Synergistic effect of Aloe vera flower and Aloe gel on cutaneous wound healing targeting MFAP4 and its associated signaling pathway: In-vitro study.

ETHNOPHARMACOLOGICAL RELEVANCE: Aloe vera (L.) Burm. f. (Liliaceae family) is a well-known traditional medicinal plant, that has been used to treat a variety of illnesses, for decades ranging from cancer to skin disorders including wounds. It has been included in the traditional and herbal healthcare systems of many cultures around the world, as well as the pharmacopeia of different countries. Several in vitro and in vivo studies have also confirmed its potential antioxidant, anti-inflammatory, and wound-healing activities, etc. in the consistency of its historical and traditional uses. However, most studies to date are based on the A. vera gel and latex including its wound-healing effects. Very few studies have been focused on its flower, and rarely with its effects on cutaneous wound healing and its molecular mechanism. AIM OF THE STUDY: To the best of our knowledge, this is the first study to report on the synergistic effect of the A. vera flower (AVF) and Aloe gel (PAG) on cutaneous wound-healing, as well as revealing its molecular mechanism targeting microfibril-associated glycoprotein 4 (MFAP4) and its associated signaling pathway. METHODS: To investigate the synergistic effect of A. vera flower and Aloe gel in cutaneous wound healing, cell viability, and cell migration, as well proliferation assay was performed. This was followed by quantitative real-time polymerase chain reaction and Western blot analyses in wounded conditions to check the effects of this mixture on protein and mRNA levels in normal human dermal fibroblast (NHDF) cells. Moreover, small interfering RNA (siRNA) -mediated knockdown of MFAP4 in NHDF cells was performed followed by migration assay and cell cycle analysis, to confirm its role in cutaneous wound healing. Additionally, HaCaT cells were included in this study to evaluate its migratory and anti-inflammatory effects. RESULTS: Based on our obtained results, the PAG and AVF mixture synergistically induced the proliferation, migration, and especially ECM formation of NHDF cells by enhancing the expression of MFAP4. Other extracellular components associated with MFAP4 signaling pathway, such as fibrillin, collagen, elastin, TGF ß, and α-SMA, also increased at both the protein and mRNA levels. Subsequently, this mixture initiated the phosphorylation of the extracellular signal-regulated kinase (ERK) and AKT signaling pathways, and the S-phase of the cell cycle was also slightly modified. Also, the mixture induced the migration of HaCaT cells along with the suppression of inflammatory cytokines. Moreover, the siRNA-mediated knockdown highlighted the crucial role of MFAP4 in cutaneous wound healing in NHDF cells. CONCLUSION: This study showed that the mixture of PAG and AVF has significant wound healing effects targeting MFAP4 and its associated signaling pathway. Additionally, MFAP4 was recognized as a new potential biomarker of wound healing, which can be confirmed by further in vivo studies.

Gold and silver plasmonic nanoprobes trace the positions of histone codes.

We visualized the distribution of heterochromatin in a single nucleus using plasmonic nanoparticle-conjugated H3K9me3 and H3K27me3 antibodies. Due to distance-dependent plasmonic coupling effects between nanoprobes, their scattering spectra shift to longer wavelengths as the distance between heterochromatin histone markers reduced during oncogene-induced senescence (OIS). These observations were supported by simulating scattering profiles based on considerations of particle numbers, interparticle distances, and the spatial arrangements of plasmonic nanoprobes. Using this plasmon-based colourimetric imaging, we estimated changes in distances between H3K9me3 and H3K27me3 during the formation of senescence-associated heterochromatin foci in OIS cells. We anticipate that the devised analytical technique combined with high-spatial imaging and spectral simulation will eventually lead to a new means of diagnosing and monitoring disease progression and cellular senescence. [BMB Reports 2022; 55(3): 111-112].

High-spatial and colourimetric imaging of histone modifications in single senescent cells using plasmonic nanoprobes.

