Hyaluronan exists in the normal stratum corneum

Hyaluronan is well known to exist as a water-sorbed macromolecule in the extracellular matrix. We here examined whether hyaluronan exists in the normal stratum corneum. High performance liquid chromatography was used to quantify hyaluronan content in the stratum corneum, epidermis (including stratum corneum), and dermis of mice, with the resulting dry weights being 22.3 +/- 2.9, 15.1 +/- 1.5, and 738.6 +/- 31.6 microg per g, respectively. Normal mouse skin was then labeled with [3H]-glucosamine in an organ culture, and accumulation of [3H]-labeled hyaluronan and its molecular mass were determined separately for the stratum corneum, epidermis, and dermis. In the stratum corneum, [3H]-labeled hyaluronan was accumulated linearly over the 3-d culture period. After the 3-d culture period, the epidermis synthesized twice the amount (expressed as dpm per mg dry weight) of [3H]-labeled hyaluronan as the dermis, whereas the stratum corneum and dermis showed nearly the same content of [3H]-labeled hyaluronan. The molecular mass of [3H]-labeled hyaluronan was highest (>1.0 x 106) in the dermis and clearly lower (<6.0 x 104) in the stratum corneum. Based on these results, we here confirm that hyaluronan is supplied from keratinocytes beneath the stratum corneum layer, and is present in the normal stratum corneum. We speculate that hyaluronan may play a role in moisturizing the stratum corneum and/or regulating its mechanical properties.

Putative hyaluronan synthase mRNA are expressed in mouse skin and TGF-beta upregulates their expression in cultured human skin cells

We examined in situ expression of putative hyaluronan synthase genes, Has1 and Has2, and effects of transforming growth factor-beta on their expression. In situ mRNA hybridization showed that mouse skin expressed both Has1 and Has2 mRNA in dermis and epidermis. In dermis, the number of cells expressing the Has1 mRNA was less than that of the Has2 mRNA, and in epidermis, some strong signals from both mRNA were seen in stratum granulosum. Northern blot analysis showed that cultured human skin fibroblasts expressed Has1 mRNA of 2.4 kb and Has2 mRNA of 3.2 and 4.8 kb, whereas human keratinocytes expressed Has1 mRNA of 4.8 but not 2.4 kb and a trace of Has2 mRNA. When the cultures were stimulated with transforming growth factor-beta, both Has1 and Has2 mRNA were upregulated in fibroblasts, and only Has1 mRNA of 2.4 but not 4.8 kb was induced in keratinocytes. The maximal amount of the upregulated Has1 mRNA in keratinocytes at 2 h after stimulation decreased time-dependently to the nonstimulated level at 18 h, although the stimulation for 18 h of fibroblasts was effective on the expression of both Has mRNA. Differences in expression pattern of Has and Has2 mRNA in mouse skin and a higher response of fibroblasts to transforming growth factor-beta suggest that Has1 and Has2 genes are regulated independently and synthesized hyaluronan may have a different function in epidermis and dermis.

Synergistic Effect of N-Acetylglucosamine and Retinoids on Hyaluronan Production in Human Keratinocytes

Hyaluronan (HA) is well known to reside in the extracellular matrix as a water-sorbed macromolecule. The aims of this study were twofold: to investigate the regulation of HA synthesis in keratinocytes, and to develop a method to modulate this regulatory process. We found that N-acetylglucosamine (NAG) increased the production of HA by cultured keratinocytes dose dependently, but had no effect on the production by skin fibroblasts. The effect of NAG in keratinocytes was found to be specific for HA production, as there was no change in sulfated glycosaminoglycan formation. The copresence of NAG with either of two retinoids, retinoic acid (RA) or retinol, exerted a synergistic effect on HA production. To investigate whether human HA synthase (HAS) genes were regulated by NAG or retinoids, total RNA extracted from cells treated with these agents was subjected to Northern blot analysis. We observed that RA and retinol markedly induced the expression of HA synthase-3 (HAS3) mRNA. Moreover, beta-carotene, a provitamin A, influenced HA production and HAS3 gene expression in a manner similar to the retinoids. Conversely, NAG had no effect on the expression of HAS3 transcripts. Pretreatment of cells with RA stimulated the activity of membrane-associated HAS, whereas pretreatment with NAG did not. These results suggest that HA production is regulated by at least two pathways: one involving the regulation of HAS gene expression, and the other independent of such a regulatory effect. Taken together, our findings suggest that NAG is a new modulator of HA synthesis.

