ECERIFERUM 10 Encoding an Enoyl-CoA Reductase Plays a Crucial Role in Osmotolerance and Cuticular Wax Loading in Arabidopsis

Acquired osmotolerance induced after salt stress is widespread across Arabidopsis thaliana (Arabidopsis) accessions (e.g., Bu-5). However, it remains unclear how this osmotolerance is established. Here, we isolated a mutant showing an acquired osmotolerance-defective phenotype (aod2) from an ion-beam-mutagenized M2 population of Bu-5. aod2 was impaired not only in acquired osmotolerance but also in osmo-shock, salt-shock, and long-term heat tolerances compared with Bu-5, and it displayed abnormal morphology, including small, wrinkled leaves, and zigzag-shaped stems. Genetic analyses of aod2 revealed that a 439-kbp region of chromosome 4 was translocated to chromosome 3 at the causal locus for the osmosensitive phenotype. The causal gene of the aod2 phenotype was identical to ECERIFERUM 10 (CER10), which encodes an enoyl-coenzyme A reductase that is involved in the elongation reactions of very-long-chain fatty acids (VLCFAs) for subsequent derivatization into cuticular waxes, storage lipids, and sphingolipids. The major components of the cuticular wax were accumulated in response to osmotic stress in both Bu-5 WT and aod2. However, less fatty acids, primary alcohols, and aldehydes with chain length ≥ C30 were accumulated in aod2. In addition, aod2 exhibited a dramatic reduction in the number of epicuticular wax crystals on its stems. Endoplasmic reticulum stress mediated by bZIP60 was increased in aod2 under osmotic stress. The only cer10 showed the most pronounced loss of epidermal cuticular wax and most osmosensitive phenotype among four Col-0-background cuticular wax-related mutants. Together, the present findings suggest that CER10/AOD2 plays a crucial role in Arabidopsis osmotolerance through VLCFA metabolism involved in cuticular wax formation and endocytic membrane trafficking.

Magnetic resonance imaging findings of pure prostatic ductal adenocarcinomas: a case series

PURPOSE

This study aimed to investigate the characteristics of magnetic resonance imaging (MRI) findings in pure prostatic ductal adenocarcinoma.

METHODS

From January 2009 to February 2020, seven patients who were diagnosed with pure prostatic ductal adenocarcinoma and had a referable preoperative MRI scan were included in the study. We evaluated the following MRI findings for each tumor: size, location, presence of multi-cystic component, and apparent diffusion coefficient (ADC) value.

RESULTS

The median maximum diameter of the tumors was 22 mm (range 19-70 mm). Regarding transverse distribution, five tumors were located in the periurethral area and two were located peripherally apart from the urethra. Two of the seven tumors had cystic components. The median ADC value of the tumors was 0.754 × 10^-3 mm²/s (range 0.570-0.963 × 10^-3 mm²/s). Based on the transverse distribution and components of the tumors on MRI, ductal adenocarcinomas were classified into three types: type I as a non-cystic tumor located peripherally apart from the urethra (29%, two cases); type II as a non-cystic tumor located in the periurethral area (43%, three cases); and type III as a tumor with a multi-cystic component (29%, two cases).

CONCLUSION

The non-cystic mass with periurethral distribution (type II) and multi-cystic mass (type III) may be characteristic features that differentiate pure ductal adenocarcinoma from ordinary acinar adenocarcinoma on MRI.

An anomalous hyperplastic anterior choroidal artery associated with an unruptured internal carotid–posterior communicating artery aneurysm

The anterior choroidal artery (AChA) injuries can result in severe neurologic deficits, so requiring careful observation to avoid inadvertent damage during neuroendovascular procedures. In this case report, we present the unusual case of an anomalous hyperplastic AChA associated with a fetal-type posterior communicating artery (PCoA), and an unruptured internal carotid artery (ICA) –PCoA aneurysm. A 54-year-old woman presented with persistent headache. Brain magnetic resonance imaging (MRI) showed an unruptured cerebral aneurysm in the right ICA, and cerebral angiography revealed a proximal fetal-type PComA and a distal anomalous hyperplastic AChA. Coil embolization was performed with no neurologic deficits and the target lesion was embolized with a total of 6 coils. An anomalous hyperplastic AchA has a lengthy course with numerous choroidal and perforating branches, and therefore, an abundant perfusion region. Thorough knowledge of the development and anatomy of anomalous arteries is important for safely performing endovascular procedures without causing any ischemic complications.