Histones are closely related to the state of chromatin, and epigenetic modification of their tail results in regulation in cells. Therefore, developing various analytical tools to map the changes in position and distribution of histone modifications is helpful in studying underlying mechanisms. Herein, we propose a high-spatial and colourimetric imaging method using plasmonic nanoparticles as probes to visualize heterochromatin histone markers in a single nucleus. We visualized the reorganization between repressive histone markers, H3K9me3 and H3K27me3, caused by oncogene-induced senescence based on the scattering colours and spectral shift of plasmonic nanoprobes to longer wavelengths using their distance-dependent coupling effect. The measured scattering profiles were correlated with the computation results simulating the scattering spectra according to the arrangements and distances among the plasmonic nanoprobes. The plasmonic nanoprobe-based high-spatial hyperspectral imaging provides an advanced way to study the dynamics of histone modifications for predicting the progression of diseases or senescence.

Hypoxia-Driven HIF-1α Activation Reprograms Pre-Activated NK Cells towards Highly Potent Effector Phenotypes via ERK/STAT3 Pathways.

NK cells are the predominant innate lymphocyte subsets specialized to kill malignant tumor cells. In patients with advanced cancer, hypoxic stress shapes NK cells toward tumor-resistant and immunosuppressive phenotypes, hence a strategy to restore NK function is critical for successful tumor immunotherapy. Here, we present evidence that pre-activation and subsequent HIF-1α-dependent metabolic shift of NK cells from oxidative phosphorylation into glycolysis are keys to overcome hypoxia-mediated impairment in NK cell survival, proliferation, and tumor cytotoxicity. Specifically, exposing NK cells to 7-9 days of normoxic culture followed by a pO2 of 1.5% hypoxia led to a highly potent effector phenotype via HIF-1α stabilization and upregulation of its target genes, BNIP3, PDK1, VEGF, PKM2, and LDHA. RNA sequencing and network analyses revealed that concomitant reduction of p21/p53 apoptotic pathways along with upregulation of cell cycle-promoting genes, CCNE1, CDC6, CDC20, and downregulation of cell cycle-arrest genes, CDKN1A, GADD45A, and MDM2 were accountable for superior expansion of NK cells via ERK/STAT3 activation. Furthermore, HIF-1α-dependent upregulation of the NKp44 receptor in hypoxia-exposed NK cells resulted in increased killing against K562, CEM, and A375 tumor targets both in-vitro and in-vivo tumor clearance assays. Therefore, hypoxic exposure on pre-activated proliferating NK cells triggered HIF-1α-dependent pathways to initiate coordinated regulation of cell cycle, apoptosis, and cytotoxicity at the global gene transcription level. Our results uncover a previously unidentified role of HIF-1α-mediated metabolic reprogramming that can reverse impaired NK effector phenotypes to generate requisite numbers of functionally robust NK cells for adoptive cellular therapy for clinical evaluation.

The cancer driver genes IDH1/2, JARID1C/ KDM5C, and UTX/ KDM6A: crosstalk between histone demethylation and hypoxic reprogramming in cancer metabolism.