Reduction of hyaluronan and increased expression of HYBID (alias CEMIP and KIAA1199) correlate with clinical symptoms in photoaged skin

BACKGROUND

Hyaluronan (HA) metabolism in skin fibroblasts is mediated by HYBID (hyaluronan binding protein involved in hyaluronan depolymerization, alias CEMIP and KIAA1199) and the HA synthases HAS1 and HAS2. However, photoageing-dependent changes in HA and their molecular mechanisms, and the relationship between HA metabolism and clinical symptoms in photoaged skin remain elusive.

OBJECTIVES

We examined the amount, size and tissue distribution of HA and expression levels of HYBID, HAS1 and HAS2 in photoaged skin, and analysed their relationship with the degree of photoageing.

METHODS

Photoageing-dependent changes of HA were investigated by studying skin biopsies isolated from photoprotected and photoexposed areas of the same donors, and the relationships between HA and photoageing symptoms such as skin wrinkling and sagging were examined.

RESULTS

Skin biopsy specimens showed that the amount and size of HA are decreased in photoexposed skin compared with photoprotected skin, and this was accompanied by increased expression of HYBID and decreased expression of HAS1 and HAS2. Histologically, HA staining in the papillary dermis was decreased in photoexposed skin, showing reverse correlation with HYBID expression. HYBID expression in the photoexposed skin directly correlated with skin roughness and sagging parameters, and the reduced HA staining in the papillary dermis in the photoexposed skin positively correlated with these symptoms.

CONCLUSIONS

These data demonstrate that imbalance between HYBID-mediated HA degradation and HAS-mediated HA synthesis may contribute to enhanced HA catabolism in photoaged skin, and suggest that HYBID-mediated HA reduction in the papillary dermis is related to skin wrinkling and sagging of photoaged skin.

Relationship of hyaluronan and HYBID (KIAA1199) expression with roughness parameters of photoaged skin in Caucasian women

BACKGROUND

Hyaluronan (HA) is an important constituent of extracellular matrix (ECM) in the skin, and HA degradation mediated by HYBID (KIAA1199) is suggested to be implicated in facial skin wrinkling in Japanese women. Ethnic difference in skin wrinkle formation is known between Caucasian and Japanese women, but no information is available for the relations of HA and HYBID expression levels with skin wrinkling in Caucasian women.

METHODS

The skin surface roughness at the eye corner of the Caucasian female subjects was measured, and the skin specimens biopsied from the same areas were subjected to microarray gene analysis, HA staining, and immunohistochemistry for HYBID.

RESULTS

Among the ECM genes and those related to ECM metabolism, only HYBID expression levels positively correlated with the skin roughness parameters. When the skin sample groups with high expression of HYBID or low expression of HYBID were compared, the HA staining intensity and the ratio of HYBID-immunoreactive cells to total cells in the superficial dermis were significantly reduced and increased in the high-HYBID-expression group compared with the low-HYBID-expression group, respectively.

CONCLUSION

Our data suggest that like Japanese women, HYBID-mediated reduction of HA in the superficial dermis is involved in the formation of wrinkles in Caucasian women.

Inhibitory effects of Sanguisorba officinalis root extract on HYBID (KIAA1199)-mediated hyaluronan degradation and skin wrinkling

OBJECTIVES

Hyaluronan (HA), an important constituent of extracellular matrix in the skin, has many biological activities such as hydration that contributes to firmness and bounciness of the skin. We have reported that reduction in HA in the papillary dermis and over-expression of HYBID (HYaluronan Binding protein Involved in hyaluronan Depolymerization, alias KIAA1199 or CEMIP), a key molecule for HA degradation in skin fibroblasts, are implicated in facial skin wrinkling in Japanese and Caucasian women. However, little or no information is available for substances which inhibit the HYBID-mediated HA degradation.