Systemic Vasculitis Following SARS-CoV-2 mRNA Vaccination Demonstrated on FDG PET/CT

ABSTRACT

Causality regarding adverse events following SARS-CoV-2 mRNA vaccine is undetermined for vasculitis. Herein, we report the case of an 80-year-old man who presented with a persistent high fever of 7 days' duration that began shortly after receiving a COVID-19 vaccination. There was also a complaint of persistent lower limb pain and walking difficulty on emergency transportation. FDG PET/CT demonstrated extensive linear hypermetabolic foci along the vessels of both legs, including the hips, and the arms, supraclavicular area, chest wall, and temporal regions, suggesting systemic vasculitis. Subsequent temporal artery biopsy revealed arteritis, which is not typical of giant cell arteritis.

Ecdysone coordinates plastic growth with robust pattern in the developing wing

Animals develop in unpredictable, variable environments. In response to environmental change, some aspects of development adjust to generate plastic phenotypes. Other aspects of development, however, are buffered against environmental change to produce robust phenotypes. How organ development is coordinated to accommodate both plastic and robust developmental responses is poorly understood. Here, we demonstrate that the steroid hormone ecdysone coordinates both plasticity of organ size and robustness of organ pattern in the developing wings of the fruit fly Drosophila melanogaster. Using fed and starved larvae that lack prothoracic glands, which synthesize ecdysone, we show that nutrition regulates growth both via ecdysone and via an ecdysone-independent mechanism, while nutrition regulates patterning only via ecdysone. We then demonstrate that growth shows a graded response to ecdysone concentration, while patterning shows a threshold response. Collectively, these data support a model where nutritionally regulated ecdysone fluctuations confer plasticity by regulating disc growth in response to basal ecdysone levels and confer robustness by initiating patterning only once ecdysone peaks exceed a threshold concentration. This could represent a generalizable mechanism through which hormones coordinate plastic growth with robust patterning in the face of environmental change.

Insulin signaling couples growth and early maturation to cholesterol intake in Drosophila

Nutrition is one of the most important influences on growth and the timing of maturational transitions including mammalian puberty and insect metamorphosis. Childhood obesity is associated with precocious puberty, but the assessment mechanism that links body fat to early maturation is unknown. During development, the intake of nutrients promotes signaling through insulin-like systems that govern the growth of cells and tissues and also regulates the timely production of the steroid hormones that initiate the juvenile-adult transition. We show here that the dietary lipid cholesterol, which is required as a component of cell membranes and as a substrate for steroid biosynthesis, also governs body growth and maturation in Drosophila via promoting the expression and release of insulin-like peptides. This nutritional input acts via the nutrient sensor TOR, which is regulated by the Niemann-Pick-type-C 1 (Npc1) cholesterol transporter, in the glia of the blood-brain barrier and cells of the adipose tissue to remotely drive systemic insulin signaling and body growth. Furthermore, increasing intracellular cholesterol levels in the steroid-producing prothoracic gland strongly promotes endoreduplication, leading to an accelerated attainment of a nutritional checkpoint that normally ensures that animals do not initiate maturation prematurely. These findings, therefore, show that a Npc1-TOR signaling system couples the sensing of the lipid cholesterol with cellular and systemic growth control and maturational timing, which may help explain both the link between cholesterol and cancer as well as the connection between body fat (obesity) and early puberty.

Rare case of retropubic parasymphyseal cyst in a male patient

INTRODUCTION

Retropubic parasymphyseal cysta are rare, and few cases have been reported in men.

CASE PRESENTATION

A 65-year-old male patient presented with a 6-month history of pelvic and perineal pain. Magnetic resonance imaging revealed a high-intensity, irregular-shaped mass extending from the pubic symphysis to the bladder. Contrast enhancement revealed no uptake in the central part of the mass, indicating a cystic component. Computed tomography showed erosion of the pubic symphysis and pubic osteophytes. Pathological findings of biopsy specimens revealed inflammatory fibrous tissue but no malignancy. The definitive diagnosis was retropubic parasymphyseal cyst associated with inflammation. The patient was treated with cefazolin from 1 day before surgery until postsurgical day 7. Oral antibiotic therapy was then prescribed for 1 month to maximize treatment. After 2 months, the patient's symptoms resolved.

CONCLUSION

Retropubic parasymphyseal cysts with inflammation and smaller asymptomatic cysts can be managed effectively with conservative or minimally invasive treatment.