Recent studies on mutations in cancer genomes have distinguished driver mutations from passenger mutations, which occur as byproducts of cancer development. The cancer genome atlas (TCGA) project identified 299 genes and 24 pathways/biological processes that drive tumor progression (Cell 173: 371-385 e318, 2018). Of the 299 driver genes, 12 genes are involved in histones, histone methylation, and demethylation (Table 1). Among these 12 genes, those encoding the histone demethylases JARID1C/KDM5C and UTX/KDM6A were identified as cancer driver genes. Furthermore, gain-of-function mutations in genes encoding metabolic enzymes, such as isocitrate dehydrogenases (IDH)1/2, drive tumor progression by producing an oncometabolite, D-2-hydroxyglutarate (D-2HG), which is a competitive inhibitor of α-ketoglutarate, O2-dependent dioxygenases such as Jumonji domain-containing histone demethylases, and DNA demethylases. Studies on oncometabolites suggest that histone demethylases mediate metabolic changes in chromatin structure. We have reviewed the most recent findings regarding cancer-specific metabolic reprogramming and the tumor-suppressive roles of JARID1C/KDM5C and UTX/KDM6A. We have also discussed mutations in other isoforms such as the JARID1A, 1B, 1D of KDM5 subfamilies and the JMJD3/KDM6B of KDM6 subfamilies, which play opposing roles in tumor progression as oncogenes or tumor suppressors depending on the cancer cell type. Table 1 Cancer driver genes involved in epigenetics Pathways involved in epigenetics Driver genes Tumor suppressor/oncogene prediction (by 20/20+a) Approved name Activity Cancer typeb Other driver genes in this pathways Histone modification KDM6A tsg Lysine demethylase 6A, UTX H3K27me2/3 demethylase BLCA, HNSC, KIRP, LUSC, PAAD, PANCAN, PRAD PPP6C SETD2 tsg SET domain-containing 2 H3K36 methyl transferase KIRC, KIRP, LGG, LUAD, MESO, PANCAN Chromatin histone modifiers KDM5C tsg Lysine demethylase 5C, JARID1C H3K4me2/3 demethylase KIRC, PANCAN ARID5B, CREBBP, EP300, KANSL1, MEN1, NCOR1, NSD1, SIN3A, WHSC1, ZMYM3 KMT2A tsg Lysine methyltransferase 2A H3K4 methyl transferase PANCAN KMT2B tsg Lysine methyltransferase 2B H3K4 methyl transferase PANCAN, UCEC KMT2C tsg Lysine methyltransferase 2C H3K4 methyl transferase BLCA, BRCA, CESC, PANCAN, UCEC KMT2D tsg Lysine methyltransferase 2D H3K4 methyl transferase BLCA, CESC, DLBC, ESCA, HNSC, LUSC, PANCAN, PRAD Chromatin (other) H3F3A Possible oncogene H3 histone family member 3A, H3.3A PANCAN AJUBA, ASXL1, ASXL2, ATF7IP, BCOR, CHD3, CHD4, CHD8, CTCF, NIPBL, NPM1 H3F3C - H3 histone family member 3C, H3.5 PANCAN HIST1H1E Possible oncogene HIST1H1E, H1.4 DLBC Possible tsg HIST1H1E, H1.4 LIHC Metabolism IDH1 Oncogene Isocitrate dehydrogenase (NADP(+)) 1 NADP-dependent IDH, Cytosolic CHOL, GBM, LAML, LGG, LIHC, PANCAN, PRAD, SKCM - IDH2 Oncogene Isocitrate dehydrogenase (NADP(+)) 2 NADP-dependent IDH, Mitochondrial LAML, LGG, PANCAN Among the 299 driver genes mentioned by Bailey et al.47, only the epigenetics-related pathways have been sorted out a20/20+: Classifies genes as an oncogene, tumor suppressor gene, or as a nondriver gene using Random Forests, http://2020plus.readthedocs.org bBLCA (bladder urothelial carcinoma), BRCA (breast invasive carcinoma), CESC (cervical squamous cell carcinoma and endocervical adenocarcinoma), CHOL (cholangiocarcinoma), DLBC (lymphoid neoplasm diffuse large B-cell lymphoma), ESCA (esophageal carcinoma), GBM (glioblastoma multiforme), HNSC (head and neck squamous cell carcinoma), KIRC (kidney renal clear cell carcinoma), KIRP (kidney renal papillary cell carcinoma), LAML (acute myeloid leukemia), LGG (brain lower grade glioma), LIHC (liver hepatocellular carcinoma), LUAD (lung adenocarcinoma), LUSC (lung squamous cell carcinoma), MESO (mesothelioma), PAAD (pancreatic adenocarcinoma), PANCAN (Pan-cancer), PRAD (prostate adenocarcinoma), SKCM (skin cutaneous melanoma), THCA (thyroid carcinoma), UCEC (uterine corpus endometrial carcinoma).

Maintenance of the fistulous tract after recanalization via magnetic compression anastomosis in completely obstructed benign biliary stricture.

