The 5'-untranslated region regulates ATF5 mRNA stability via nonsense-mediated mRNA decay in response to environmental stress.

We previously reported that activating transcription factor 5 (ATF5) mRNA increases in response to amino acid limitation, and that this increase is dependent on mRNA stabilization. The ATF5 gene allows transcription of mRNAs with two alternative 5'-UTRs, 5'-UTRα and 5'-UTRß, derived from exon 1α and exon 1ß. 5'-UTRα contains the upstream open reading frames uORF1 and uORF2. Phosphorylation of eukaryotic initiation factor 2α during the integrated stress response had been previously shown to lead to bypassing of uORF2 translation and production of ATF5 protein. Translation of uORF2 is expected to result in translational termination at a position 125 nucleotides upstream of the exon junction, and this fits the criterion of a nonsense-mediated decay target mRNA. We investigated the potential role of 5'-UTRα in the control of mRNA stabilization, and found that 5'-UTRα reduced the stability of ATF5 mRNA. 5'-UTRα-regulated destabilization of mRNA was suppressed by knockdown of the nonsense-mediated decay factors Upf1 and Upf2. Mutation of the downstream AUG (uAUG2) rendered mRNA refractory to Upf1 and Upf2 knockdown. Moreover, 5'-UTRα-regulated down-regulation was hindered by amino acid limitation and tunicamycin treatment, and stress-induced phosphorylation of eukaryotic initiation factor 2α was involved in stabilization of ATF5 mRNA. These studies show that ATF5 mRNA is a naturally occurring normal mRNA target of nonsense-mediated decay, and provide evidence for linkage between stress-regulated translational regulation and the mRNA decay pathway. This linkage constitutes a mechanism that regulates expression of stress response genes.

Stress-induced translation of ATF5 mRNA is regulated by the 5'-untranslated region.

Activating transcription factor (ATF) 5 is a transcription factor belonging to the ATF/cAMP-response element-binding protein gene family. We previously reported that ATF5 mRNA expression increased in response to amino acid limitation. The ATF5 gene allows transcription of mRNAs with at least two alternative 5'-untranslated regions (5'-UTRs), 5'-UTRalpha and 5'-UTRbeta, derived from exon1alpha and exon1beta. 5'-UTRalpha contains highly conserved sequences, in which the upstream open reading frames (uORFs) uORF1 and uORF2 are found in many species. This study was designed to investigate the potential role of 5'-UTRs in translational control. These 5'-UTRs differentially determined translation efficiency from mRNA. The presence of 5'-UTRalpha or 5'-UTRbeta represses translation from the downstream ATF5 ORF. Moreover, 5'-UTRalpha-regulated translational repression is released by amino acid limitation or NaAsO(2) exposure. This release was not seen for 5'-UTRbeta. Mutation of uAUG2 in the uORF2 of 5'-UTRalpha restored the basal expression and abolished the positive regulation by amino acid limitation or arsenite exposure. We demonstrated that phosphorylation of eukaryotic initiation factor 2alpha was required for amino acid limitation-induced translational regulation of ATF5. Furthermore, arsenite exposure activated the exogenously expressed heme-regulated inhibitor kinase and induced the phosphorylation of eukaryotic initiation factor 2alpha in nonerythroid cells. These results suggest that translation of ATF5 is regulated by the alternative 5'-UTR region of its mRNA, and ATF5 may play a role in protecting cells from amino acid limitation or arsenite-induced oxidative stress.

Successful treatment of lymphadenosis benigna cutis with topical photodynamic therapy with delta-aminolevulinic acid.

BACKGROUND: Photodynamic therapy (PDT) using topical delta-aminolevulinic acid (ALA) has been used for nonmelanoma skin cancers, including malignant cutaneous T-cell lymphomas. Moreover, PDT has been tried for benign inflammatory or infectious skin lesions. OBJECTIVE: To evaluate the effects of ALA-PDT on skin lesions of lymphadenosis benigna cutis (LABC). PATIENTS AND METHODS: Two 16-year-old females with solitary and infiltrated nodules were treated 5 times with topical ALA-PDT. RESULTS: Both patients responded well and showed dramatic clinical and histopathological improvement without visible scars. CONCLUSION: The results confirm that topical ALA-PDT is an effective and safe modality for the treatment of LABC, and that such treatment may be cosmetically beneficial.

Sugar micro needles as transdermic drug delivery system.

We designed and fabricated an array of sugar micro needles of the length ranging from 150 micro m to 2 mm for transdermic delivery of drugs. Micro needles were molded out of maltose mixed with pharmaceutical material, being expected bio-degradable in the human skin. To test basic tolerance to the healthy human skin, a clinical experiment was carried out for 10 healthy adult volunteers. 500 microm-needles containing 5 wt% of ascorbate-2-glycoside were inserted into the skin of the forearm and snapped off to be left in the skin. They spontaneously dissolved by hydrolysis to release ascorbate in the epidermis and the dermis. No dermatological problems were observed in terms of the International Contact Dermatitis Research Group criteria. These observations indicate that the present system is a novel approach to achieve transdermic drug delivery.

Keratinocyte-specific modulation of type VII collagen gene expression by pro-inflammatory cytokines (tumor necrosis factor-alpha and interleukin-1beta).

Previous studies have shown that pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta up-regulate type VII collagen gene (COL7A1) expression in cultured dermal fibroblasts. The present study was designed to investigate the effects of TNF-alpha and IL-1beta on COL7A1 expression in epidermal keratinocytes. We demonstrated that both TNF-alpha and IL-1beta reduced COL7A1 expression in epidermal keratinocytes in an additive manner, whereas they increased COL7A1 expression in dermal fibroblasts. Thus, regulation of COL7A1 by pro-inflammatory cytokines is cell type specific. In particular, the inhibitory effects of TNF-alpha and IL-1beta occurred, at least in part, at the transcriptional level. Finally, we demonstrated that TNF-alpha and IL-1beta enhanced the TGF-beta-mediated up-regulation of COL7A1 expression in HaCaT keratinocytes, suggesting that the combination of TGF-beta and TNF-alpha or IL-1beta induces a signaling pathway that is completely different from that induced by either pro-inflammatory cytokine alone.