Hox code responsible for the pattering of the anterior vertebrae in zebrafish.

The vertebral column is a characteristic structure of vertebrates. Genetic studies in mice have shown that Hox-mediated patterning plays a key role in specifying discrete anatomical regions of the vertebral column. Expression pattern analyses in several vertebrate embryos provided correlative evidence that the anterior boundaries of Hox expression coincide with distinct anatomical vertebrae. However, because functional analyses have been limited to mice, it remains unclear which Hox genes actually function in vertebral patterning in other vertebrates. In this study, various zebrafish hox mutants were generated for loss-of-function phenotypic analysis to functionally decipher the Hox code responsible for the zebrafish anterior vertebrae between the occipital and thoracic vertebrae. We found that hox genes in HoxB- and HoxC-related clusters participate in regulating the morphology of the zebrafish anterior vertebrae. In addition, medaka hoxc6a was found to be responsible for anterior vertebral identity as in zebrafish. Based on phenotypic similarities with Hoxc6 knockout mice, our results suggest that the Hox patterning system, including at least Hoxc6, may have been functionally established in the vertebral patterning of the common ancestor of ray-finned and lobe-finned fishes.

Teleost Hox code defines regional identities competent for the formation of dorsal and anal fins.

The dorsal and anal fins can vary widely in position and length along the anterior-posterior axis in teleost fishes. However, the molecular mechanisms underlying the diversification of these fins remain unknown. Here, we used genetic approaches in zebrafish and medaka, in which the relative positions of the dorsal and anal fins are opposite, to demonstrate the crucial role of hox genes in the patterning of the teleost posterior body, including the dorsal and anal fins. By the CRISPR-Cas9-induced frameshift mutations and positional cloning of spontaneous dorsalfinless medaka, we show that various hox mutants exhibit the absence of dorsal or anal fins, or a stepwise posterior extension of these fins, with vertebral abnormalities. Our results indicate that multiple hox genes, primarily from hoxc-related clusters, encompass the regions responsible for the dorsal and anal fin formation along the anterior-posterior axis. These results further suggest that shifts in the anterior boundaries of hox expression which vary among fish species, lead to diversification in the position and size of the dorsal and anal fins, similar to how modulations in Hox expression can alter the number of anatomically distinct vertebrae in tetrapods. Furthermore, we show that hox genes responsible for dorsal fin formation are different between zebrafish and medaka. Our results suggest that a novel mechanism has occurred during teleost evolution, in which the gene network responsible for fin formation might have switched to the regulation downstream of other hox genes, leading to the remarkable diversity in the dorsal fin position.

An atlas of seven zebrafish hox cluster mutants provides insights into sub/neofunctionalization of vertebrate Hox clusters.

Vertebrate Hox clusters are comprised of multiple Hox genes that control morphology and developmental timing along multiple body axes. Although results of genetic analyses using Hox-knockout mice have been accumulating, genetic studies in other vertebrates have not been sufficient for functional comparisons of vertebrate Hox genes. In this study, we isolated all of the seven hox cluster loss-of-function alleles in zebrafish using the CRISPR-Cas9 system. Comprehensive analysis of the embryonic phenotype and X-ray micro-computed tomography scan analysis of adult fish revealed several species-specific functional contributions of homologous Hox clusters along the appendicular axis, whereas important shared general principles were also confirmed, as exemplified by serial anterior vertebral transformations along the main body axis, observed in fish for the first time. Our results provide insights into discrete sub/neofunctionalization of vertebrate Hox clusters after quadruplication of the ancient Hox cluster. This set of seven complete hox cluster loss-of-function alleles provide a formidable resource for future developmental genetic analysis of the Hox patterning system in zebrafish.

Fabrication of novel-shaped microneedles to overcome the disadvantages of solid microneedles for the transdermal delivery of insulin.

In this study, we fabricated two different microneedles (MNs) - semi-hollow and bird-bill - to overcome the limitations of solid and coated MNs, respectively. The two MN arrays were developed using a general injection molding process to obtain high-quality MNs with uniform shape. The semi-hollow and bird-bill MNs could penetrate the micropores of swine skin up to depths of 178.5 ± 27.6 µm and 232.1 ± 51.3 µm, respectively. When the semi-hollow MNs were used for the transdermal delivery of insulin in diabetic rats, it was observed that the blood glucose concentration (BGC) decreased remarkably within 30 min, and the desired effect of insulin was maintained for an additional 3 h after the removal of insulin from the skin surface. The bird-bill MN was able to load a coating gel at a maximum capacity of 3.20 ± 0.21 mg per MN array, and the BGC continued to decrease significantly after MN application for up to 2-6 h. In summary, we fabricated semi-hollow and bird-bill MN arrays using the injection molding method; these can be mass produced and are capable of effectively producing micro-holes in the stratum corneum. The two MN arrays could provide effective transdermal delivery of large-molecular-weight drugs such as insulin.

