[Successful treatment of acute promyelocytic leukemia with all-trans retinoic acid on hemodialysis for acute renal failure].

All-trans retinoic acid (ATRA) is used as standard induction therapy for acute promyelocytic leukemia (APL), but it is contraindicated for patients on hemodialysis. We present a case of a patient with APL on hemodialysis, intubated, and with marked disseminated intravascular coagulation (DIC) who was successfully treated with ATRA. A 49-year-old man was transferred to our hospital and admitted into the intensive care unit due to renal dysfunction, DIC, and pneumonia. Promyelocytes were noted in the peripheral blood, and he was diagnosed with APL after bone-marrow examination. Because of renal dysfunction, only Ara-C was used but with a reduced dose. The patient's condition improved, and he was extubated and withdrawn from dialysis on the 5th day of hospitalization. The patient suffered from APL syndrome during induction therapy, which necessitated ATRA withdrawal and steroid administration. Remission was achieved after induction therapy, and the patient is currently on maintenance therapy. There are few cases of patients with APL on hemodialysis who were treated with ATRA; hence, it is necessary to review the treatment plan for these patients.

Cystic degeneration during neo-adjuvant chemotherapy predicts squamous metaplasia of triple negative breast cancer: report of two cases.

Neo-adjuvant chemotherapy (NAC) has become a standard treatment for advanced breast cancer because of the advantage of monitoring drug sensitivity and enabling breast-conserving therapy. The changes during NAC are also important to know the biological characteristics of the tumor. We experienced two cases with cystic degeneration and enhancement of the cyst wall during NAC for triple negative breast cancer (TNBC). They were diagnosed to have breast cancer with squamous metaplasia. In case 1, a 37-year-old woman with right breast cancer diagnosed as TNBC, T3N3M0, Stage 3b was treated with NAC. MRI showed a cystic degeneration with a diameter of 3.5 cm and enhancement of the cyst wall, and the other nodules were extinguished. The histopathological finding of the surgical specimen revealed solid tubular carcinoma with squamous metaplasia. In case 2, a 58-year-old woman with right breast cancer diagnosed as HER2 enriched subtype, T2N0M0 stage 2 was treated with NAC containing trastuzumab. The post-NAC MRI showed extinguishment of the mass in the right breast, but showed a cystic lesion with 24 mm in diameter and enhancement of its wall in the left breast. She underwent breast conserving surgery for bilateral breast cancer, and histopathological finding of the surgical specimen indicated complete remission of right breast cancer and squamous cell carcinoma developed in the left breast. These changes are impressive and remind us that there are metaplastic changes (especially for squamous metaplasia) with resistance to chemotherapy.

TP53-positive clones are responsible for drug-tolerant persister and recurrence of HER2-positive breast cancer.

PURPOSE: The prognosis of HER2-positive breast cancer has improved with the development of anti-HER2 therapies. In order to further improve the prognosis of HER2-positive breast cancer, it is essential to elucidate the cells that survive during the therapy (drug-tolerant persister DTP). METHODS: Of the 2022 breast cancer patients operated at our institution during 2004-2018, 240 (12%) had HER2-positive breast cancer. Neo-adjuvant chemotherapy including trastuzumab (Tr-NAC) was administered to 94 of them. Forty-six of them were complete remission (CR), and 48 were non-CR. After 6.9 ± 3.7 years of follow-up, all 46 CR cases showed no recurrence (Cohort A), and 48 non-CR cases were divided into 31 cases with no recurrence (Cohort B) and 17 cases with recurrence (Cohort C). In addition to clinical backgrounds, we compared genomic profiles for 27 patients (Cohort A; 15/48, B; 7/31, and C; 5/17) who consented to genomic analysis. RESULTS: Genomic abnormalities of TP53 and PIK3CA were frequently observed in biopsy samples pre Tr-NAC, but we found no differences between CR (Cohort A) and non-CR (Cohorts B + C). Then, we examined both of pre and post Tr-NAC samples of Cohort B (7) and C (5) to see the relationship between recurrence and genomic abnormalities. TP53 mutations were significantly more prevalent in Cohort C (5/5, 100%) than cohort B (3/7, 43%) in the surgical sample after treatment (p = 0.04). PyClone analysis of TP53 mutations showed that the cellular frequency of TP53 clones increased in 4 of 5 patients in Cohort C and none of B. On the other hand, we found no enhancement of PIK3CA mutant clones in Cohort C. CONCLUSIONS: The DTP after Tr-NAC associated with subsequent relapse had TP53 mutations, suggesting that overcoming DTP with TP53 mutations is the most important clinical challenge. TRIAL REGISTRATION: Not applicable.

