Efficacy of dupilumab for severe chronic rhinosinusitis with nasal polyps and asthma: A prospective study.

BACKGROUND: Dupilumab exerts clinical effects, including improved sinus opacification, olfactory function, and quality of life, in patients with severe chronic rhinosinusitis with nasal polyps (CRSwNPs). Meanwhile, only a few studies have reported its effects on nasal airway resistance and olfactory function, particularly in the Japanese population. Predictors of response remain unclear. OBJECTIVE: To assess the comprehensive efficacy and therapeutic response to dupilumab in patients with severe CRSwNP with comorbid asthma. METHODS: In 16 adult patients with severe CRSwNP with comorbid asthma, the efficacy of 48-week dupilumab treatment, including olfactory function measured by a T&T olfactometer, nasal airway resistance measured by rhinomanometry, nasal polyp score, Lund-Mackay computed tomography score, and 22-item Sinonasal Outcome Test (SNOT-22), was assessed. Regarding asthma, the annualized rate of exacerbations, 7-item Asthma Control Questionnaire (ACQ-7), and spirometry were assessed. Treatment responsiveness was analyzed. RESULTS: With 48-week dupilumab treatment, olfactory function, nasal airway resistance, nasal polyp score, Lund-Mackay computed tomography score, and SNOT-22 scores improved significantly. Regarding comorbid asthma, the annualized rate of exacerbations decreased, and ACQ-7 scores and lung function improved significantly. According to the European Position Paper on Rhinosinusitis and Nasal Polyps 2020/European Forum for Research and Education in Allergy and Airway Diseases criteria, 15 patients (94%) were moderate-to-excellent responders at 48 weeks of treatment. Patients with higher SNOT-22 scores, ACQ-7 scores, the rate of asthma exacerbations in the previous year, and blood eosinophil counts benefited more from the treatment. CONCLUSION: Dupilumab improved upper and lower airway outcomes especially in patients with severe CRSwNP with comorbid, poorly controlled asthma. TRIAL REGISTRATION: UMIN Clinical Trials Registry: UMIN000038669.

A rare case of a huge malignant pleural mesothelioma presenting in the posterior mediastinum.

We report a case of a 69-year-old woman with pleural mesothelioma presenting in the posterior mediastinum with a maximum diameter of 25 cm. She had a chronic cough and a pleural effusion was noted on chest X-ray. The examination of the effusion showed high hyaluronic acid levels, and mesothelioma was suspected. A chest computed tomography scan showed a huge mediastinal mass, which caused rapid progression of respiratory failure and compression of the heart. Sufficient tissue samples could not be obtained before death. The patient died approximately 1 month after the initial visit, and a pathological autopsy was performed. The diagnosis of malignant pleural mesothelioma was made. Malignant pleural mesothelioma with a huge posterior mediastinal mass such as in this case is considerably rare; however, it is a rapidly progressing form of the disease and is reported here as an important differential diagnosis for mediastinal tumours.

Prevalence and clinical relevance of comorbid pertussis infection in adult patients with asthma: A prospective, cross-sectional study.

BACKGROUND: Viral or atypical bacterial respiratory infections are involved in the new development and the pathogenesis of asthma. Though an association between pertussis and asthma has been expected, few studies have reported it consistently. We assessed the prevalence and clinical relevance of pertussis infection in adult patients with asthma. METHODS: In this prospective, cross-sectional study, newly referred, adult patients with asthma (n = 107) and with non-asthmatic subacute/chronic cough (n = 31) were enrolled. The prevalence of pertussis in patients with asthma and in those with non-asthmatic subacute/chronic cough was assessed. Next, the prevalence of newly diagnosed asthma was compared between asthmatic patients with and without pertussis. Finally, demographic characteristics of patients, blood test results, pulmonary function test results, and questionnaire scores were compared between the two patient groups. RESULTS: The prevalence of pertussis infection was significantly higher in patients with asthma than in those with non-asthmatic subacute/chronic cough (36% vs 10%; P = 0.004). The prevalence of newly diagnosed asthma was significantly higher in asthmatic patients with pertussis than in those without (74.4% vs 50.0%; P = 0.014). The physical, psychological, and total scores of the Leicester Cough Questionnaire were significantly lower in asthmatic patients with pertussis than in those without (all P < 0.05). The acid-reflux, dyspeptic, and total scores of the Frequency Scale for Symptoms of Gastroesophageal Reflux Disease (GERD) (FSSG) were significantly higher in asthmatic patients with pertussis than in those without (all P ≤ 0.05). The FSSG acid-reflux score was negatively correlated with the cough-specific quality of life (QOL) score only in asthmatic patients with pertussis (rho = -0.68, P = 0.01). CONCLUSIONS: The prevalence of pertussis infection was significantly higher in adult patients with asthma than in those with non-asthmatic subacute/chronic cough. In patients with asthma, comorbid pertussis infection may play a role in newly diagnosed asthma and may contribute to impaired cough-specific QOL partly due to worsening acid-reflux symptoms of GERD.