Efficacy of Botulinum Toxin B Injection for Raynaud's Phenomenon and Digital Ulcers in Patients with Systemic Sclerosis.

The efficacy and safety of botulinum toxin B (BTX-B) for treatment of Raynaud's phenomenon and digital ulcers in patients with systemic sclerosis was assessed. A total of 45 patients with systemic sclerosis who had Raynaud's phenomenon were blinded and divided randomly into 4 groups: a no-treatment control group, and 3 treatment groups, using 250, 1,000 or 2,000 international units (U) of BTX-B injections in the hand with more severe symptoms. Four weeks after injection, pain/numbness visual analogue scale scores and Raynaud's score in the groups treated with 1,000 and 2,000 U BTX-B were significantly lower than in the control group and the group treated with 250 U BTX-B. These beneficial effects were sustained until 16 weeks after the single injection. At 4 weeks after injection skin temperature recovery in the group treated with 2,000 U BTX-B was significantly improved. The numbers of digital ulcers in the groups treated with 1,000 and 2,000 U BTX-B were significantly lower than in the control group. In conclusion, 1,000 and 2,000 U BTX-B injections significantly suppressed the activity of Raynaud's phenomenon and digital ulcers in patients with SSc without serious adverse events.

Induction of the SHARP-2 mRNA level by insulin is mediated by multiple signaling pathways.

The rat enhancer of split- and hairy-related protein-2 (SHARP-2) is an insulin-inducible transcription factor which represses transcription of the rat phosphoenolpyruvate carboxykinase gene. In this study, a regulatory mechanism of the SHARP-2 mRNA level by insulin was analyzed. Insulin rapidly induced the level of SHARP-2 mRNA. This induction was blocked by inhibitors for phosphoinositide 3-kinase (PI 3-K), protein kinase C (PKC), and mammalian target of rapamycin (mTOR), actinomycin D, and cycloheximide. Whereas an adenovirus infection expressing a dominant negative form of atypical PKC lambda (aPKCλ) blocked the insulin-induction of the SHARP-2 mRNA level, insulin rapidly activated the mTOR. Insulin did not enhance transcriptional activity from a 3.7 kb upstream region of the rat SHARP-2 gene. Thus, we conclude that insulin induces the expression of the rat SHARP-2 gene at the transcription level via both a PI 3-K/aPKCλ- and a PI 3-K/mTOR- pathways and that protein synthesis is required for this induction.

Genome-wide association study of plasma resistin levels identified rs1423096 and rs10401670 as possible functional variants in the Japanese population.

Resistin is a cytokine inducing insulin resistance in mice. We previously identified single nucleotide polymorphisms (SNPs) at -420 (rs1862513) and -358 (rs3219175) located in the human resistin gene (RETN) promoter as strong determinants for circulating resistin in the Japanese population. The objective was to identify additional functional variants for circulating resistin. We conducted a genome-wide association study in 448 Japanese subjects. A peak association signal was found on chromosome 19 where RETN is located. The top-hit SNP was SNP -358 G>A, followed by rs1423096 C>T, SNP -420 C>G, and rs10401670 C>T (P = 5.39×10-47, 1.81×10-22, 2.09×10-16, and 9.25×10-15, respectively). Meta-analysis including another two independent general Japanese populations showed that circulating resistin was most strongly associated with SNP-358, followed by SNP-420, rs1423096, and rs10401670. Rs1423096 and rs10401670 were located in the 3'-region of RETN and were in strong linkage disequilibrium. Although these SNPs were also in linkage disequilibrium with the promoter SNPs, conditional and haplotype association analyses identified rs1423096 and rs10401670 as independent determinants for circulating resistin. Functionally, nuclear proteins specifically recognized T but not C at rs10401670 as evidenced by an electrophoretic mobility shift assay. The promoter activity of a luciferase reporter with T at either rs1423096 or rs10401670 was lower than that with C in THP-1 human monocytes. Therefore, rs1423096 and rs10401670, in addition to SNP-420 and SNP-358, were identified as possible functional variants affecting circulating resistin by the genome-wide search in the Japanese population.