Benefit of home parenteral nutrition (HPN) and chemotherapy in patients with invasive lobular carcinoma developed peritoneal metastases.

The benefit of home parenteral nutrition (HPN) for patients with malnutrition due to peritoneal metastasis depends on the type of cancer. During the period 1999-2020, we treated 460 patients with metastatic and stage 4 breast cancer, 23 of whom were invasive lobular carcinoma (ILC). Of the 23 patients with ILC, 13 (57%) developed peritoneal metastasis, and 11 died of progression of peritoneal metastasis. Among these 11 patients, 2 patients who underwent surgery due to bowel obstruction, had no improvement, and died 1-4 months after surgery. The prognosis of the other 7 patients under BSC alone was poor, survival time were ranging from 1 to 5 months. The remaining two patients who were able to continue outpatient chemotherapy under HPN were able to prolong their survival time by 18 months and 26 months, respectively. We need to recognize that HPN and chemotherapy may prolong survival time in patients with peritoneal metastasis of ILC, and determine the indication for HPN based on the non-peritoneal life-threatening metastasis, length of treatment, availability of support for HPN management and outpatient chemotherapy, and the patient's willingness to accept it.

[Two Cases of Carcinoma en Cuirasse, as Cutaneous Metastasis of Breast Cancer].

We present 2 cases of carcinoma en cuirasse, an uncommon clinical manifestation of metastatic cutaneous breast cancer. Case 1, a 70-year-old woman, presented with diffuse erythematous, indurated skin lesions that covered her entire anterior chest wall. Skin biopsy revealed tumor cells in the dermis which were ER and PgR positive and HER2 negative. CT showed pleural and pericardial effusion which led to a final diagnosis of cutaneous metastasis from breast cancer. Fulvestrant monotherapy was initiated and maintained a good clinical effect for 40 months. She died of multiple liver metastasis after 53 months from her first visit. Case 2 was a 71-year-old woman, with a 24 month history of a left breast tumor that gradually accompanied erythematous skin indurations and erosion, which spread to her entire left chest wall and contralateral breast. Following skin biopsy and CT, she was diagnosed to have triple negative breast cancer with multiple lymph node and cutaneous metastasis. After 4 cycles of EC, capecitabine was administrated and her skin lesions improved rapidly, including the lymph nodes. She is currently alive after 12 months since her first visit and under chemotherapy against new cutaneous metastasis.

Clinical Significance of Past History of Breast Cancer Screening for the Prognosis of Triple Negative Breast Cancer.

BACKGROUND/AIM: This study examined the prognostic impact of the past history of breast cancer screening within the last 2 years (PH-BCS), for patients with triple negative breast cancer (TNBC), a subtype that carries extremely poor prognosis. PATIENTS AND METHODS: Eighty-six consecutive cases with TNBC, who underwent surgery at our faculty from 2009 to 2015, were divided into two groups according to PH-BCS. Prognostic analyses for disease-free survival and overall survival between the two groups were performed. RESULTS: The positive PH-BCS group (n=44) had a significantly better prognoses than the negative PH-BCS group (n=42) (p<0.001). No recurrent cases were observed in the positive PH-BCS group. In the negative PH-BCS group, tumor and node status and chemotherapy were indicated as significant prognostic factors, and further step-wise multivariate analysis revealed only node status as a significant prognostic factor. CONCLUSION: Breast cancer screening at least every 2 years may improve the prognosis of TNBC.

Effect of oral immunotherapy in children with milk allergy: The ORIMA study.