OBJECTIVE: This study compared the efficacy of a percutaneous transhepatic cholangioscopy (PTCS) catheter and a fully covered self-expandable metal stent (FCSEMS) for maintaining biliary tract patency after magnetic compression anastomosis (MCA). METHODS: This study included patients with completely obstructed benign biliary stricture (BBS), which was resolved by MCA and subsequent insertion of a PTCS catheter or FCSEMS. We compared the restenosis-free time after removal of the PTCS catheter or FCSEMS, and the rate of complications. RESULTS: A total of 49 patients were analyzed. The mean ages of the patients in these groups were 50.1 and 49.6 years, respectively. The predisposing conditions causing complete BBS were liver transplantation (n = 38), abdominal surgery (n = 10) and trauma (n = 1). The mean indwelling durations were 176 and 128 days in the PTCS catheter and FCSEMS groups, respectively. The mean follow-up duration after removal of the PTCS catheter and FCSEMS were 2259 and 680.5 days, respectively. Three patients in the PTCS group and three patients in the FCSEMS group experienced stricture relapse. The mean duration between recurrence and stent removal were 924 and 265 days, respectively, and the numbers of stricture-free days did not differ significantly between the two groups. The adverse event rate did not differ significantly between the PTCS and FCSEMS groups (50% vs. 24.2%, respectively). CONCLUSIONS: FCSEMSs have an efficacy and safety similar to those of PTCS catheters for maintaining biliary tract patency after MCA, but are more convenient for patients.

The association between Helicobacter pylori infection and the risk of advanced colorectal neoplasia may differ according to age and cigarette smoking.

BACKGROUND: The association between Helicobacter pylori infection and advanced colorectal neoplasia (ACN) remains controversial. This study aimed to clarify the association between H. pylori infection and ACN according to age groups. METHODS: We retrospectively analyzed the association between H. pylori infection and ACN in patients aged <50 and ≥50 years receiving a health checkup that included colonoscopy. Helicobacter pylori positivity was determined by the results of serum anti-H. pylori immunoglobulin G or rapid urease test, if the anti-H. pylori immunoglobulin G was in the borderline range. RESULTS: Among the 19 337 patients who were included, 56.2% and 3.4% were positive for H. pylori and ACN, respectively. Helicobacter pylori infection independently increased the risk of ACN in patients aged <50 years (odds ratio [OR], 1.602; 95% confidence intervals [CI], 1.194-2.150) but not in patients aged ≥50 years (OR, 1.046; 95% CI, 0.863-1.268). The positive association between H. pylori infection and ACN was affected by smoking history. When stratified by age and smoking history, H. pylori infection conferred an increased risk of ACN in patients aged <50 years with a history of smoking (OR, 1.926; 95% CI, 1.336-2.775) but not in the other 3 groups (3-way interaction test P = .023). Among patients aged <50 years with ACN, ACN in the left colon was found more frequently in patients with H. pylori infection and a history of smoking than in those without (69.3% vs 54.4%, respectively; P = .031). CONCLUSIONS: Helicobacter pylori infection confers an increased risk of ACN, but the association may differ according to age and smoking history.

Retention Esophagitis as a Significant Clinical Predictor of Progression to Esophageal Cancer in Achalasia.

BACKGROUND/AIMS: Chronic liquid and/or food stasis caused by retention esophagitis (RE) in achalasia is a notable endoscopic finding because of the presence of a thickened or whitish esophageal mucosa and histologically altered squamous hyperplasia. We aimed to identify the clinical features of RE associated with achalasia and to clarify the clinical definition of RE in achalasia as a precancerous lesion identified by analyzing biomarker expressions. METHODS: From 2006 to 2015, we retrospectively reviewed 37 patients with achalasia without previous treatment. Among them, 21 patients had diagnostic findings of RE (RE+) and 16 patients had no diagnostic findings of RE (RE-). Immunohistochemical staining of p53, p16, and Ki-67 was performed on the endoscopic biopsy tissues from the patients with achalasia and 10 control patients with non-obstructive dysphagia. RESULTS: The symptom duration and transit delay were significantly longer in the RE+ group than in the RE- group. We found particularly high p53 positivity rates in the RE+ group (p<0.001). The rate of p16 expression was also significantly higher in the RE+ group than in the other two groups (p=0.003). CONCLUSIONS: A high p53 expression rate was more frequently found in the RE+ group than in the other two groups. RE could be a meaningful clinical feature of achalasia for predicting esophageal carcinogenesis.