Topical betamethasone butyrate propionate exacerbates pressure ulcers after cutaneous ischemia-reperfusion injury.

Ischaemia-reperfusion (I/R) is involved in the development of various organ diseases. There has been increasing evidence that cutaneous I/R injury is associated with the pathogenesis of pressure ulcers (PUs), especially at the early stage presenting as non-blanchable erythema. However, there is no evidence-based treatment for early-stage PUs. Our objective was to assess the effects of topical steroid on the development of PUs after cutaneous I/R injury in mice. Cutaneous I/R was performed by trapping the dorsal skin between two magnetic plates for 12 h, followed by plate removal. Topical application of betamethasone butyrate propionate (BBP) in I/R areas significantly increased the size of PUs after I/R. The number of thromboses was increased, and CD31(+) vessels were decreased in the I/R area treated with topical BBP. The number of oxidative stress-associated DNA-damaged cells and apoptotic cells in the I/R area was increased by topical BBP treatment. In addition, the mRNA level of NADPH oxidase 4 (Nox4), the essential enzyme that produces reactive oxygen species, was significantly increased and that of NF-E2-related factor 2 (Nrf2), a transcription factor that regulates the expression of antioxidant proteins, was inhibited in the I/R area treated by BBP. The number of CD68(+) macrophages and the level of transforming growth factor-beta in lesional skin were also decreased by BBP. These results suggest that a topical steroid might accelerate the formation of PUs induced by cutaneous I/R injury by aggravating oxidative stress-induced tissue damage. Topical steroids might not be recommended for the treatment of acute-phase decubitus ulcers.

Increased susceptibility to oxidative stress- and ultraviolet A-induced apoptosis in fibroblasts in atypical progeroid syndrome/atypical Werner syndrome with LMNA mutation.

Atypical progeroid syndrome (APS), including atypical Werner syndrome (AWS), is a disorder of premature ageing caused by mutation of the lamin A gene, the same causal gene involved in Hutchinson-Gilford syndrome (HGS). We previously reported the first Japanese case of APS/AWS with a LMNA mutation (p.D300N). Recently, it has been reported that UVA induced abnormal truncated form of lamin A, called progerin, as well as HGS-like abnormal nuclear structures in normal human fibroblasts, being more frequent in the elderly, suggesting that lamin A may be involved in the regulation of photoageing. The objective of this study was to elucidate the sensitivity to cell damage induced by oxidative stress or UVA in fibroblasts from APS/AWS patient. Using immunofluorescence staining and flow cytometry analysis, the amount of early apoptotic cells and degree of intra-cellular reactive oxygen species (ROS) generation were higher in H2 02 - or UVA-treated APS/AWS fibroblasts than in normal fibroblasts, suggesting that repeated UV exposure may induce premature ageing of the skin in APS/AWS patients and that protecting against sunlight is possibly important for delaying the emergence of APS/AWS symptoms. In addition, we demonstrated that H2 O2 -, or UVA-induced apoptosis and necrosis in normal and APS/AWS fibroblasts were enhanced by farnesyltransferase inhibitor (FTI) treatment, indicating that FTI might not be useful for treating our APS/AWS patient.

MFG-E8 regulates angiogenesis in cutaneous wound healing.

Our research group recently demonstrated that pericytes are major sources of the secreted glycoprotein and integrin ligand lactadherin (MFG-E8) in B16 melanoma tumors, and that MFG-E8 promotes angiogenesis via enhanced PDGF-PDGFRß signaling mediated by integrin-growth factor receptor crosstalk. However, sources of MFG-E8 and its possible roles in skin physiology are not well characterized. The objective of this study was to characterize the involvement of MFG-E8 in skin wound healing. In the dermis of normal murine and human skin, accumulations of MFG-E8 were found around CD31(+) blood vessels, and MFG-E8 colocalized with PDGFRß(+), αSMA(+), and NG2(+) pericytes. MFG-E8 protein and mRNA levels were elevated in the dermis during full-thickness wound healing in mice. MFG-E8 was diffusely present in granulation tissue and was localized around blood vessels. Wound healing was delayed in MFG-E8 knockout mice, compared with the wild type, and myofibroblast and vessel numbers in wound areas were significantly reduced in knockout mice. Inhibition of MFG-E8 production with siRNA attenuated the formation of capillary-like structures in vitro. Expression of MFG-E8 in fibrous human granulation tissue with scant blood vessels was less than that in granulation tissue with many blood vessels. These findings suggest that MFG-E8 promotes cutaneous wound healing by enhancing angiogenesis.