METHODS

Inhibition of Sanguisorba officinalis root extract and ziyuglycoside I, one of the components of Sanguisorba officinalis root extract, to the HYBID-mediated HA degradation was assessed by size-exclusion chromatography of HA depolymerized by stable transfectants of HYBID in HEK293 cells (HYBID/HEK293 cells) or normal human skin fibroblasts (Detroit 551 cells and NHDF-Ad cells). The HYBID mRNA and protein expression was examined by quantitative real-time PCR and immunoblotting in the skin fibroblasts treated with Sanguisorba officinalis root extract, and size distribution of newly produced HA was evaluated by preparing metabolically radiolabelled HA. A double-blind, randomized and placebo-controlled study was carried out in the 21 healthy Japanese women, who were topically treated with the formulation containing Sanguisorba officinalis root extract or the placebo on each side of the face including crow's foot area.

RESULTS

Sanguisorba officinalis root extract, but not ziyuglycoside I, abolished HYBID-mediated HA degradation by HYBID/HEK293 cells. Sanguisorba officinalis root extract also inhibited HYBID-mediated HA degradation in skin fibroblasts by down-regulating HYBID mRNA and protein expression. Although control untreated skin fibroblasts produced polydispersed HA, the cells treated with Sanguisorba officinalis root extract produced only high-molecular-weight HA. Treatment with Sanguisorba officinalis root extract-formulated lotion significantly improved skin elasticity, and reduced skin wrinkling scores at the outer eye corner compared with the placebo formulation.

CONCLUSION

Sanguisorba officinalis root extract showed an anti-HYBID-mediated HA degradation activity and anti-wrinkle activity on human facial skin, which is accompanied by the improvement in elasticity. Our study provides the possibility of a new strategy to inhibit HYBID-mediated HA degradation for anti-wrinkle care.

N-Methyl-L-serine stimulates hyaluronan production in human skin fibroblasts

We examined the effects of N-methyl-L-serine (NMS), an amino acid derivative, on hyaluronan (HA) synthesis in human skin fibroblasts. NMS (1-10 mM), but not L-serine, stimulated the incorporation of [(3)H]glucosamine into HA dose-dependently, with a maximum stimulation of 1.5-fold compared to the control. The effect of NMS was specific for HA production, because there was no change in sulfated glycosaminoglycan formation. Neither the N-methyl derivatives of L-glycine or L-alanine, nor N-methyl-D-serine, could stimulate HA synthesis, indicating that the beta-hydroxyl group and the L-configuration were essential for the activity. Gel filtration of the products showed that NMS stimulated the production of high-molecular-mass HA (>10(6) D) without affecting the production of low-molecular-mass HA. NMS required 24 h to stimulate HA production, and when fibroblasts were pretreated for 10-24 h with NMS (1-10 mM), membrane-associated HA synthase activity was increased dose-dependently. Thus, a second messenger is likely to be involved in the stimulation of HA production by NMS.

Expression landscapes in non-small cell lung cancer shaped by the thyroid transcription factor 1

TTF-1-expressing non-small cell lung cancer (NSCLC) is one of the most prevalent lung cancer types worldwide. However, theparadoxical activity of TTF-1 in both lung carcinogenesis and tumor suppression is believed to be context-dependentwhich calls for a deeper understanding about the pathological expression of TTF-1. In addition, the expression circuitry of TTF-1-target genes in NSCLC has not been well examined which necessitates to revisit the involvement of TTF-1- in a multitude of oncologic pathways. We used RNA-seq and clinical data of patients from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx), including ChIP-seq data from different NSCLC cell lines, and mapped the proteome of NSCLC tumor. Our analysis showed significant variability in TTF-1 expression among NSCLC,and further clarified that this variability is orchestrated at the transcriptional level. We also found that high TTF-1 expression could negatively influence the survival outcomes of stage 1 LUAD which may be attributed to growth factor receptor-driven activation of mitogenic and angiogenic pathways. Mechanistically, TTF-1 may also control the genes associated with pathways involved in acquired TKI drug resistance or response to immune checkpoint inhibitors. Lastly, proteome-based biomarker discovery in stage 1 LUAD showed that TTF-1 positivity is potentially associated with the upregulation of several oncogenes which includes interferon proteins, MUC1, STAT3, and EIF2AK2. Collectively, this study highlights the potential involvement of TTF-1 in cell proliferation, immune evasion, and angiogenesis in early-stage NSCLC.