Fatal Immune Checkpoint Inhibitor-related Pancreatitis

We herein report a case of fatal pancreatitis induced by an immune checkpoint inhibitor. A 62-year-old man with cancer of unknown primary was treated with pembrolizumab. After 12 cycles, immune-related pneumonitis developed and was treated with prednisolone. Three months later, pancreatitis developed, which was successfully treated with hydration and protease inhibitors. Eight months later, another attack of pancreatitis occurred, which did not respond to therapy, including high-dose corticosteroids, and he eventually died. This is the first report describing fatal immune checkpoint inhibitor-related pancreatitis. Despite the rarity of this complication, attention should be paid to its potential severity and treatment.

[A Case of Myeloid Sarcoma in the Small Intestine Presenting with Intussusception]

A sixty-something man presented with lower abdominal pain in early Y month 20XX, and was examined at the hospital's internal medicine outpatient clinic. An abdominal CT showed a soft tissue mass around the left hip joint, and multiple enlarged lymph nodes from inside the pelvis to the mesentery of the abdomen. We noted a small-intestinal intussusception in the lower right abdomen, and suspected malignant lymphoma. We did a CT-guided biopsy on the left hip joint soft tissue mass, and performed surgery on the small-intestinal intussusception. During surgery, we noted an approximately 30 cm ileal intussusception located about 60 cm from the terminal ileum, and enlarged lymph nodes in the nearby mesentery. We removed the ileal intussusception. The pathological diagnosis was myeloid sarcoma, and the soft tissue mass in the left hip joint was also diagnosed as myeloid sarcoma. We performed a bone-marrow biopsy at the hematology department, and diagnosed acute myeloid leukemia M2. We then started remission-induction therapy and consolidation therapy, and the patient was diagnosed as in remission in Y+5 month 20XX. We also need to keep in mind myeloid sarcoma in the intestine as a subtype of acute myeloid leukemia, as malignant tumor in the small intestine presenting with intussusception.

Association of device-measured physical activity with peak oxygen consumption measured by cardiopulmonary exercise testing in patients with cardiac implantable electronic devices

PURPOSE

Cardiac implantable electronic devices (CIEDs) offer diagnostic information such as device-measured physical activity (PA). Peak oxygen consumption (VO₂) measured by cardiopulmonary exercise testing (CPET) is the most objective variable showing exercise capacity. The purpose of this study was to investigate the relationship between these 2 variables.

METHODS

We retrospectively studied consecutive patients with CIEDs undergoing CPET between April 1, 2018, and January 31, 2021. These patients were divided into 2 groups: patients with peak VO₂ ≤ 14 ml/kg/min (low peak VO₂ group) and those showing peak VO₂ > 14 ml/kg/min (high peak VO₂ group). The peak device-measured PA was compared between the 2 groups. The relationship between the peak device-measured PA and peak VO₂ was also investigated.

RESULTS

There were 50 and 51 patients in the low and high peak VO₂ groups, respectively. The peak device-measured PA, which was expressed in units of hours/day, was significantly lower in the low peak VO₂ group than in the high peak VO₂ group (3.06, interquartile range [2.43-4.00] vs. 5.50, interquartile range [4.04-6.70] p < 0.01). The peak device-measured PA and peak VO₂ showed a significant positive correlation (Spearman's ρ = 0.53; p < 0.01). Furthermore, receiver operating characteristic curve analysis showed that a peak device-measured PA > 3.87 h/day could predict high peak VO₂ (80.4%, sensitivity; 72.0%, specificity). In multivariate linear regression analysis, peak device-measured PA was an independent predictor of peak VO₂ (regression coefficient, 0.61; 95% confidence interval, 0.33-0.89; p < 0.01).

CONCLUSIONS

Peak device-measured PA was significantly associated with peak VO₂.

Co-option of immune effectors by the hormonal signalling system triggering metamorphosis in Drosophila melanogaster