Pathogenesis of multiple lentigines in LEOPARD syndrome with PTPN11 gene mutation.

LEOPARD syndrome (LS) is an autosomal dominant condition with multiple anomalies, including multiple lentigines. LS is caused by mutations in PTPN11, encoding the protein tyrosine phosphatase, SHP-2. We report here 2 unrelated Japanese cases of LS with different PTPN11 mutations (p.Y279C and p.T468P). To elucidate the pathogenesis of multiple lentigines in LS, ultrastructural and immunohistochemical analyses of lentigines and non-lesional skin were performed. Numerous mature giant melanosomes in melanocytes and keratinocytes were observed in lentigines. In addition, the levels of expression of endothelin-1 (ET-1), phosphorylated Akt, mTOR and STAT3 in the epidermis in lentigines were significantly elevated compared with non-lesional skin. In in vitro assays, melanin synthesis in human melanoma cells expressing SHP-2 with LS-associated mutations was higher than in cells expressing normal SHP-2, suggesting that LS-associated SHP-2 mutations might enhance melanin synthesis in melanocytes, and that the activation of Akt/mTOR signalling may contribute to this process.

Role of endothelin-1/endothelin receptor signaling in fibrosis and calcification in nephrogenic systemic fibrosis.

Nephrogenic systemic fibrosis (NSF) is characterized by systemic fibrosis and abnormal calcification in patients with severe renal dysfunction. It is considered that gadolinium (Gd)-containing contrast agents used for magnetic resonance imaging trigger the development of NSF. However, the causative role of Gd and the mechanism of Gd-induced fibrosis and calcification in NSF are unknown. Recently, it has been known that endothelin-1 (ET-1)/ET receptor (ETR) signalling regulates fibrosis and calcification. The objective was to elucidate the role of ET-1/ETR signalling in Gd-induced fibrosis and calcification in NSF. First, we demonstrated that Gd enhanced proliferation and calcification of human adipose tissue-derived mesenchymal stem cells (hMSC) in vitro. Next, we examined the expression of ET-1 and ETR-A in hMSC using proliferation or calcification assay. ET-1 and ETR-A expression in hMSC treated with Gd were elevated. ET-1/ETR signalling inhibitor, bosentan, inhibited Gd-induced proliferation and calcification of hMSC. In addition, bosentan inhibited Gd-induced phosphorylation of ERK and Akt in hMSC. Plasma ET-1 levels of the patients were significantly higher than these of normal individuals and systemic sclerosis patients. In immunofluorescence staining, the expression of ETR-A in fibroblasts in dermal fibrosis lesion of NSF was increased. We conclude that Gd induces proliferation and calcification of hMSC via enhancement of ET-1/ETR signalling. Our results contribute to understand the pathogenesis of NSF.

Interaction analysis of a ladder-shaped polycyclic ether and model transmembrane peptides in lipid bilayers by using Förster resonance energy transfer and polarized attenuated total reflection infrared spectroscopy.

Ladder-shaped polycyclic ethers (LSPs) are predicted to interact with membrane proteins; however, the underlying mechanism has not been satisfactorily elucidated. It has been hypothesized that LSPs possess non-specific affinity to α-helical segments of transmembrane proteins. To verify this hypothesis, we constructed a model LSP interaction system in a lipid bilayer. We prepared 5 types of α-helical peptides and reconstituted them in liposomes. The reconstitution and orientation of these peptides in the liposomes were examined using polarized attenuated total reflection infrared (ATR-IR) spectroscopy and gel filtration. The results revealed that 4 peptides were retained in liposomes, and 3 of them formed stable transmembrane structures. The interaction between the LSP and the peptides was investigated using Förster resonance energy transfer (FRET). In the lipid bilayer, the LSP strongly recognized the peptides that possessed aligned hydrogen donating groups with leucine caps. We propose that this leucine-capped 16-amino acid sequence is a potential LPS binding motif.

Effects of inhaled ß­caryophyllene on vascular stiffness in smokers: A randomized, double­blind, placebo­controlled trial.