HBsAg-Negative, Anti-HBc-Negative Patients Still Have a Risk of Hepatitis B Virus-Related Hepatitis after Autologous Stem Cell Transplantation for Multiple Myeloma or Malignant Lymphoma.

PURPOSE: Although hepatitis B surface antigen (HBsAg)-negative, hepatitis B core antibody (anti-HBc)-negative patients are not considered to be at risk for hepatitis B virus (HBV)-related hepatitis, the actual risk remains to be elucidated. This study aimed to evaluate the risk of HBV-related hepatitis in HBsAg-negative, anti-HBc-negative patients receiving autologous stem cell transplantation (ASCT) for multiple myeloma (MM) or malignant lymphoma. MATERIALS AND METHODS: We retrospectively reviewed data from 271 HBsAg-negative patients (161 anti-HBc-negative and 110 anti-HBc-positive at the time of ASCT) who received ASCT for MM or lymphoma. The risk of HBV-related hepatitis was analyzed according to the presence of anti-HBc. HBV serology results at the time of ASCT were compared with those at the time of diagnosis of MM or lymphoma. RESULTS: Three patients (two anti-HBc-negative MMs and one anti-HBc-positive MM) developed HBV-related hepatitis after ASCT. The rate of HBV-related hepatitis did not differ among patients with or without anti-HBc status (p=0.843). HBV-related hepatitis more frequently occurred in MM patients than in lymphoma patients (p=0.041). Overall, 9.1% of patients (16.7% with MM and 5.4% with lymphoma) who were HBsAg-negative and anti-HBc-positive at the time of diagnosis had lost anti-HBc positivity during chemotherapy prior to ASCT. CONCLUSION: Our data suggest that HBsAg-negative, anti-HBc-negative patients at the time of ASCT for MM or lymphoma still might be at a risk for HBV-related hepatitis.

Distinct hypoxic regulation of preadipocyte factor-1 (Pref-1) in preadipocytes and mature adipocytes.

Preadipocyte factor-1 (Pref-1) is a secretory soluble protein, which exerts pleiotropic effects on maintenance of cancer stem cell characteristics and commitment of mesenchymal stem cell lineages by inhibiting adipogenesis. Observations that obesity renders the microenvironment of adipose tissues hypoxic and that hypoxia inhibits adipogenesis lead us to investigate whether hypoxia increases the expression of anti-adipogenic Pref-1 in preadipocytes, mature adipocytes, and adipose tissues from obese mouse. In 3T3-L1 preadipocytes, hypoxia induces Pref-1 by a hypoxia-inducible factor 1 (HIF-1)-dependent mechanism accompanied by increase in the levels of the active histone mark, acetylated H3K9/14 (H3K9/14Ac). Adipogenesis increased the levels of the heterochromatin histone mark, trimethylated H3K27 (H3K27me3), whereas it decreased the levels of H3K4me3 and H3K9/14Ac euchromatin marks of the mouse Pref-1 promoter. However, differently from preadipocytes, in mature adipocytes hypoxia failed to reverse the repressive epigenetic changes of Pref-1 promoter and to increase its expression. Short term (8weeks) high fat diet (HFD) increased HIF-1α protein in subcutaneous and epididymal adipose tissues, but did not increase Pref-1 expression. Unlike in 3T3-L1 preadipocytes, HIF-1α did not increase Pref-1 expression in adipose tissues in which mature adipocytes constitute the main population. Interestingly, long term (35weeks) HFD increased Pref-1 in serum but not in obese adipose tissues. This study suggests that Pref-1 is an endocrine factor which is synergistically increased by obesity and age.

Decitabine as a First-Line Treatment for Older Adults Newly Diagnosed with Acute Myeloid Leukemia.

