In vivo evidence for homeostatic regulation of ribosomal protein levels in Drosophila.

The ribosome is a molecular machine essential for protein synthesis, which is composed of approximately 80 different ribosomal proteins (Rps). Studies in yeast and cell culture systems have revealed that the intracellular level of Rps is finely regulated by negative feedback mechanisms or ubiquitin-proteasome system, which prevents over- or under-abundance of Rps in the cell. However, in vivo evidence for the homeostatic regulation of intracellular Rp levels has been poor. Here, using Drosophila genetics, we show that intracellular Rp levels are regulated by proteasomal degradation of excess Rps that are not incorporated into the ribosome. By establishing an EGFP-fused Rp gene system that can monitor endogenously expressed Rp levels, we found that endogenously expressed EGFP-RpS20 or -RpL5 is eliminated from the cell when RpS20 or RpL5 is exogenously expressed. Notably, the level of endogenously expressed Hsp83, a housekeeping gene, was not affected by exogenous expression of Hsp83, suggesting that the strict negative regulation of excess protein is specific for intracellular Rps. Further analyses revealed that the maintenance of cellular Rp levels is not regulated at the transcriptional level but by proteasomal degradation of excess free Rps as a protein quality control mechanism. Our observations provide not only the in vivo evidence for the homeostatic regulation of Rp levels but also a novel genetic strategy to study in vivo regulation of intracellular Rp levels and its role in tissue homeostasis via cell competition.Key words: ribosomal protein, proteasomal degradation, Drosophila.

Middle-segment preserving pancreatectomy: a literature review and case report.

PURPOSE: Middle segment-preserving pancreatectomy (MSPP) is a relatively new parenchymal-sparing surgery that has been introduced as an alternative to total pancreatectomy (TP) for multicentric benign and borderline pancreatic diseases. To date, only 36 cases have been reported in English. METHODS: We reviewed 22 published articles on MSPP and reported an additional case. RESULTS: Our patient was a 49-year-old Japanese man diagnosed with Zollinger-Elison syndrome (ZES) caused by duodenal and pancreatic gastrinoma associated with multiple endocrine neoplasia syndrome type 1. We avoided TP and chose MSPP as the operative technique due to his relatively young age. The patient developed a grade B postoperative pancreatic fistula (POPF), which improved with conservative treatment. He was discharged without further treatment. To date, no tumor has recurred, and pancreatic function seems to be maintained. According to a literature review, the morbidity rate of MSPP is as high as 54%, mainly due to the high incidence of POPF (32%). In contrast, there was no perioperative mortality, and postoperative pancreatic function was comparable to that after conventional pancreatectomy. CONCLUSIONS: Despite the high incidence of POPF, MSPP appears to be safe, with low perioperative mortality and good postoperative pancreatic sufficiency.

JNK and Yorkie drive tumor malignancy by inducing L-amino acid transporter 1 in Drosophila.

Identifying a common oncogenesis pathway among tumors with different oncogenic mutations is critical for developing anti-cancer strategies. Here, we performed transcriptome analyses on two different models of Drosophila malignant tumors caused by Ras activation with cell polarity defects (RasV12/scrib-/-) or by microRNA bantam overexpression with endocytic defects (bantam/rab5-/-), followed by an RNAi screen for genes commonly essential for tumor growth and malignancy. We identified that Juvenile hormone Inducible-21 (JhI-21), a Drosophila homolog of the L-amino acid transporter 1 (LAT1), is upregulated in these malignant tumors with different oncogenic mutations and knocking down of JhI-21 strongly blocked their growth and invasion. JhI-21 expression was induced by simultaneous activation of c-Jun N-terminal kinase (JNK) and Yorkie (Yki) in these tumors and thereby contributed to tumor growth and progression by activating the mTOR-S6 pathway. Pharmacological inhibition of LAT1 activity in Drosophila larvae significantly suppressed growth of RasV12/scrib-/- tumors. Intriguingly, LAT1 inhibitory drugs did not suppress growth of bantam/rab5-/- tumors and overexpression of bantam rendered RasV12/scrib-/- tumors unresponsive to LAT1 inhibitors. Further analyses with RNA sequencing of bantam-expressing clones followed by an RNAi screen suggested that bantam induces drug resistance against LAT1 inhibitors via downregulation of the TMEM135-like gene CG31157. Our observations unveil an evolutionarily conserved role of LAT1 induction in driving Drosophila tumor malignancy and provide a powerful genetic model for studying cancer progression and drug resistance.