Approximately 1.14 billion smokers worldwide are at risk of developing tumors, cardiovascular diseases and respiratory diseases. Smoking cessation is the first choice of health care; however, the disease should be attenuated in individuals who never stop smoking, which escalates medical costs. Therefore, alternative options are needed to manage the social burden. The present study proposed an alternative method to prevent such diseases by inhalation of ß-caryophyllene (BCP). A placebo-targeted, dose-searching, double-blind, parallel-group comparative study was conducted on 19 subjects. The BCP intervention was performed using a flavor capsule inserted in a cigarette filter. The primary endpoint was the reducibility of brachial-ankle pulse wave velocity (baPWV). The secondary endpoints were confirmation of the bioavailability of BCP inhalation with cigarette smoke, confirmation of the effect of BCP inhalation on respiratory function, and association between respiratory function and blood concentration and baPWV reduction. The BCP concentration in the blood reached 4 ng/ml in the BCP 15% group 10 min after inhalation. The baPWV decreased in BCP-inhaling subjects whose initial baPWV was >1,300 cm/sec. The correlation analyses revealed that the higher the forced expiratory volume in 1 sec, the better the transition of baPWV. Inhaled BCP with cigarette smoke could reduce the baPWV and the risk of cardiovascular diseases in smokers. These findings indicated that with the introduction of BCP capsule-cigarettes in the future, smokers will be able to take care of their health, which may help reduce national medical costs. BCP microcapsules placed in cigarette wrapping paper may possibly reduce the risk of sidestream smoke and contribute to improved public health. This clinical research was retrospectively registered in the University Hospital Medical Information Network (UMIN)-Clinical Trials Registry with the following identifications: UMIN000048510 and UMIN000048512 on August 15, 2022.

A Pediatric Case of Cubitus Varus Deformity due to Olecranon Fracture.

We encountered a pediatric case of cubitus varus deformity with a sheared olecranon fracture in an 8-year-old boy who underwent corrective osteotomy without relevant medical history. The patient fell, resulting in a sheared olecranon fracture. He underwent a closed reduction and casting. As the displacement slightly increased within a week, we followed him without secondary reduction to expect remodeling. No remodeling occurred; corrective osteotomy was performed one-year post-injury for a marked cubitus varus deformity. At 2.5 years after corrective osteotomy, little difference existed in the carrying angle (CA) and varus angulation (VA) of the proximal ulna than that of the contralateral side, without pain or limited range of motion. The acceptable displacement range for pediatric forearm fractures is <1 cm shortening and 15° angular deformation in patients under 10 years old, and 10° angular deformation in older children. Here, the deformity of the ulna in the coronal plane did not remodel. Proximal forearm deformity can be accurately evaluated in flexion contracture elbows by measuring VA. Ulnar osteotomies are commonly performed on Monteggia fractures to reduce the radial head, and the osteotomy site is at the center of the deformity of the diaphysis. Corrective osteotomy for cubitus varus deformity after supracondylar humerus fracture improves function and cosmetic appearance, with good clinical results. In addition, it could prevent cubitus varus deformity from causing posterolateral rotatory instability. The coronal-plane deformity of the proximal ulnar was not expected to remodel. We recommended early accurate reduction and consideration of additional internal fixation for preventing re-displacement. Corrective osteotomy for cubitus varus deformity of the proximal ulna was an effective treatment.

Modified Boyes' procedure for the multiple finger extensor tendon ruptures in patients with rheumatoid arthritis: A report of two cases.

Multiple subcutaneous extensor tendon ruptures in more than the ulnar three fingers sometimes occur in patients with rheumatoid arthritis accompanied by wrist deformity. In these situations, the flexor digitorum superficialis tendon of the middle finger (the FDS3 tendon) and that of the ring finger (the FDS4 tendon) are used for the transferred tendon (modified Boyes' procedure). Here, we treated two patients with rheumatoid arthritis, whose extensor tendons of more than three fingers were ruptured, using the modified Boyes' procedure. Case 1 had ruptures in four fingers (index through little), and Case 2 had ruptures in three fingers (middle through little). The FDS3 and FDS4 tendons were passed subcutaneously around the radial side of the wrist to the extensor sides and interlaced with the distal stump of the ruptured tendons. Switching of the finger movement was achieved smoothly in both cases. The post-operative evaluation showed an extension lag of -15° for the index finger 0° for the middle through the little fingers in Case 1, and 0° for the middle finger and -5° for the ring and little fingers in Case 2. The average post-operative extension lag was -3.5°. However, median nerve palsy occurred in both cases, and it gradually recovered. Stretching of the nerve by the correction of the wrist deformity and increased pressure in the carpal tunnel were supposed to be causes of this palsy. Modified Boyes' procedure is a useful method for more than three ulnar finger extensor tendon ruptures; however, post-operative median nerve palsy should be considered.