Green/red light-sensing mechanism in the chromatic acclimation photosensor.

Certain cyanobacteria alter their photosynthetic light absorption between green and red, a phenomenon called complementary chromatic acclimation. The acclimation is regulated by a cyanobacteriochrome-class photosensor that reversibly photoconverts between green-absorbing (Pg) and red-absorbing (Pr) states. Here, we elucidated the structural basis of the green/red photocycle. In the Pg state, the bilin chromophore adopted the extended C15-Z,anti structure within a hydrophobic pocket. Upon photoconversion to the Pr state, the bilin is isomerized to the cyclic C15-E,syn structure, forming a water channel in the pocket. The solvation/desolvation of the bilin causes changes in the protonation state and the stability of π-conjugation at the B ring, leading to a large absorption shift. These results advance our understanding of the enormous spectral diversity of the phytochrome superfamily.

The safety of perioperative antiplatelet continuation without selection biases in microsurgical decompression surgery for single level lumbar spinal stenosis and lumbar disc herniotomy.

PURPOSE: Each institution or physician has to decide on an individual basis whether to continue or discontinue antiplatelet (AP) therapy before spinal surgery. The purpose of this study was to determine if perioperative AP continuation is safe during single-level microsurgical decompression (MSD) for treating lumbar spinal stenosis (LSS) and lumbar disc hernia (LDH) without selection bias. METHODS: Patients who underwent single-level MSD for LSS and LDH between April 2018 to December 2022 at our institute were included in this retrospective study. We collected data regarding baseline characteristics, medical history/comorbidities, epidural hematoma (EDH) volume, reoperation for EDH, differences between preoperative and one-day postoperative blood cell counts (ΔRBC), hemoglobin (ΔHGB), and hematocrits (ΔHCT), and perioperative thromboembolic complications. Patients were divided into two groups: the AP continuation group received AP treatment before surgery and the control group did not receive antiplatelet medication before surgery. Propensity scores for receiving AP agents were calculated, with one-to-one matching of estimated propensity scores to adjust for patient baseline characteristics and past histories. Reoperation for EDH, EDH volume, ΔRBC, ΔHGB, ΔHCT, and perioperative thromboembolic complications were compared between the groups. RESULTS: The 303 enrolled patients included 41 patients in the AP continuation group. After propensity score matching, the rate of reoperation for EDH, the EDH volume, ΔRBC, ΔHGB, ΔHCT, and perioperative thromboembolic complication rates were not significantly different between the groups. CONCLUSION: Perioperative AP continuation is safe for single-level lumbar MSD, even without biases.

Structure and Dynamics of Drk-SH2 Domain and Its Site-Specific Interaction with Sev Receptor Tyrosine Kinase.

The Drosophila downstream receptor kinase (Drk), a homologue of human GRB2, participates in the signal transduction from the extracellular to the intracellular environment. Drk receives signals through the interaction of its Src homology 2 (SH2) domain with the phosphorylated tyrosine residue in the receptor tyrosine kinases (RTKs). Here, we present the solution NMR structure of the SH2 domain of Drk (Drk-SH2), which was determined in the presence of a phosphotyrosine (pY)-containing peptide derived from a receptor tyrosine kinase, Sevenless (Sev). The solution structure of Drk-SH2 possess a common SH2 domain architecture, consisting of three ß strands imposed between two α helices. Additionally, we interpret the site-specific interactions of the Drk-SH2 domain with the pY-containing peptide through NMR titration experiments. The dynamics of Drk-SH2 were also analysed through NMR-relaxation experiments as well as the molecular dynamic simulation. The docking simulations of the pY-containing peptide onto the protein surface of Drk-SH2 provided the orientation of the peptide, which showed a good agreement with the analysis of the SH2 domain of GRB2.