Cell competition is driven by Xrp1-mediated phosphorylation of eukaryotic initiation factor 2α.

Cell competition is a context-dependent cell elimination via cell-cell interaction whereby unfit cells ('losers') are eliminated from the tissue when confronted with fitter cells ('winners'). Despite extensive studies, the mechanism that drives loser's death and its physiological triggers remained elusive. Here, through a genetic screen in Drosophila, we find that endoplasmic reticulum (ER) stress causes cell competition. Mechanistically, ER stress upregulates the bZIP transcription factor Xrp1, which promotes phosphorylation of the eukaryotic translation initiation factor eIF2α via the kinase PERK, leading to cell elimination. Surprisingly, our genetic data show that different cell competition triggers such as ribosomal protein mutations or RNA helicase Hel25E mutations converge on upregulation of Xrp1, which leads to phosphorylation of eIF2α and thus causes reduction in global protein synthesis and apoptosis when confronted with wild-type cells. These findings not only uncover a core pathway of cell competition but also open the way to understanding the physiological triggers of cell competition.

A case of cutaneous syncytial myoepithelioma with extensive adipocytic metaplasia: Usefulness of EWSR1-PBX3 gene fusion analysis.

Cutaneous syncytial myoepithelioma (CSM) is a recently recognized variant of myoepithelioma characterized by an intradermal syncytial proliferation of spindled, ovoid, and histiocytoid cells. Immunohistochemically, tumor cells usually show strong expression of S-100 protein and epithelial membrane antigen (EMA). Here we report a case of CSM in the thigh of a 51-year-old Japanese woman. Histopathological findings showed a sheet-like growth of ovoid cells and histiocytoid cells with an eosinophilic syncytial cytoplasm, and adipocytic metaplasia was widely observed in the tumor. Immunohistochemical staining revealed a diffuse, strong pattern for EMA, smooth muscle actin (SMA), and HHF35, and variable expression of S-100 protein and p63 in ovoid and histiocytoid cells without significant mitotic figures or pleomorphism. In addition, EWSR1-PBX3 gene fusion, which is characteristic of CSM, was observed in the tumor. Based on these findings, we diagnosed the patient as having CSM. Our case shows that CSM can exhibit extensive adipocytic metaplasia, which could make its histopathological diagnosis challenging.

Indices for the evaluation of glandular dose heterogeneity in full-field digital mammography.

This study aims to evaluate the indices of glandular dose heterogeneity in full-field digital mammography. The distributions of GD in a breast phantom with a skin layer of 4 mm were determined using the Monte Carlo method with simulated x-ray fluence spectra. First, the GD to air kerma (GD/Kair) volume histogram was obtained from the GD distributions, which were indicated by the glandular volume (%) as a function of GD/Kair. The GD indices, namely, the maximum glandular dose (GD2%) and glandular volume percentage (%) receiving at least the mean glandular dose (MGD) (VMGD) were calculated from the GD/Kairvolume histogram. Next, the scatter plots of GD2%/MGD andVMGDwere drawn as functions of the normalised mean glandular dose (DgN). Finally, (GD2%)iand (VMGD)iwere obtained from the relationship between the GD indices and DgN for 596 clinical irradiation cases based on individual irradiation conditions. The values of GD2%/MGD were more affected by breast thickness than glandularity and tube voltage, and they decreased according to the power law of DgN for all the target/filter combinations. The values ofVMGDwere proportional to DgN and decreased with increase in the compressed breast thickness. The values of (MGD)iand (GD2%)ifor 596 clinical irradiation cases were estimated to range from 0.6-3.0 mGy to 1.1-7.0 mGy, respectively, and (VMGD)iwas in the range 32%-48%. (GD2%)iand (VMGD)iare mainly affected by breast thickness. These indices are useful for the evaluation of glandular dose heterogeneity in mammography.

Mitochondrial defect drives non-autonomous tumour progression through Hippo signalling in Drosophila.