Analysis of regulatory mechanisms of an insulin-inducible SHARP-2 gene by (S)-Equol.

Small compounds that activate the insulin-dependent signaling pathway have potential therapeutic applications in controlling type 2 diabetes mellitus. The rat enhancer of split- and hairy-related protein-2 (SHARP-2) is an insulin-inducible transcription factor that decreases expression of the phosphoenolpyruvate carboxykinase gene, a gluconeogenic enzyme gene. In this study, we screened for soybean isoflavones that can induce the rat SHARP-2 gene expression and analyzed their mechanism(s). Genistein and (S)-Equol, a metabolite of daidzein, induced rat SHARP-2 gene expression in H4IIE rat hepatoma cells. The (S)-Equol induction was mediated by both the phosphoinositide 3-kinase- and protein kinase C (PKC)-pathways. When a dominant negative form of atypical PKC lambda (aPKCλ) was expressed, the induction of SHARP-2 mRNA level by (S)-Equol was inhibited. In addition, Western blot analyses showed that (S)-Equol rapidly activated both aPKCλ and classical PKC alpha. Furthermore, the (S)-Equol induction was inhibited by treatment with a RNA polymerase inhibitor or a protein synthesis inhibitor. Finally, a reporter gene assay revealed that the transcriptional stimulation by (S)-Equol was mediated by nucleotide sequences located between -4687 and -4133 of the rat SHARP-2 gene. Thus, we conclude that (S)-Equol is an useful dietary supplement to control type 2 diabetes mellitus.

Inhaled volatile ß-caryophyllene is incorporated into the aortic wall and attenuates nicotine-induced aorta degeneration via a CB2 receptor-dependent pathway.

ß-caryophyllene (BCP) is a volatile bicyclic sesquiterpenoid found in essential oils obtained from several spices such as black pepper, oregano, basil, rosemary, cinnamon, and clove. BCP is a selective agonist of cannabinoid receptor 2 (CB2 receptor), and orally administered BCP exhibits various biological activities, including anti-inflammatory, antioxidant, and neuroprotective effects. However, it is still unclear how volatile BCP affects living organisms. We previously reported that inhaled BCP is transferred to sera and organs in mice; additionally, metabolomic analysis revealed inhaled BCP affect the dynamics of metabolites in the livers of mice. These data suggest that inhaled BCP may affect several biological activities by stimulating biological systems. In this study, we evaluated the effects of BCP inhalation on nicotine-induced degeneration of the aortic wall. In the group of mice which inhaled volatile BCP, nicotine-induced increases in elastic fiber degradation and matrix metalloproteinase-2 (MMP-2)-positive areas were attenuated. In addition, BCP improved the nicotine-induced stiffness of aortae and vulnerability to aortic rupture. In cultured aortae, the suppressive effects of BCP were inhibited by the CB2 receptor inhibitor AM630. These results suggest that inhaled BCP is incorporated into the aortic wall and prevents nicotine-induced degeneration of the aorta via a CB2 receptor-dependent pathway.

Retinoic acid stimulates transcription of the rat SHARP-2 gene via multiple pathways.

Members of the enhancer of split- and hairy-related protein (SHARP) family, SHARP-1 and SHARP-2, are basic helix-loop-helix transcriptional repressors and belong to the clock genes. In this study, an effect of retinoic acid (RA) on the SHARP family gene expression in the differentiated cells was examined. RA rapidly and temporarily induced the SHARP-2 mRNA expression in hepatic H4IIE cells. Then, whether the SHARP-2 mRNA expression is altered by dexamethasone (Dex), insulin, and the combination of RA and Dex or RA and insulin was examined. Dex had different effects on the expression of SHARP-2 mRNA in the presence or absence of RA. Then, the molecular mechanisms were investigated using inhibitors of various signaling molecules. The RA-induction of SHARP-2 mRNA level was mainly inhibited by LY294002, staurosporine, and actinomycin D, respectively. Finally, whether RA acts on the transcriptional regulatory region of the SHARP-2 gene was analysed using luciferase reporter gene assay. At least two RA-responsive regions were mapped at the nucleotide sequences between -3,700 and -1,600 of the SHARP-2 gene. In addition, this effect was dependent on the RA receptor and retinoid X receptor. Thus, we conclude that RA stimulated transcription of the SHARP-2 gene via multiple pathways.