BACKGROUND: This study was aimed at evaluating the efficacy and safety of oral immunotherapy (OIT) in children with severe cow's milk allergy. METHODS: The subjects comprised 28 children (aged 3-12 years) with allergic symptoms that were induced by ≤ 10 mL of cow's milk in an oral food challenge test (OFC). The subjects were randomly allocated to the treatment group (n = 14) and control group (n = 14); the former received rush immunotherapy for 2 weeks, followed by a gradual increase of cow's milk volume to 100 mL for 1 year, and the latter completely eliminated cow's milk for 1 year. Both groups underwent an OFC with 100 mL of cow's milk after 1 year. RESULTS: The treatment group had significantly higher rates of a negative OFC [7/14 (50%) vs. 0/14 (0%), p < 0.01] compared with the control group. The cow's milk-specific IgE level significantly decreased in the treatment group (p < 0.01) but not in the control group (p = 0.63). During the study period, adrenaline was required in 6/14 patients (43%) of the treatment group and in 0/14 patients (0%) of the control group. Long follow-up data were available at the 2-year point after the study for 8 in the treatment group and 7 (87.5%) of these continued to ingest milk (>100 mL). CONCLUSIONS: The effect of immunotherapy was 50%, but the incidence of adverse events was not low. Further studies focusing on safety is necessary to standardize OIT for cow's milk allergy.

Phospho­STAT1 expression as a potential biomarker for anti­PD­1/anti­PD­L1 immunotherapy for breast cancer.

In the present study, we evaluated the mechanisms of programmed death ligand 1 (PD­L1) expression in the breast cancer microenvironment, focusing on the role of interferon­Î³ (IFN­Î³), and the clinical indications for anti­programmed cell death 1 (PD­1) /anti­PD­L1 immunotherapy. We evaluated PD­L1 expression in 4 breast cancer cell lines in the presence of 3 types of inhibitors, as well as IFN­Î³. The expression of phosphorylated signal transducer and activator of transcription 1 (p­STAT1), one of the IFN­Î³ signaling pathway molecules, was analyzed using immunohistochemistry (IHC) in relation to PD­L1 and human leukocyte antigen (HLA) class I expression on cancer cells and tumor­infiltrating CD8­positive T cells in 111 patients with stage II/III breast cancer. Using The Cancer Genome Atlas (TCGA) database, the correlation of the IFN­Î³ signature with PD­L1 expression was analyzed in breast invasive carcinoma tissues. As a result, the JAK/STAT pathway via IFN­Î³ was mainly involved in PD­L1 expression in the cell lines examined. IHC analysis revealed that the PD­L1 and HLA class I expression levels were significantly upregulated in the p­STAT1­positive cases. TCGA analysis indicated that the PD­L1 expression and IFN­Î³ signature exhibited a positive correlation. On the whole, these findings suggest that PD­L1 and HLA class I are co­expressed in p­STAT1­positive breast cancer cells induced by IFN­Î³ secreted from tumor infiltrating immune cells, and that p­STAT1 expression may be a potential biomarker for patient selection for immunotherapy with anti­PD­1/anti­PD­L1 monoclonal antibodies.

Feasibility of Combination Therapy with Nab-paclitaxel Plus Gemcitabine in Patients with Recurrent Pancreatic Cancer.

BACKGROUND/AIM: Nab-paclitaxel plus gemcitabine (nab-P+Gem) is one of most reliable and effective regimens for borderline or unresectable pancreatic cancer (PC). However, the feasibility and clinical benefits of this regimen have never been evaluated for patients with recurrent PC after pancreatectomy. The aim of this study was to investigate the feasibility of combination therapy with nab-paclitaxel plus gemcitabine (nab-P+Gem) for patients with recurrent PC. PATIENTS AND METHODS: Twenty-two patients with recurrent PC received an intravenous infusion of nab-P (125 mg/m2) and Gem (1,000 mg/m2) on days 1, 8, and 15 of a 4-week cycle. The primary end-point of this study was completion of the 4 cycles. The secondary end-points were the safety, efficacy, and disease control rate. RESULTS: The treatment completion rate of the 4 cycles was 90.9%. The objective response rate was 13.6% and the disease control rate was 63.6%. The median progression-free survival was 7.2 months. The most common grade 3 or higher hematological toxicity was neutropenia (72.7%). There was no treatment-related death. Furthermore, the chemotherapeutic effects varied with the time of recurrence. CONCLUSION: Combination nab-P+Gem therapy was well-tolerated and effective in patients with recurrent PC.