Comorbid functional dyspepsia reflects IL-33-mediated airway neuronal dysfunction in asthma.

BACKGROUND: Neuronal dysfunction is implicated in the pathophysiology of asthma and functional dyspepsia (FD). However, the relationship between these diseases remains unclear. OBJECTIVE: This study aimed to clarify the clinical implications of comorbid FD in asthma and to explore the unified pathway between asthma and FD by focusing on airway neuronal dysfunction. METHODS: Clinical indices and biomarkers, including capsaicin cough sensitivity (C-CS), were compared between patients with asthma with and without FD. C-CS was determined on the basis of capsaicin concentration that induced at least 2 coughs (C2) or 5 coughs (C5). Additionally, the associations of airway inflammation with airway innervation and gastrointestinal motility were evaluated in mouse models of type 2 airway inflammation. RESULTS: Patients with asthma with FD had worse asthma control and cough severity and lower C2 and C5 thresholds than those without FD. The severity of FD symptoms was negatively correlated with C2 and C5 thresholds. FD and poor asthma control were predictors of heightened C-CS (defined as C5 ≤ 2.44 µmol) in asthma. A mouse model of papain-induced airway inflammation developed airway hyperinnervation and gastrointestinal dysmotility, and both pathologies were ameliorated by an anti-IL-33 antibody. Moreover, papain-induced gastrointestinal dysmotility was mitigated by silencing the airway sensory neurons using QX-314, a sodium channel blocker. Furthermore, sputum IL-33 levels were significantly elevated in patients with asthma with FD or heightened C-CS compared to their counterparts. CONCLUSION: FD is significantly associated with airway neuronal dysfunction in asthma. IL-33-mediated airway neuronal dysfunction may contribute to the interaction between asthma and FD.

Pulmonary function and chest CT abnormalities 3 months after discharge from COVID-19, 2020-2021: A nation-wide multicenter prospective cohort study from the Japanese respiratory society.

BACKGROUND: No comprehensive analysis of the pulmonary sequelae of coronavirus disease 2019 (COVID-19) in Japan based on respiratory function tests and chest computed tomography (CT) has been reported. We evaluated post-COVID-19 conditions, especially focusing on pulmonary sequelae assessed by pulmonary function tests and chest CT. METHODS: For this prospective cohort study, we enrolled 1069 patients who presented pneumonia at the time of admission in 55 hospitals from February 2020 to September 2021. Disease severity was classified as moderateⅠ, moderate II, and severe, defined primarily according to the degree of respiratory failure. The data on post-COVID-19 conditions over 12 months, pulmonary function, and chest CT findings at 3 months were evaluated in this study. Additionally, the impact of COVID-19 severity on pulmonary sequelae, such as impaired diffusion capacity, restrictive pattern, and CT abnormalities, was also evaluated. RESULTS: The most frequently reported post-COVID-19 conditions at 3 months after COVID-19 were muscle weakness, dyspnea, and fatigue (48.4%, 29.0%, and 24.7%, respectively). The frequency of symptoms gradually decreased over subsequent months. In pulmonary function tests at 3 months, the incidence of impaired diffusion capacity and restrictive pattern increased depending on disease severity. There also were differences in the presence of chest CT abnormalities at the 3 months, which was markedly correlated with the severity. CONCLUSION: We reported a comprehensive analysis of post-COVID-19 condition, pulmonary function, and chest CT abnormalities in Japanese patients with COVID-19. The findings of this study will serve as valuable reference data for future post-COVID-19 condition research in Japan.

Structural and Functional Analysis of the Amorphous Calcium Carbonate-Binding Protein Paramyosin in the Shell of the Pearl Oyster, Pinctada fucata.

Amorphous calcium carbonate (ACC) is an important precursor phase for the formation of aragonite crystals in the shells of Pinctada fucata. To identify the ACC-binding protein in the inner aragonite layer of the shell, extracts from the shell were used in the ACC-binding experiments. Semiquantitative analyses using liquid chromatography-mass spectrometry revealed that paramyosin was strongly associated with ACC in the shell. We discovered that paramyosin, a major component of the adductor muscle, was included in the myostracum, which is the microstructure of the shell attached to the adductor muscle. Purified paramyosin accumulates calcium carbonate and induces the prism structure of aragonite crystals, which is related to the morphology of prism aragonite crystals in the myostracum. Nuclear magnetic resonance measurements revealed that the Glu-rich region was bound to ACC. Activity of the Glu-rich region was stronger than that of the Asp-rich region. These results suggest that paramyosin in the adductor muscle is involved in the formation of aragonite prisms in the myostracum.