Mitochondrial respiratory function is frequently impaired in human cancers. However, the mechanisms by which mitochondrial dysfunction contributes to tumour progression remain elusive. Here we show in Drosophila imaginal epithelium that defects in mitochondrial function potently induce tumour progression of surrounding tissue in conjunction with oncogenic Ras. Our data show that Ras activation and mitochondrial dysfunction cooperatively stimulate production of reactive oxygen species, which causes activation of c-Jun amino (N)-terminal kinase (JNK) signalling. JNK cooperates with oncogenic Ras to inactivate the Hippo pathway, leading to upregulation of its targets Unpaired (an interleukin-6 homologue) and Wingless (a Wnt homologue). Mitochondrial dysfunction in Ras-activated cells further cooperates with Ras signalling in neighbouring cells with normal mitochondrial function, causing benign tumours to exhibit metastatic behaviour. Our findings provide a mechanistic basis for interclonal tumour progression driven by mitochondrial dysfunction and oncogenic Ras.

A unique case of a typical pancreatic ductal adenocarcinoma that initially presented with a cystic component but underwent morphological changes.

A 66-year-old man was initially suspected of having a microcystic serous cystic neoplasm based on magnetic resonance imaging findings of a multifocal mass measuring 46 mm in the pancreatic head, with a cystic component showing a high signal on T2-weighted images. The tumor marker levels were within normal limits. However, contrast-enhanced computed tomography revealed thick cyst walls with delayed staining, which was atypical for serous cystic neoplasms; therefore, the patient was followed up closely. Twenty-two months later, the delayed contrast area was enlarged, carbohydrate antigen 19-9 levels were elevated, and 18 F-fluorodeoxyglucose-positron emission tomography revealed increased accumulation, indicating a potentially malignant lesion. Pancreatoduodenectomy was performed and histopathological examination confirmed the diagnosis of normal-type pancreatic carcinoma with predominantly poorly differentiated cells. Based on the pathological findings and a literature review, it is highly likely that this case represents pancreatic ductal adenocarcinoma with a cystic structure from the beginning. While distinguishing pancreatic ductal adenocarcinoma from other pancreatic cystic tumors, such as serous cystic neoplasms, is critical owing to differing treatments and prognoses, caution is warranted as they may exhibit similar imaging features, as observed in our patient.

Brexpiprazole: A new option in treating agitation in Alzheimer's dementia-Insights from transgenic mouse models.

AIM: Brexpiprazole is the first FDA-approved treatment for agitation associated with dementia due to Alzheimer's disease. Agitation in Alzheimer's dementia (AAD) occurs in high prevalence and is a great burden for patients and caregivers. Efficacy, safety, and tolerability of brexpiprazole were demonstrated in the AAD clinical trials. To demonstrate the agitation-ameliorating effect of brexpiprazole in animals, we evaluated brexpiprazole in two AAD mouse models. METHODS: The resident-intruder test was conducted in 5- to 6-month-old Tg2576 mice, given vehicle or brexpiprazole (0.01 or 0.03 mg/kg) orally 1 h before the test. Locomotor activity was measured in 6-month-old APPSL-Tg mice given vehicle or brexpiprazole (0.01 or 0.03 mg/kg) orally the evening before the start of locomotor measurement for 3 days. RESULTS: In the resident-intruder test, Tg2576 mice showed significantly higher attack number and shorter latency to first attack compared to non-Tg mice. In the Tg mice, brexpiprazole treatment (0.03 mg/kg) significantly delayed the latency to first attack and showed a trend toward a decrease in attack number. APPSL-Tg mice (≧6 months old) showed significantly higher locomotion during dark period Phase II (Zeitgeber time [ZT] 16-20) and Phase III (ZT20-24) compared to non-Tg mice, correlating with the clinical observations of late afternoon agitation in Alzheimer's disease. Brexpiprazole treatment (0.01 and 0.03 mg/kg) significantly decreased hyperlocomotion during the Phase III in APPSL-Tg mice. CONCLUSION: The suppression of attack behavior and the reduction of nocturnal hyperlocomotion in these Tg mice may be indicative of the therapeutic effect of brexpiprazole on AAD, as demonstrated in the clinical trials.

Pancreaticoduodenectomy after bilirubin adsorption for distal cholangiocarcinoma with severe obstructive jaundice refractory to repeat preoperative endoscopic biliary drainage: a case report.