[A Case of Triple Negative Breast Cancer Successfully Treated with S-1].

A 73-year-old woman noticed a mass in her right breast about 1 year ago and consulted our hospital for an enlarged mass of about 10 cm in diameter.She was diagnosed with locally advanced triple negative breast cancer, and we initiated S-1 treatment as neoadjuvant chemotherapy.After 4 chemotherapy courses, computed tomography showed that the primary tumor had shrunk.Therefore, right mastectomy and axillary dissection were performed, and UFT was administered after surgery.She is currently alive with no recurrence 18 months after surgery.

Successful laparoscopic partial gastrectomy and spleen-preserving distal pancreatectomy for gastric duplication cyst connecting with the pancreatic tail.

INTRODUCTION: Gastrointestinal duplication cyst is a congenital rare disease that may occur in any region from mouth to anus. Among them, gastric duplication cysts are very rare. CASE REPORT: Here we report A 23-year-old Japanese man who visited our hospital to evaluate an abdominal tumor. Abdominal computed tomography showed a well-circumscribed homogenous low-density mass measuring 6.2 × 6.0 cm between the pancreatic tail and the upper posterior wall on the gastric greater curvature, and the mass seemed to originate from the pancreatic tail. We found intraoperatively that the mass adhered to the stomach and pancreatic tail strongly, so we performed laparoscopic partial gastrectomy and spleen-preserving distal pancreatectomy. Pathological findings showed that the lining epithelium of the cystic mass consisted of the gastric foveolar epithelium with fundic glands. Furthermore, the pancreatic tissue of the pancreatic tail and the muscular layer of the cystic mass were intermingled. DISCUSSION: GDCs are usually diagnosed at a younger age and in adults, they are very rare. Therefore, surgical resection is considered to be the best treatment due to the difficulty of diagnosis, and also that it mimics a pancreatic cystic tumor, and malignant transformation. Complete resection of the cyst is the ideal technique and laparoscopic surgery should be selected whenever possible. CONCLUSION: We experienced a case of GDC continuous to both stomach and pancreatic tail. Laparoscopic surgery is safety and useful even if GDC is continuous with both the stomach and the pancreas.

Pharmacist-led intervention in the multidisciplinary team approach optimizes heart failure medication.

We evaluated the impact of pharmacist-led heart failure (HF) drug recommendations during hospitalization for hospitalized patients with HF. Hospitalized patients with HF were retrospectively reviewed. Patients were hospitalized before (n = 208, non-intervention group) or after (n = 170, intervention group) the launch of the HF multidisciplinary team (HFMDT) approach with pharmacist-led HF medication optimization. There were no significant group differences in patient background characteristics at admission. Patients with HF with reduced ejection fraction who were not on beta blockers or angiotensin-converting enzyme inhibitor/angiotensin receptor blockers (ACE-I/ARB) at admission were significantly more likely to be on beta blockers at the time of discharge in the intervention group (73.3 vs 96.3%, P = 0.027) compared to those in non-intervention group; however, the change in ACE-I/ARB prescriptions was not significant (53.3 vs 63.3%, P = 0.601). The proportion of patients on any drug with recommendations against its use in patients with HF did not change from admission to discharge in the non-intervention group (21.2 vs. 20.2%, P = 0.855), but was significantly reduced in the intervention group (22.9 vs. 12.9%, P = 0.005). There were no group differences in the in-hospital all-cause mortality (non-intervention, 3.4%; intervention, 2.4%; P = 0.761) or length of hospital stay (median: non-intervention, 13 days; intervention, 14 days; P = 0.508). Pharmacist-led HF drug recommendations during hospitalization as part of a HFMDT approach for hospitalized patients with HF can increase beta blocker prescriptions and decrease non-preferred drug prescriptions.