Insect metamorphosis is triggered by the production, secretion and degradation of 20-hydroxyecdysone (ecdysone). In addition to its role in developmental regulation, increasing evidence suggests that ecdysone is involved in innate immunity processes, such as phagocytosis and the induction of antimicrobial peptide (AMP) production. AMP regulation includes systemic responses as well as local responses at surface epithelia that contact with the external environment. At pupariation, Drosophila melanogaster increases dramatically the expression of three AMP genes, drosomycin (drs), drosomycin-like 2 (drsl2) and drosomycin-like 5 (drsl5). We show that the systemic action of drs at pupariation is dependent on ecdysone signalling in the fat body and operates via the ecdysone downstream target, Broad. In parallel, ecdysone also regulates local responses, specifically through the activation of drsl2 expression in the gut. Finally, we confirm the relevance of this ecdysone dependent AMP expression for the control of bacterial load by showing that flies lacking drs expression in the fat body have higher bacterial persistence over metamorphosis. In contrast, local responses may be redundant with the systemic effect of drs since reduction of ecdysone signalling or of drsl2 expression has no measurable negative effect on bacterial load control in the pupa. Together, our data emphasize the importance of the association between ecdysone signalling and immunity using in vivo studies and establish a new role for ecdysone at pupariation, which impacts developmental success by regulating the immune system in a stage-dependent manner. We speculate that this co-option of immune effectors by the hormonal system may constitute an anticipatory mechanism to control bacterial numbers in the pupa, at the core of metamorphosis evolution.

MK-6, a novel not-α IL-2, elicits a potent antitumor activity by improving the effector to regulatory T cell balance

IL-2 is a pleiotropic cytokine that regulates immune cell homeostasis. Its immunomodulatory function has been used clinically as an active immunotherapy agent for metastatic cancers. However, severe adverse effects, including the vascular leak syndrome and the preferential stimulation of anti-immunogenic Treg rather than effector T cells, have been obstacles. We newly designed a mutein IL-2, Mutakine-6 (MK-6), with reduced IL-2Rα-binding capability. MK-6 induced comparable cell growth potential toward IL-2Rβγ-positive T cells but was far less efficient in in vitro Treg proliferation and STAT5 activation. Unlike IL-2, in vivo administration of MK-6 produced minimal adverse effects. Using CT26 and B16F10-syngeneic tumor models, we found MK-6 was highly efficacious on tumor regression. Serum albumin conjugation to MK-6 prolonged in vivo half-life and accumulated in CT26 tumors, showing enhanced antitumor effect. Tumor-infiltrating leukocytes analysis revealed that albumin-fused MK-6 increased the ratio of effector CD8⁺ T cells to CD4⁺ Treg cells. These results demonstrated that MK-6 is an efficient immunomodulator potentially used for improved immunotherapy with decreased adverse effects and attenuated Treg stimulation.

Single-cell RNA-seq analysis reveals penaeid shrimp hemocyte subpopulations and cell differentiation process

Crustacean aquaculture is expected to be a major source of fishery commodities in the near future. Hemocytes are key players of the immune system in shrimps; however, their classification, maturation, and differentiation are still under debate. To date, only discrete and inconsistent information on the classification of shrimp hemocytes has been reported, showing that the morphological characteristics are not sufficient to resolve their actual roles. Our present study using single-cell RNA sequencing revealed six types of hemocytes of Marsupenaeus japonicus based on their transcriptional profiles. We identified markers of each subpopulation and predicted the differentiation pathways involved in their maturation. We also predicted cell growth factors that might play crucial roles in hemocyte differentiation. Different immune roles among these subpopulations were suggested from the analysis of differentially expressed immune-related genes. These results provide a unified classification of shrimp hemocytes, which improves the understanding of its immune system.

MRI, CT and FDG-PET/CT findings of Wolffian tumor: four-case series

Purpose

The purpose of this study is to describe the characteristic MRI, CT, and ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) findings of Wolffian tumor.

Methods

We reviewed preoperative images in four surgical cases of Wolffian tumor. MRI was available for review in all cases with additional diffusion-weighted images (DWI) in three, and contrast-enhanced images in two. CT was available in three. FDG-PET/CT was obtained in two.

Results

Two patients were asymptomatic, while the other two presented with acute abdomen. On MRI, all tumors were well-defined masses of increased signals on T2WI. Three tumors were solid, whereas the other was solid and cystic. The normal ipsilateral ovary was identified in two patients of reproductive ages, but not in two postmenopausal patients. Tumors in two patients presented with acute abdomen were complicated by hemorrhage. All three tumors evaluated on DWI showed high intensities. Contrast-enhanced images of MRI and CT showed homogeneous enhancement as the same degree as the myometrium. On CT, one tumor contained punctate calcifications. FDG-PET/CT showed moderate FDG accumulation.

Conclusion

Wolffian tumors may be typically solid extraovarian tumors occasionally associated with cysts and calcifications. Although they are benign, they mimic malignancy due to high intensities on DWI and increased FDG accumulation.