PURPOSE: Decitabine, a DNA hypomethylating agent, was recently approved for use in Korea for older adults with acute myeloid leukemia (AML) who are not candidates for standard chemotherapy. This study aimed to evaluate the role of decitabine as a first-line treatment for older adults with AML. MATERIALS AND METHODS: Twenty-four patients with AML who received at least one course of decitabine (20 mg/m²/d intravenously for 5 days every 4 weeks) as a first-line therapy at Severance Hospital were evaluated retrospectively. RESULTS: The median age of the patients was 73.5 years. The longest follow-up duration was 502 days. A total of 113 cycles of treatment were given to 24 patients, and the median number of cycles was four (range, 1-14). Thirteen patients dropped out because of death, no or loss of response, patient refusal, or transfer to another hospital. Twenty-one (87.5%) and 12 (50%) patients completed the second and fourth cycles, respectively, and responses to treatment were evaluated in 17. A complete response (CR) or CR with incomplete blood-count recovery was achieved in six (35.3%) patients, and the estimated median overall survival was 502 days. Ten patients developed grade >2 hematologic or non-hematologic toxicities. In univariate analysis, bone marrow blasts, lactate dehydrogenase, serum ferritin level, and bone marrow iron were significantly associated with response to decitabine. CONCLUSION: Five-day decitabine treatment showed acceptable efficacy in older patients with AML who are unfit for conventional chemotherapy, with a CR rate 35.3% and about a median overall survival of 18 months.

Hypoxic reprograming of H3K27me3 and H3K4me3 at the INK4A locus.

Activation of Raf reduces the repressive histone mark H3K27me3 at the INK4a locus by inducing the H3K27me3 demethylase JMJD3. During hypoxia, the catalyitc activity of JMJD3 is reduced due to the limited availability of O2 as a substrate. In our study, we found that hypoxia prevented Raf-induced JMJD3 from demethylating H3K27me3 at the INK4a locus. Nonetheless, hypoxia did not prevent Raf signaling from inducing INK4a mRNA. Interestingly, we found that hypoxia strongly enhanced the active histone mark H3K4me3 at the INK4a locus by inhibiting the H3K4me3 demethylases JARID1A and JARID1B. Therefore, this study demonstrates that the O2 concentration in the microenvironment differentially affects the repressive methylation on K27 and the activating methylation on K4 at the INK4a locus by inhibiting the H3K27me3 and H3K4me3 demethylases.

The role of upfront autologous stem cell transplantation in high-risk younger patients with primary central nervous system lymphoma.

Upfront autologous stem cell transplantation (ASCT) has shown favourable outcome in patients with primary central nervous system lymphoma (PCNSL), but the role of risk-adapted upfront ASCT consolidation has not been evaluated in PCNSL. As PCNSL patients with the International Extranodal Lymphoma Study Group (IELSG) prognostic score ≥2 or those who did not achieve complete response after two courses of induction chemotherapy (non-CR1) have shown inferior outcomes, we retrospectively analysed the role of upfront ASCT in 66 high-risk (IELSG ≥2 and/or non-CR1) younger (age <65 years) immunocompetent PCNSL patients who achieved at least partial response after initial high-dose methotrexate-based chemotherapy. Nineteen patients who received upfront ASCT exhibited significantly better overall survival (OS, P = 0·021) and progression-free survival (PFS, P = 0·005) compared to 47 patients who did not. In univariate and multivariate analyses, upfront ASCT was associated with better OS (P = 0·037 and P = 0·025, respectively) and PFS (P = 0·009 and P = 0·007, respectively). In a propensity score-matched cohort (n = 36), patients who received upfront ASCT also showed better outcome (P = 0·037 for OS, P = 0·001 for PFS). Our results suggest that upfront ASCT consolidation might be especially beneficial for high-risk PCNSL patients.

A new prognostic model using absolute lymphocyte count in patients with primary central nervous system lymphoma.