An Aliphatic Ester Diisopropyl Sebacate Exhibited an Adjuvant Effect on Fluorescein Isothiocyanate-Induced Contact Hypersensitivity Mouse Models.

Alternative plasticizers have become more popular due to health concerns about phthalate esters. We demonstrated that phthalate esters enhanced skin sensitization to fluorescein isothiocyanate (FITC) in mouse contact hypersensitivity models. Alternative plasticizers have not been well studied as to their effect on the immune system. We previously found that diisopropyl adipate (DIPA), an aliphatic dicarboxylic acid ester, enhanced skin sensitization to FITC. Sebacate esters are also widely used as alternative plasticizers. Here we tested diisopropyl sebacate (DIPS), which has the same alcohol with an aliphatic dicarboxylic acid of longer chain, using BALB/c mice. The results showed that DIPS facilitated skin sensitization to FITC and increased FITC-presenting dendritic cell trafficking from the skin to draining lymph nodes. Furthermore, DIPS activated transient receptor potential ankyrin 1 (TRPA1). The latter feature has been commonly observed for phthalate esters and DIPA, which have adjuvant effects. In summary, the adjuvant effect of a sebacate ester was demonstrated in a mouse model.

Selection of broad-spectrum cephalosporin-resistant Escherichia coli in the feces of healthy dogs after administration of first-generation cephalosporins.

Although antimicrobial products are essential for treating diseases caused by bacteria, antimicrobial treatment selects for antimicrobial-resistant (AMR) bacteria. The aim of this study was to determine the effects of administration of first-generation cephalosporins on development of resistant Escherichia coli in dog feces. The proportions of cephalexin (LEX)-resistant E. coli in fecal samples of three healthy dogs treated i.v. with cefazolin before castration and then orally with LEX for 3 days post-operation (PO) were examined using DHL agar with or without LEX (50 µg/mL). LEX-resistant E. coli were found within 3 days PO, accounted for 100% of all identified E. coli 3-5 days PO in all dogs, and were predominantly found until 12 days PO. LEX-resistant E. coli isolates on DHL agar containing LEX were subjected to antimicrobial susceptibility testing, pulsed-field gel electrophoresis (PFGE) genotyping, ß-lactamase typing and plasmid profiling. All isolates tested exhibited cefotaxime (CTX) resistance (CTX minimal inhibitory concentration ≥4 µg/mL). Seven PFGE profiles were classified into five groups and three ß-lactamase combinations (blaCMY-4 -blaTEM-1 , blaTEM-1 -blaCTX-M-15 and blaTEM-1 -blaCTX-M-15 -blaCMY-4 ). All isolates exhibited identical PFGE profiles in all dogs on four days PO and subsequently showed divergent PFGE profiles. Our results indicate there are two selection periods for AMR bacteria resulting from the use of antimicrobials. Thus, continuing hygiene practices are necessary to prevent AMR bacteria transfer via dog feces after antimicrobial administration.

Identification and characterization of cytosolic fructose-1,6-bisphosphatase in Euglena gracilis.

Euglena gracilis has the ability to accumulate a storage polysaccharide, a ß-1,3-glucan known as paramylon, under aerobic conditions. Under anaerobic conditions, E. gracilis cells degrade paramylon and synthesize wax esters. Cytosolic fructose-1,6-bisphosphatase (FBPase) appears to be a key enzyme in gluconeogenesis and position branch point of carbon partitioning between paramylon and wax ester biosynthesis. We herein identified and characterized cytosolic FBPase from E. gracilis. The Km and Vmax values of EgFBPaseIII were 16.5 ± 1.6 µM and 30.4 ± 7.2 µmol min(-1) mg protein(-1), respectively. The activity of EgFBPaseIII was not regulated by AMP or reversible redox modulation. No significant differences were observed in the production of paramylon in transiently suppressed EgFBPaseIII gene expression cells by RNAi (KD-EgFBPaseIII); nevertheless, FBPase activity was markedly decreased in KD-EgFBPaseIII cells. On the other hand, the growth of KD-EgFBPaseIII cells was slightly higher than that of control cells.