POS1482-HPR PAIN CATASTROPHIZING IS ASSOCIATED WITH RESIDUAL PAIN AFTER REACHING IMPROVED CONDITIONS OF SWOLLEN/TENDER JOINTS AND SERUM C-REACTIVE PROTEIN LEVEL

Background:

It has long been recognized that immune-mediated inflammatory diseases, such as rheumatoid arthritis (RA), are prone to coexist with depression due to the effects of cytokines, and that these two illnesses lead to an elevation in patients’ pain. However, we often encounter patients with RA who suffer from residual pain despite an improvement in disease activity and inflammation. The specific psychological factors associated with residual pain have not yet been clarified. In addition to the traditional psychological factors, such as depression and anxiety, we focused on pain catastrophizing due to the distortion of pain perception and explored its association with residual pain.

Objectives:

To examine whether psychological factors, such as pain catastrophizing, depression, and anxiety, are associated with self-reported pain visual analogue scale (pain-VAS) scores in RA patients with 1 or less on 28joints- swollen/tender counts (SJC/TJC) and CRP.

Methods:

This was a cross-sectional study of 290 RA outpatients (85% of whom were women) with scores of less than 1 on SJC, TJC, and CRP, with a median (IQR) age of 66 (57–73) years. The participants completed questionnaires, including pain VAS (0–100 mm), Pain Catastrophizing Scale (PCS, 0–52 scale), and Hospital Depression and Anxiety Scale (HADS, 0–42 scale). Using linear regression analyses, we analysed whether PC (PCS ≥30), depression (HADS-D ≥11), and anxiety (HADS-A ≥11) (independent variables) were associated with pain VAS scores (dependent variable). After univariate regression analysis, multivariate analysis adjusted for confounding factors was performed.

Results:

Patients reported a wide range of pain severity with a median (range) pain VAS score of 9 (0–96mm). The prevalence of anxiety and depression were 5.5% and 5.9%, respectively. Meanwhile, 24.1% of the patients experienced pain catastrophizing. Pain catastrophizing was associated with pain VAS scores in univariate and multivariate analyses (Table 1). The presence of anxiety and depression was not associated with pain VAS scores in any model. Multivariate analysis of other covariates showed that age, disease duration, and presence of SJC/TJC of joints other than the 28 joints were positively correlated with pain VAS scores.

Table 1.

Univariate and multivariate regression analysis for independent variables associated with pain-VAS scores

UnivariateMultivariate independent variablesModel 1*Model 2**Pain catastrophizingEstimate3.74.13.695%CI 0.7 to 6.61.1 to 7.00.5 to 6.6p-value0.0150.0060.021AnxietyEstimate3.74.40.595%CI -1.9 to 9.2 -1.0 to 9.9 -3.5 to 7.9p value0.1980.1080.453DepressionEstimate3.54.23.995%CI -1.9 to 8.9 -1.1 to 9.5 -1.9 to 8.7p-value0.2040.1190.210

The covariates in multivariate analysis are as follows: age, sex, body mass index, disease duration, Steinbrocker’s Stage, prednisolone dosage, biologic agents use, and presence of swollen joint counts/tender joint counts of joints other than the 28 joints.

*Model 1: each psychological independent variable and the above covariates.

**Model 2: all psychological independent variables and the above covariates.

Conclusion:

Pain catastrophizing was associated with pain VAS scores in RA patients with 1 or less on 28joints-SJC/TJC and CRP, emphasising that residual pain in the patients should be treated in a biopsychosocial framework focussing on pain catastrophizing.

Disclosure of Interests:

Tamami Yoshida: None declared, Motomu Hashimoto Speakers bureau: Mitsubishi Tanabe Pharma Corporation; Bristol-Myers Squibb; Eisai Co., Ltd.; and Eli Lilly and Company., Grant/research support from: Mitsubishi Tanabe Pharma Corporation; Bristol-Myers Squibb; Eisai Co., Ltd.; and Eli Lilly and Company., Kosaku Murakami Speakers bureau: Eisai Co., Ltd.; Chugai Pharmaceutical Co., Ltd.; Pfizer Inc.; Bristol-Myers Squibb; Mitsubishi Tanabe Pharma Co; UCB Japan Co., Ltd.; Daiichi Sankyo Co., Ltd.; and Astellas Pharma Inc., Consultant of: Eisai Co., Ltd.; Chugai Pharmaceutical Co., Ltd.; Pfizer Inc.; Bristol-Myers Squibb; Mitsubishi Tanabe Pharma Co; UCB Japan Co., Ltd.; Daiichi Sankyo Co., Ltd.; and Astellas Pharma Inc., Koichi Murata Speakers bureau: Eisai Co., Ltd. and Astellas Pharma Inc., Consultant of: Eisai Co., Ltd. and Astellas Pharma Inc., Kohei Nishitani Grant/research support from: Asahi-Kasei Pharma., Ryu Watanabe Speakers bureau: Mitsubishi Tanabe Pharma Co; Pfizer Inc.; Sanofi S.A.; AbbVie GK; Asahi Kasei Pharma; Eisai Co., Ltd.; Eli Lilly and Company; Bristol-Myers Squibb; and Janssen Pharmaceutical K.K., Teruhide Koyama: None declared, Ritei Uehara: None declared, Masao Tanaka Speakers bureau: AbbVie GK, Asahi Kasei Pharma., Astellas Pharma Inc., Ayumi Pharmaceutical Co., Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Eli Lilly Japan K.K., Janssen Pharmaceutical K.K., Mitsubishi Tanabe Pharma Co., Novartis Pharma K.K., Pfizer Inc., Taisyo Pharma., Ltd., UCB Japan Co., Ltd., Grant/research support from: AbbVie GK, Asahi Kasei Pharma., Astellas Pharma Inc., Ayumi Pharmaceutical Co., Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Eli Lilly Japan K.K., Janssen Pharmaceutical K.K., Mitsubishi Tanabe Pharma Co., Novartis Pharma K.K., Pfizer Inc., Taisyo Pharma., Ltd., UCB Japan Co., Ltd., Hiromu Ito Grant/research support from: Bristol-Myers Squibb, Eisai Co, Taisyo Pharma., and Mochida., Shuichi Matsuda: None declared

Clinical utility of CorVue intrathoracic impedance alert with device-measured physical activity in predicting heart failure events

Cardiac implantable electronic devices (CIEDs) offer heart failure (HF) diagnostic information, including intrathoracic impedance (ITI) or physical activity (PA). However, few studies have evaluated the utility of these parameters measured by CIEDs with CorVue algorithm. The purpose of this study was to investigate the relationship between ITI alerts triggered by the CorVue algorithm and HF development. We also examined the association between device-measured PA and ITI alerts associated with HF development. We retrospectively studied consecutive patients with CIEDs equipped with CorVue algorithm, which were implanted between June 1, 2011 and August 31, 2019. These patients were divided into two groups: patients with decreased ITI followed by the ITI alerts (ITI alert group) and those without the alerts (non-ITI alert group). There were 35 and 14 patients in the ITI and non-ITI alert groups, respectively. A total of 96 ITI alerts were observed. ITI alerts associated with HF development were observed in 21% (20/96); whereas, ITI alerts not associated with HF development were observed in 79% (76/96). Accurate device-measured PA was confirmed in 76 ITI alerts, which consisted of 30 alerts with lower PA and 46 alerts without lower PA. ITI alerts associated with HF development were observed in 30% (9/30) of the alerts with lower PA, whereas observed only in 6.5% (3/46) of the alerts without lower PA. In conclusion, the CorVue ITI alerts indicated a high false-positive rate. However, device-measured PA may be useful to determine whether ITI alerts are associated with HF development or not, which was attributed to the high negative predictive value.

The Number of Larval Molts Is Controlled by Hox in Caterpillars

Animals with exoskeletons molt for further growth. In insects, the number of larval (or nymphal) molts varies inter- and intra-specifically, and it is widely accepted that the variation in the number of larval molts is an adaptive response to diverse environmental conditions.^1-5 However, the molecular mechanism that underlies the variety and plasticity in the number of larval molts is largely unknown. In the silkworm, Bombyx mori, there are strains that molt three, four, or five times, and these numbers are determined by allelic variation at a single autosomal locus, Moltinism (M).^6-9 Here, we demonstrate that the Hox gene Sex combs reduced (Scr) is responsible for the phenotypes of the M locus. Scr is selectively expressed in the larval prothoracic gland (PG), an endocrine organ that produces molting hormones.²Scr represses the biosynthesis of molting hormones in the PG, thereby regulating the incremental increase in body size during each larval instar. Our experiments consistently suggest that the differential expression levels of Scr among the three M alleles result in different growth ratios that ultimately lead to the different number of larval molts. Although the role of Hox genes in conferring segmental identity along the body axis and in molding segment-specific structure later in development has been well established,^10-13 the present study identifies an unexpected role of Hox gene in hormone biosynthesis. This new role means that, in addition to shaping segment-specific morphology, Hox genes also drive the evolution of life history traits by regulating animal physiology.