA pairs were retained in the ceRNA network, consisting of 31 miRNAs, 11 DElncRNAs and 155 DEmRNAs. For the functional analysis, the top enriched biological process was enhancer sequence-specific DNA binding in Gene Ontology (GO) terms. The FoxO signaling pathway, autophagy and cellular senescence were the top enrichment terms based on a Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The combination of a STRING tool and Cytoscape software (plug-in MCODE) identified five core mRNAs and built a core mRNA-associated ceRNA network. The expression for five identified core mRNAs and their related nine lncRNAs was validated using the external dataset GSE7553. Finally, one lncRNA HLA-F-AS1 and three mRNAs named AGO4, E2F1 and CCND1 were validated with the same expression patterns. We speculate that lncRNA HLA-F-AS1 may sponge miR-17-5p or miR-20b-5p to regulate the expression of CCND1 and E2F1 in the cSCC. The present study may provide potential diagnostic and therapeutic targets for cSCC patients.

CD36- and obesity-associated granulosa cells dysfunction.

Emerging evidence indicates that obesity impairs granulosa cell (GC) function, but the underlying mechanisms remain unclear. Gene expression profiles in GC of non-polycystic ovary syndrome (PCOS) obese (NPO), PCOS obese (PO), PCOS normal weight (PN) and non-PCOS normal weight (NPN) patients were analysed by microarray analysis. Compared with the NPN group, there were 16, 545 and 416 differently expressed genes in the NPO, PO and PN groups respectively. CD36 was the only intersecting gene, with greater than two fold changes in expression between the NPO versus NPN and PO versus NPN comparisons, and was not present in the PN versus NPN comparison. In addition, levels of CD36 protein were higher in GC from obese than normal weight patients. Furthermore, CD36 overexpression in a GC line inhibited cell proliferation, as determined by the cell counting kit-8 (CCK8) test, promoted cell apoptosis, as determined by flow cytometry, and inhibited the secretion of oestradiol by depositing triglyceride in cells and increasing cellular lipid peroxide levels. These adverse effects were reduced by sulfo-N-succinimidyloleate, a specific inhibitor of CD36. Together, the findings of this study suggest that obesity with and without PCOS should be regarded as separate entities, and that CD36 overexpression in GC of obese patients is one of the mechanisms by which obesity impairs GC function.

Four novel mutations of ADAR1 in Chinese patients with dyschromatosis symmetrica hereditaria.

BACKGROUND: Novel mutations in adenosine deaminase acting on RNA 1 gene (ADAR1) are responsible for dyschromatosis symmetrica hereditaria (DSH). DSH patients display a mixture of hyperpigmented and hypopigmented macules on the dorsal aspects of the extremities, and freckle-like macules on the face. AIMS: To provide new evidence for further study of the etiopathogenisis of DSH. METHODS: Genomic DNA was extracted and used as a template for the polymerase chain reaction (PCR) amplification of all 15 coding exons as well as intron-exon boundaries of ADAR1. The PCR products were sequenced directly. RESULTS: We identified eight mutations of ADAR1 in four Chinese pedigrees and four individual patients, which were c.2722G>T, p.(Asp908Tyr), c.1657delA, p.(Ser553fs), c.2563_2564delCT, p.(Leu855fs), c.526T>G, p.(Leu176Val) as well as four previously reported mutations c. 3363_3364insT, p.(Lys1122fs), c. 2865_2866delGT, p.(Val955fs), c.1630C>T, p.(Arg544X), and c.2894C>T, p.(Pro965Leu). In silico analysis predicted that all the mutations reported were pathogenic. LIMITATIONS: We did not study how ADAR1 played its role in DSH. So, the exact pathogenic mechanism of ADAR1 in DSH patients wasn't clarified in this study. CONCLUSION: We found four novel ADAR1 mutations in this study. Our results enlarge the database on ADAR1 mutations associated with DSH.

Alternative Oxidase Promotes Biofilm Formation of Candida albicans.

This study was designed to analyze the effect of the mitochondrial respiratory pathways of Candida albicans (C. albicans) on the biofilm formation. The 2, 3-bis (2-methoxy- 4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay was used to measure the metabolic activities of biofilms formed by the C. albicans which were cultured in the presence of respiratory pathways inhibitors. The biofilms formed by the wide type (WT), GOA7-deleted (GOA31), GOAV-reconstituted (GOA32), AOXla-deleted (AOX1) and AOXlb-deleted (AOX2) C. albicans strains were examined by the XTT reduction assay and fluorescence microscopy. The expression of adhesion-related genes BCR1, ALS1, ALS3, ECE1 and HWP1 in the biofilms formed by the above five C. albicans strains was detected by real time polymerase chain reaction. It was found that the metabolic activity of biofilms formed by C. albicans was decreased in the presence of alternative oxidase inhibitor whereas it was increased in the presence of classical mitochondrial respiratory pathway complex HI or complex IV inhibitor. AOX1 strain produced scarce biofilms interspersed with few hyphal filaments. Moreover, no significant changes in the expression of BCR1 and ALS3 were observed in the AOX1 strain, but the expression of ALSI and ECE1 was down-regulated, and that of HWP1 was up-regulated. These results indicate that both AOX1 and AOX2 can promote the biofilm formation. However, AOXla primarily plays a regulatory role in biofilm formation in the absence of inducers where the promoting effect is mainly achieved by promoting mycelial formation.