Enhancement of photosynthetic capacity in Euglena gracilis by expression of cyanobacterial fructose-1,6-/sedoheptulose-1,7-bisphosphatase leads to increases in biomass and wax ester production.

BACKGROUND: Microalgae have recently been attracting attention as a potential platform for the production of biofuels. Euglena gracilis, a unicellular phytoflagellate, has been proposed as an attractive feedstock to produce biodiesel because it can produce large amounts of wax esters, consisting of medium-chain fatty acids and alcohols with 14:0 carbon chains. E. gracilis cells highly accumulate a storage polysaccharide, a ß-1,3-glucan known as paramylon, under aerobic conditions. When grown aerobically and then transferred into anaerobic conditions, E. gracilis cells degrade paramylon to actively synthesize and accumulate wax esters. Thus, the enhanced accumulation of paramylon through the genetic engineering of photosynthesis should increase the capacity for wax ester production. RESULTS: We herein generated transgenic Euglena (EpFS) cells expressing the cyanobacterial fructose-1,6-/sedoheptulose-1,7-bisphosphatase (FBP/SBPase), which is involved in the Calvin cycle, to enhance its photosynthetic activity. FBP/SBPase was successfully expressed within Euglena chloroplasts. The cell volume of the EpFS4 cell line was significantly larger than that of wild-type cells under normal growth conditions. The photosynthetic activity of EpFS4 cells was significantly higher than that of wild type under high light and high CO2, resulting in enhanced biomass production, and the accumulation of paramylon was increased in transgenic cell lines than in wild-type cells. Furthermore, when EpFS cell lines grown under high light and high CO2 were placed on anaerobiosis, the productivity of wax esters was approximately 13- to 100-fold higher in EpFS cell lines than in wild-type cells. CONCLUSION: Our results obtained here indicate that the efficiency of biomass production in E. gracilis can be improved by genetically modulating photosynthetic capacity, resulting in the enhanced production of wax esters. This is the first step toward the utilization of E. gracilis as a sustainable source for biofuel production under photoautotrophic cultivation.

Adjuvant Effect of an Alternative Plasticizer, Diisopropyl Adipate, on a Contact Hypersensitivity Mouse Model: Link with Sensory Ion Channel TRPA1 Activation.

Due to health concerns about phthalate esters, the use of alternative plasticizers is being considered. Phthalate esters enhance skin sensitization to fluorescein isothiocyanate (FITC) in mouse models. We have demonstrated that phthalate esters stimulate transient receptor potential ankyrin 1 (TRPA1) cation channels expressed on sensory neurons. We also found a correlation between TRPA1 activation and the enhancing effect on FITC-induced contact hypersensitivity (CHS) when testing various types of phthalate esters. Here we investigated the effects of an alternative plasticizer, diisopropyl adipate (DIA). Activation of TRPA1 by DIA was demonstrated by calcium mobilization using Chinese hamster ovary cells expressing TRPA1 in vitro. The effect of DIA was inhibited by a TRPA1-specific antagonist, HC-030031. The presence of DIA or dibutyl phthalate (DBP; positive control) during skin sensitization of BALB/c mice to FITC augmented the CHS response, as revealed by the level of ear-swelling. The enhancing effect of DIA was inhibited by in vivo pretreatment with HC-030031. FITC-presenting CD11c(+) dendritic cell (DC)-trafficking to draining lymph nodes was facilitated both by DIA and by DBP. DBP and DIA were similarly active in the enhancement of interferon-γ production by draining lymph nodes, but the effect on interleukin-4 production was weaker with DIA. Overall, DIA activated TRPA1 and enhanced FITC-induced CHS, as DBP did. The adjuvant effects of adipate esters may need to be considered because they are used as ingredients in cosmetics and drug formulations topically applied to the skin.