PURPOSE: Primary central nervous system lymphoma (PCNSL) is an aggressive and rare extranodal non-Hodgkin lymphoma (NHL). Absolute lymphocyte count (ALC) has been suggested to have a prognostic value in several subtypes of NHL. We evaluated the prognostic significance of clinical factors, including ALC, in patients with PCNSL to develop a new prognostic model. METHODS: We analysed prognostic factors, including ALC, at diagnosis in 81 PCNSL patients receiving high-dose methotrexate-based therapy. RESULTS: The median ALC at diagnosis was 1210 × 10(6)/L (range, 210-3610), with lymphopenia (≤ 875 × 10(6)/L) being detected in 27 (33.3%) patients. In the multivariate analysis, Eastern Cooperative Oncology Group performance status (ECOG PS) >1 (hazard ratio [HR] 3.18, P=0.003), age >50 years (HR 4.23, P=0.012), and lymphopenia at diagnosis (HR 2.83, P=0.008) remained independent prognostic factors for low overall survival (OS). Lymphopenia was also a significant prognostic factor for progression-free survival (HR 3.17, P=0.001). By means of a new three-factor prognostic model using ECOG PS >1, age >50 years, and presence of lymphopenia, with 1 point assigned to each factor, we successfully classified the patients into three risk groups: low (0 and 1), intermediate (2), and high (3). The 5-year OS rates of the patients in the low-, intermediate-, and high-risk groups were 74.3%, 21.7%, and 12.5%, respectively (P<0.001). CONCLUSIONS: Low ALC is a useful indicator of poor prognosis in patients with PCNSL. The proposed three-factor model should be validated in large-scale studies.

Hypoxic repression of CYP7A1 through a HIF-1α- and SHP-independent mechanism.

Liver cells experience hypoxic stress when drug-metabolizing enzymes excessively consume O2 for hydroxylation. Hypoxic stress changes the transcription of several genes by activating a heterodimeric transcription factor called hypoxia-inducible factor- 1α/ß (HIF-1α/ß). We found that hypoxic stress (0.1% O2) decreased the expression of cytochrome P450 7A1 (CYP7A1), a rate-limiting enzyme involved in bile acid biosynthesis. Chenodeoxycholic acid (CDCA), a major component of bile acids, represses CYP7A1 by activating a transcriptional repressor named small heterodimer partner (SHP). We observed that hypoxia decreased the levels of both CDCA and SHP, suggesting that hypoxia repressed CYP7A1 without inducing SHP. The finding that overexpression of HIF-1α increased the activity of the CYP7A1 promoter suggested that hypoxia decreased the expression of CYP7A1 in a HIF-1-independent manner. Thus, the results of this study suggested that hypoxia decreased the activity of CYP7A1 by limiting its substrate O2, and by decreasing the transcription of CYP7A1. [BMB Reports 2016; 49(3): 173-178].

Improved quantification of protein in vaccines containing aluminum hydroxide by simple modification of the Lowry method.

Aluminum (Al) components in vaccines are known to act as adsorbents that interfere with accurate protein quantification by the Lowry method. Therefore, certain modifications based on the characteristics and compositions of the vaccine are required for determination of protein contents. We investigated the effects of an additional centrifugal separation and found that protein contents were overestimated by up to 238% without centrifugation through a collaborative study performed with hepatitis B vaccines containing Al. However, addition of a centrifugation step yielded protein concentrations that were similar to the actual values, with small coefficients of variation (CVs). Proficiency testing performed in 11 laboratories showed that four laboratories did not have satisfactory results for vaccines containing aluminum hydroxide, although all laboratories were proficient in protein analysis when samples did not contain aluminum hydroxide. Incomplete resuspension of aluminum hydroxide solution with alkaline copper solution was the major cause of insufficient proficiency in these laboratories.

The action of HIF-3α variants on HIF-2α-HIF-1ß heterodimer formation is directly probed in live cells.

Hypoxia-inducible factors (HIFs), consisting of α and ß subunits, activate various genes to adapt to low oxygen environments through their heterodimeric complex formation in the nucleus. While most of the studies have been extensively focused on the HIF-1α isoform, the effect of HIF-α isoforms on the complex formation between HIF-2α and HIF-1ß in live cells has not been reported in detail. To probe these interactions in a physiological condition, we established a fluorescence resonance energy transfer (FRET) assay by introducing fluorescent reporter proteins onto the N-termini of HIF-2α and HIF-1ß in live PC3 cells. After thorough validations of our FRET assay system, we showed that both HIF-1α and HIF-3α variants likely function as negative regulators on the heterodimer formation of HIF-2α with HIF-1ß in cells. We also characterized the localization and stabilization of HIF-3α variants and measured the interaction between HIF-3α variants and other HIF isoforms in live cells. In contrast to the previous results showing HIF-3α-mediated blockage of HIF-1α translocation, the presence of HIF-3α did not affect the localization of HIF-2α, suggesting distinct roles of HIF-3α in regulation of two HIF-α isoforms.