The necessity of biliary drainage before pancreaticoduodenectomy remains controversial in cases involving malignant obstructive jaundice; however, the benefits of biliary drainage have been reported in cases with severe hyperbilirubinemia. Herein, we present the case of a 61-year-old man suffering from jaundice due to distal cholangiocarcinoma. In this case, obstructive jaundice was refractory to repeat endoscopic drainage and bilirubin adsorption. Hyperbilirubinemia persisted despite successful implementation of biliary endoscopic sphincterotomy and two rounds of plastic stent placements. Stent occlusion and migration were unlikely and oral cholagogues proved ineffective. Owing to the patient's surgical candidacy and his aversion to nasobiliary drainage due to discomfort, bilirubin adsorption was introduced as an alternative therapeutic intervention. Following repeated adsorption sessions, a gradual decline in serum total bilirubin levels was observed and pancreaticoduodenectomy was scheduled. The patient successfully underwent pancreaticoduodenectomy with portal vein resection and reconstruction and D2 lymph node dissection. After the surgery, the serum bilirubin levels gradually decreased and the patient remained alive, with no recurrence at 26 months postoperatively. Therefore, this case highlights the feasibility and safety of performing pancreaticoduodenectomy in patients with severe, refractory jaundice who have not responded to repeated endoscopic interventions and have partially responded to bilirubin adsorption.

A deazariboflavin chromophore kinetically stabilizes reduced FAD state in a bifunctional cryptochrome.

An animal-like cryptochrome derived from Chlamydomonas reinhardtii (CraCRY) is a bifunctional flavoenzyme harboring flavin adenine dinucleotide (FAD) as a photoreceptive/catalytic center and functions both in the regulation of gene transcription and the repair of UV-induced DNA lesions in a light-dependent manner, using different FAD redox states. To address how CraCRY stabilizes the physiologically relevant redox state of FAD, we investigated the thermodynamic and kinetic stability of the two-electron reduced anionic FAD state (FADH-) in CraCRY and related (6-4) photolyases. The thermodynamic stability of FADH- remained almost the same compared to that of all tested proteins. However, the kinetic stability of FADH- varied remarkably depending on the local structure of the secondary pocket, where an auxiliary chromophore, 8-hydroxy-7,8-didemethyl-5-deazariboflavin (8-HDF), can be accommodated. The observed effect of 8-HDF uptake on the enhancement of the kinetic stability of FADH- suggests an essential role of 8-HDF in the bifunctionality of CraCRY.

Multivisceral resection for primary pancreatic signet ring cell carcinoma.

Primary pancreatic signet ring cell carcinoma (PPSRCC) is a rare and aggressive tumor with poor prognosis. Here, we report a case of PPSRCC treated with curative surgery. A 49-year-old man presented with right mid-abdominal pain. Imaging tests showed a 3.6 cm tumor extending around the head of the pancreas, the second portion of the duodenum, and the retroperitoneum. Involvement of the right proximal ureter resulted in moderate right hydronephrosis. A subsequent tumor biopsy revealed suspected pancreatic adenocarcinoma. No apparent lymph node or remote metastases were observed. The tumor was considered resectable, and radical pancreaticoduodenectomy was planned. Pancreaticoduodenectomy, right nephroureterectomy, and right hemicolectomy were conducted to resect the tumor en bloc. Final pathology revealed a poorly differentiated ductal adenocarcinoma of the pancreas with signet ring cells infiltrating the right ureter and transverse mesocolon (pT3N0M0, stage IIA, according to UICC for International Cancer Control TNM classification). The postoperative course was uneventful, and oral fluoropyrimidine (S-1) was administered as adjuvant chemotherapy for 1 year. At the 16-month follow-up, the patient was alive without any evidence of recurrence. Pancreaticoduodenectomy with right hemicolectomy and right nephroureterectomy was performed for curative resection of PPSRCC infiltrating the transverse mesocolon and right ureter.

Hepatectomy for liver metastases from cervical cancer with portal vein tumor thrombosis: a case report.