Characterization and physiological role of two types of chloroplastic fructose-1,6-bisphosphatases in Euglena gracilis.

The chloroplastic fructose-1,6-bisphosphatase (FBPase) is a late-limiting enzyme in the Calvin cycle. In the present study, we isolated and characterized the cDNAs encoding two types of chloroplastic FBPase isoforms (EgFBPaseI and II) from Euglena gracilis. The Km values of recombinant EgFBPaseI and EgFBPaseII for fructose 1,6-bisphosphate (Fru 1,6-P2) were 165 ± 17 and 2200 ± 200 µM, respectively. The activity of EgFBPaseI was inhibited by 1mM H2O2 and recovered when incubated with DTT. The activity of EgFBPaseII was resistant to concentrations of H2O2 up to 1mM, which was distinct from those of EgFBPaseI and spinach chloroplastic FBPase. The suppression of EgFBPaseI gene expression by gene silencing markedly decreased photosynthetic activity and inhibited cell growth. The results of the present study clearly demonstrated that EgFBPaseI played a critical role in photosynthesis in Euglena chloroplasts.

Loss of osteoblast Runx3 produces severe congenital osteopenia.

Congenital osteopenia is a bone demineralization condition that is associated with elevated fracture risk in human infants. Here we show that Runx3, like Runx2, is expressed in precommitted embryonic osteoblasts and that Runx3-deficient mice develop severe congenital osteopenia. Runx3-deficient osteoblast-specific (Runx3(fl/fl)/Col1α1-cre), but not chondrocyte-specific (Runx3(fl/fl)/Col1α2-cre), mice are osteopenic. This demonstrates that an osteoblastic cell-autonomous function of Runx3 is required for proper osteogenesis. Bone histomorphometry revealed that decreased osteoblast numbers and reduced mineral deposition capacity in Runx3-deficient mice cause this bone formation deficiency. Neonatal bone and cultured primary osteoblast analyses revealed a Runx3-deficiency-associated decrease in the number of active osteoblasts resulting from diminished proliferation and not from enhanced osteoblast apoptosis. These findings are supported by Runx3-null culture transcriptome analyses showing significant decreases in the levels of osteoblastic markers and increases in the levels of Notch signaling components. Thus, while Runx2 is mandatory for the osteoblastic lineage commitment, Runx3 is nonredundantly required for the proliferation of these precommitted cells, to generate adequate numbers of active osteoblasts. Human RUNX3 resides on chromosome 1p36, a region that is associated with osteoporosis. Therefore, RUNX3 might also be involved in human bone mineralization.

A gain-of-function mutation of plastidic invertase alters nuclear gene expression with sucrose treatment partially via GENOMES UNCOUPLED1-mediated signaling.

Plastid gene expression (PGE) is one of the signals that regulate the expression of photosynthesis-associated nuclear genes (PhANGs) via GENOMES UNCOUPLED1 (GUN1)-dependent retrograde signaling. We recently isolated Arabidopsis sugar-inducible cotyledon yellow-192 (sicy-192), a gain-of-function mutant of plastidic invertase, and showed that following the treatment of this mutant with sucrose, the expression of PhANGs as well as PGE decreased, suggesting that the sicy-192 mutation activates a PGE-evoked and GUN1-mediated retrograde pathway. To clarify the relationship between the sicy-192 mutation, PGE, and GUN1-mediated pathway, plastid and nuclear gene expression in a double mutant of sicy-192 and gun1-101, a null mutant of GUN1 was studied. Plastid-encoded RNA polymerase (PEP)-dependent PGE was markedly suppressed in the sicy-192 mutant by the sucrose treatment, but the suppression as well as cotyledon yellow phenotype was not mitigated by GUN1 disruption. Microarray analysis revealed that the altered expression of nuclear genes such as PhANG in the sucrose-treated sicy-192 mutant was largely dependent on GUN1. The present findings demonstrated that the sicy-192 mutation alters nuclear gene expression with sucrose treatment via GUN1, which is possibly followed by inhibiting PEP-dependent PGE, providing a new insight into the role of plastid sugar metabolism in nuclear gene expression.