NKX2‑1 copy number alterations are associated with oncogenic, immunological and prognostic remodeling in non‑small cell lung cancer

NK2 homeobox 1 (NKX2-1) copy number alterations (CNAs) are frequently observed in lung cancer. However, little is known about the complete landscape of focal alterations in NKX2-1 copy number (CN), their clinical significance and their therapeutic implications in non-small cell lung cancer (NSCLC). The correlations between NKX2-1 expression and EGFR driver mutations and programmed death ligand 1 (PD-L1) co-expression were studied using immunohistochemistry and PCR from the tumors of recruited Filipino patients (n=45). Clinical features of NSCLC with NKX2-1 CNAs were resolved at the tumor and clonal levels using the molecular profiles of patients with lung adenocarcinoma and lung squamous cell carcinoma from The Cancer Genome Atlas (n=1,130), and deconvoluted single-cell RNA-seq data from the Bivona project (n=1,654), respectively. Despite a significant and positive correlation between expression and CN (r=0.264; P<0.001), NKX2-1 CNAs exerted a stronger influence on the combined EGFR and PD-L1 status of NSCLC tumors than expression. NKX2-1 CN gain was prognostic of favorable survival (P=0.018) and a better response to targeted therapy. NKX2-1 CN loss predicted a worse survival (P=0.041). Mutational architecture in the Y-chromosome differentiated the two prognostic groups. There were 19,941 synonymous mutations and 1,408 genome-wide CN perturbations associated with NKX2-1 CNAs. Tumors with NKX2-1 CN gain expressed lymphocyte markers more heterogeneously than those with CN loss. Higher expression of tumor-infiltrating lymphocyte gene signatures in CN gain was prognostic of longer disease-free survival (P=0.005). Tumors with NKX2-1 CN gain had higher B-cell (P<0.001) and total T-cell estimates (P=0.003). NKX2-1 CN loss was associated with immunologically colder tumors due to higher M2 macrophage infiltrates (P=0.011) and higher expression of immune checkpoint proteins, CD274 (P=0.025), VTCN1 (P<0.001) and LGALS9 (P=0.002). In conclusion, NKX2-1 CNAs are associated with tumors that exhibit clinically diverse characteristics, and with unique oncogenic, immunological and prognostic signatures.

The differential prognostic implications of PD-L1 expression in the outcomes of Filipinos with EGFR-mutant NSCLC treated with tyrosine kinase inhibitors

Background

The tumor immune microenvironment influences tumor evolution in non-small cell lung cancer (NSCLC). Yet, the prognostic value of programmed death-ligand 1 (PD-L1) in epidermal growth factor receptor (EGFR)-mutant NSCLC remains controversial. Additionally, prognostic studies in Filipinos with EGFR-mutant NSCLC remain unexplored to this day.

Methods

We prospectively studied the outcomes of EGFR-mutant NSCLC in Filipino cohort, and retrospectively verified the survival trend using The Cancer Genome Atlas (TCGA) cohort. Kaplan-Meier method and generalized linear regression were used to assess survival. Expression and DNA methylation of cluster of differentiation 274 (CD274, gene that codes for PD-L1) were examined from TCGA tumor profiles. Pearson's correlation was used to correlate PD-L1 expression with outcomes associated with occurrence of EGFR mutations, tyrosine kinase inhibitor (TKI) types, and programmed cell death protein 1 (PD-1) expression. Proteome network analysis was used to examine the correlation between drug resistance and PD-L1.

Results

PD-L1 positivity was associated with significantly longer progression-free survival (PFS; P=0.0096) but had a significantly contrasting influence in the overall survival (OS; P=0.0011). PD-L1 positivity (in both protein and RNA) was associated with longer median OS (mOS) in exon21 L858R, whereas, negativity was associated with longer mOS in exon19 deletion (exon19del). Stratification (high, low, negative) of PD-L1 expression lacked significant prognostic value (all P>0.05). PD-L1/CD274 expression (P<0.05) and DNA methylation (P<0.001) vary significantly among NSCLC subtypes and in different disease stages. Erlotinib treatment produced the longest median progression-free survival (mPFS; 874 days) relative to other EGFR-TKIs (137-311 days). PD-L1 lacked a significant correlation with EGFR-TKIs. Consistent with the immune-regulation activities of PD-1, higher expression leads to relatively shorter mOS. PD-1 correlated positively with PD-L1 expression and occurrence of exon21 L858R.

Conclusions

PD-L1 differentially influenced the outcomes of Filipinos with EGFR-mutant NSCLC. NSCLC subtypes, disease stage, and PD-1 expression may impact the collective outcomes associated with PD-L1 and EGFR-sensitizing mutations.