The prognosis of patients with liver metastasis of cervical cancer is poor with an extremely short survival period, and there have been no reports of cervical cancer complicated by portal vein tumor thrombosis (PVTT). We report a case of cervical cancer developing liver metastasis with PVTT. A 49-year-old woman developed liver metastasis from cervical cancer with PVTT. The primary tumor was locally controlled with multidisciplinary treatment, including systemic therapy, surgical resection, and radiation. However, her follow-up abdominal computed tomography results showed two irregular tumors in the liver's segments 2 and 6. From the latter lesion, a low-density filling defect extended to the posterior branch of the portal vein, suggesting PVTT. Hepatectomy of the two metastases was performed to prevent portal vein obstruction during subsequent chemotherapy. Pathological analysis revealed metastatic squamous cell carcinoma from cervical cancer that developed a tumor thrombus at the posterior branch of the portal vein. The patient received adjuvant chemotherapy, but died 10 months after surgery for recurrent liver metastasis. We present the first case of liver resection for liver metastasis from cervical cancer with PVTT. Although cervical cancer with PVTT is associated with a poor prognosis, surgical resection is a feasible option for preventing portal vein obstruction during subsequent chemotherapy.

Liver resection in a patient with persistent positive PCR test for coronavirus disease 2019 (COVID-19): a case report.

BACKGROUND: The perioperative mortality rate is high in patients with coronavirus disease 2019 (COVID-19), and infection control measures for medical care providers must be considered. Therefore, the timing for surgery in patients recovering from COVID-19 is difficult. CASE PRESENTATION: A 65-year-old man was admitted to a hospital with a diagnosis of moderate COVID-19. He was transferred to our hospital because of risk factors, including heavy smoking history, type 2 diabetes mellitus, and obesity (BMI 34). Vital signs on admission were a temperature of 36.1 °C, oxygen saturation > 95% at rest, and 94% on exertion with 3 L/min of oxygen. Chest computed tomography (CT) showed bilateral ground-glass opacities, predominantly in the lower lungs. Contrast-enhanced abdominal CT incidentally revealed a liver tumor with a diameter of 80 mm adjacent to the middle hepatic vein, which was diagnosed as hepatocellular carcinoma (HCC). After being administered baricitinib, remdesivir, dexamethasone, and heparin, the patient's COVID-19 pneumonia improved, his oxygen demand resolved, and he was discharged on day 13. Furthermore, the patient was initially scheduled for hepatectomy 8 weeks after the onset of COVID-19 following a discussion with the infection control team. However, 8 weeks after the onset of illness, a polymerase chain reaction (PCR) test was performed on nasopharyngeal swab fluid, which was observed to be positive. The positive results persisted till 10 and 11 weeks after onset. Both Ct values were high (≥ 31) out of 45 cycles, with no subjective symptoms. Since we determined that he was no longer contagious, surgery was performed 12 weeks after the onset of COVID-19. Notably, medical staff wearing personal protective equipment performed extended anatomical resection of the liver segment 8 ventral area in a negative-pressure room. The patient had a good postoperative course, with no major complications, including respiratory complications, and was discharged on postoperative day 14. Finally, none of the staff members was infected with COVID-19. CONCLUSIONS: We reported a case regarding the timing of surgery on a patient with persistently positive PCR test results after COVID-19, along with a literature review.

[Construction and Analysis of a Digital Mammography Database: Analysis of Breast Compression Pressures at Four Facilities].

We analyzed the compression pressures in 2772 mammography images of 807 patients acquired by digital mammography equipment at four facilities. The analysis included the average compression pressure at all facilities, difference in compression pressure at each facility, differences between the pressures used by radiological technologists in the same facility, and difference attributed to the breast structure. We also analyzed the effects of the compression pressure on the breast thickness and mean glandular dose (MGD) at each facility. The median values of the compression pressure and breast thickness for the 2772 images at all facilities were 86.5 N and 43 mm, respectively. The compression pressures differed among the institutions. The maximum difference in the median pressures among the four facilities was 38.6 N, while the difference in the breast thickness was 6 mm. The radiological technologists working at the same facility used almost the same compression pressure. However, differences between the compression pressures used by different radiological technologists were observed. The compression pressure in a dense breast was smaller than that in a non-dense breast. The difference in the compression pressure affected the breast thickness and MGD. The results of this analysis could be utilized for an optimal imaging in future digital mammography.

GDE2-RECK controls ADAM10 α-secretase-mediated cleavage of amyloid precursor protein.