Chenodeoxycholic Acid Reduces Hypoxia Inducible Factor-1α Protein and Its Target Genes.

This study evaluated HIF-1α inhibitors under different hypoxic conditions, physiological hypoxia (5% O2) and severe hypoxia (0.1% O2). We found that chenodeoxy cholic acid (CDCA) reduced the amount of HIF-1α protein only under physiological hypoxia but not under severe hypoxia without decreasing its mRNA level. By using a proteasome inhibitor MG132 and a translation inhibitor cyclohexamide, we showed that CDCA reduced HIF-1α protein by decreasing its translation but not by enhancing its degradation. The following findings indicated that farnesoid X receptor (FXR), a CDCA receptor and its target gene, Small heterodimer partner (SHP) are not involved in this effect of CDCA. Distinctly from CDCA, MG132 prevented SHP and an exogenous FXR agonist, GW4064 from reducing HIF-1α protein. Furthermore a FXR antagonist, guggulsterone failed to prevent CDCA from decreasing HIF-1α protein. Furthermore, guggulsterone by itself reduced HIF-1α protein even in the presence of MG132. These findings suggested that CDCA and guggulsterone reduced the translation of HIF-1α in a mechanism which FXR and SHP are not involved. This study reveals novel therapeutic functions of traditional nontoxic drugs, CDCA and guggulsterone, as inhibitors of HIF-1α protein.

Beta-lapachone inhibits pathological retinal neovascularization in oxygen-induced retinopathy via regulation of HIF-1α.

Retinal neovascularization in retinopathy of prematurity (ROP) is the most common cause of blindness for children. Despite evidence that hypoxia inducible factor (HIF)-1α -VEGF axis is associated with the pathogenesis of ROP, the inhibitors of HIF-1α have not been established as a therapeutic target in the control of ROP pathophysiology. We investigated the hypothesis that degradation of HIF-1α as a master regulator of angiogenesis in hypoxic condition, using ß-lapachone, would confer protection against hypoxia-induced retinopathy without affecting physiological vascular development in mice with oxygen-induced retinopathy (OIR), an animal model of ROP. The effects of ß-lapachone were examined after intraocular injection in mice with OIR. Intraocular administration of ß-lapachone resulted in significant reduction in hypoxia-induced retinal neovascularization without retinal toxicity or perturbation of developmental retinal angiogenesis. Our results demonstrate that HIF-1α-mediated VEGF expression in OIR is associated with pathological neovascularization, not physiological angiogenesis. Thus, strategies blocking HIF-1α in the developing eye in the pathological hypoxia could serve as a novel therapeutic target for ROP.

Hypoxia-inducible factor-2α-dependent hypoxic induction of Wnt10b expression in adipogenic cells.

Adipocyte hyperplasia and hypertrophy in obesity can lead to many changes in adipose tissue, such as hypoxia, metabolic dysregulation, and enhanced secretion of cytokines. In this study, hypoxia increased the expression of Wnt10b in both human and mouse adipogenic cells, but not in hypoxia-inducible factor (HIF)-2α-deficient adipogenic cells. Chromatin immunoprecipitation analysis revealed that HIF-2α, but not HIF-1α, bound to the Wnt10b enhancer region as well as upstream of the Wnt1 gene, which is encoded by an antisense strand of the Wnt10b gene. Hypoxia-conditioned medium (H-CM) induced phosphorylation of lipoprotein-receptor-related protein 6 as well as ß-catenin-dependent gene expression in normoxic cells, which suggests that H-CM contains canonical Wnt signals. Furthermore, adipogenesis of both human mesenchymal stem cells and mouse preadipocytes was inhibited by H-CM even under normoxic conditions. These results suggest that O2 concentration gradients influence the formation of Wnt ligand gradients, which are involved in the regulation of pluripotency, cell proliferation, and cell differentiation.