A disintegrin and metalloprotease 10 (ADAM10) is the α-secretase for amyloid precursor protein (APP). ADAM10 cleaves APP to generate neuroprotective soluble APPα (sAPPα), which precludes the generation of Aß, a defining feature of Alzheimer's disease (AD) pathophysiology. Reduced ADAM10 activity is implicated in AD, but the mechanisms mediating ADAM10 modulation are unclear. We find that the plasma membrane enzyme glycerophosphodiester phosphodiesterase 2 (GDE2) stimulates ADAM10 APP cleavage by shedding and inactivating reversion-inducing cysteine-rich protein with Kazal motifs (RECK), a glycosylphosphatidylinositol (GPI)-anchored inhibitor of ADAM10. In AD, membrane-tethered RECK is highly elevated and GDE2 is abnormally sequestered inside neurons. Genetic ablation of GDE2 phenocopies increased membrane RECK in AD, which is causal for reduced sAPPα, increased Aß, and synaptic protein loss. RECK reduction restores the balance of APP processing and rescues synaptic protein deficits. These studies identify GDE2 control of RECK surface activity as essential for ADAM10 α-secretase function and physiological APP processing. Moreover, our results suggest the involvement of the GDE2-RECK-ADAM10 pathway in AD pathophysiology and highlight RECK as a potential target for therapeutic development.

DNA-protein crosslink formation by endogenous aldehydes and AP sites.

Covalent binding between proteins and a DNA strand produces DNA-protein crosslinks (DPC). DPC are one of the most deleterious types of DNA damage, leading to the blockage of DNA replication and transcription. Both DNA lesions and endogenous products with carbonyl functional groups can produce DPC in genomic DNA under normal physiological conditions. For example, formaldehyde, the most abundant endogenous human carcinogen, and apurinic/apyrimidinic (AP) sites, the most common type of endogenous DNA lesions, has been shown to crosslink proteins and/or DNA through their carbonyl functional groups. Unfortunately, compared to other types of DNA damage, DPC have been less studied and understood. However, a recent advancement has allowed researchers to determine accurate yields of various DNA lesions including formaldehyde-derived DPC with high sensitivity and specificity, paving the way for new developments in this field of research. Here, we review the current literature and remaining unanswered questions on DPC formation by endogenous formaldehyde and various aldehydic 2-deoxyribose lesions.

Cell Competition Is Driven by Autophagy.

Cell competition is a quality control process that selectively eliminates unfit cells from the growing tissue via cell-cell interaction. Despite extensive mechanistic studies, the mechanism by which cell elimination is triggered has been elusive. Here, through a genetic screen in Drosophila, we discover that V-ATPase, an essential factor for autophagy, is required for triggering cell competition. Strikingly, autophagy is specifically elevated in prospective "loser" cells nearby wild-type "winner" cells, and blocking autophagy in loser cells abolishes their elimination. Mechanistically, elevated autophagy upregulates a proapoptotic gene hid through NFκB, and the elevated hid cooperates with JNK signaling to effectively induce loser's death. Crucially, this mechanism generally applies to cell competition caused by differences in protein synthesis between cells. Our findings establish a common mechanism of cell competition whereby cells with higher protein synthesis induce autophagy in their neighboring cells, leading to elimination of unfit cells.

A GH family 28 endo-polygalacturonase from the brown-rot fungus Fomitopsis palustris: Purification, gene cloning, enzymatic characterization and effects of oxalate.

Brown-rot fungi are the wood-decay basidiomycetes and have ability to break down plant cell wall carbohydrates. It has been suggested that degradation of pectin is important for the initial stages of brown rot. We purified an endo-polygalacturonase (FpPG28A) from the brown-rot fungus Fomitopsis palustris, analysis of the predicted amino acid sequence indicated that FpPG28A belongs to GH family 28. The highest activity of purified FpPG28A was observed at 60 °C in 50 mM sodium acetate buffer (pH 5.0); this activity was highly specific for polygalacturonic acid chains. However, calcium polygalacturonate gel was not degraded by FpPG28A under those optimal conditions. We observed that calcium polygalacturonate gel was readily degraded by the enzyme in the oxalate buffer. Furthermore, the thermostability of FpPG28A was elevated in oxalate buffer at pH 3.0. These results indicated that oxalate has an important role in the degradation of woody pectin by FpPG28A.