Microvascular Decompression for Trigeminal Neuralgia with Complicated Offending Vessel Involving Trigeminocerebellar Artery: 2-Dimensional Operative Video.

Microvascular decompression (MVD) is a well-established and definitive treatment option for trigeminal neuralgia (TN).1 However, complex vascular geometry and numerous offending vessels make it difficult to perform nerve decompression in certain cases.2 The trigeminocerebellar artery (TCA) is a unique branch of the basilar artery. The vessel is named the TCA because it supplies both the trigeminal nerve root and the cerebellar hemisphere.3 This anatomical variant may increase the risk of neurovascular compression in the trigeminal nerve. We present the case of a 74-year-old man with left TN in whom a TCA was one of the responsible compression vessels. Preoperative images revealed the ipsilateral anterior inferior cerebellar artery, well-developed TCA, and superior cerebellar artery, wherein these branches were all suspected to be involved in trigeminal nerve compression. In MVD, 3 arteries were suspected to compress the trigeminal nerve in 5 sites, and all of them needed to be meticulously dissected from the nerve root and decompressed. Moreover, 2 of them branched many short perforators to the brainstem. Three decompression procedures (transposition to the dura, transposition to the brain, and interposition) were performed to decompress the trigeminal nerve. Postoperatively, TN was completely resolved immediately. MVD for TN could be difficult to perform in cases with TCA, as in the present case, and rigorous procedures were required intraoperatively.

Efficacy of dupilumab for airway hypersecretion and airway wall thickening in patients with moderate-to-severe asthma: A prospective, observational study.

BACKGROUND: Dupilumab has clinical effects in patients with moderate-to-severe asthma. When considering interleukin (IL)-4 and IL-13 signaling, effects of dupilumab on airway mucus hypersecretion and airway remodeling are expected, but they have been reported in only a few short-term studies. Its efficacy for airway hyperresponsiveness (AHR) remains unknown. We comprehensively assessed the efficacy of dupilumab, especially for subjective and objective measures of airway mucus hypersecretion and airway dimensions in moderate-to-severe asthmatic patients. METHODS: In 28 adult patients with moderate-to-severe uncontrolled asthma, the comprehensive efficacy of 48-week dupilumab treatment, including the Cough and Sputum Assessment Questionnaire (CASA-Q), radiological mucus scores and airway dimensions on computed tomography (CT), was assessed prospectively. Treatment responsiveness to dupilumab was analyzed. RESULTS: With 48-week dupilumab treatment, all four cough and sputum domain scores of CASA-Q improved significantly. Radiological mucus scores and airway wall thickening on CT were significantly decreased. The decreases in mucus scores were significantly associated with improvements in Asthma Control Questionnaire scores, Asthma Quality of Life Questionnaire (AQLQ) overall scores, airway obstruction, and airway type 2 inflammation. When defined by > 0.5 improvement in AQLQ overall scores, 18 patients (64%) were identified as responders. CONCLUSIONS: Dupilumab reversed subjective and objective measures of airway mucus hypersecretion and some aspects of airway remodeling in patients with moderate-to-severe uncontrolled asthma.

Plasma D-Dimer Levels Can Provide Useful Diagnostic Information on Acute Vertebral Compression Fractures in Patients with Low Back Pain in the Emergency Room.

BACKGROUND: Patients with acute vertebral compression fractures (aVCFs) are frequently transferred to an emergency department by ambulance. The most useful imaging modality is magnetic resonance imaging (MRI); however, which patients should be prioritized for MRI evaluation may be unclear. The aim of this study was to evaluate plasma D-dimer levels as a biomarker for aVCFs. METHODS: This retrospective cohort study included patients with low back pain in the emergency department between November 2017 and October 2020. Patients with infections, patients with coagulation disorders, and patients without D-dimer level measurements were excluded. The presence of an aVCF was detected with MRI. Blood samples were collected for routine blood tests. The predictive factors for aVCFs were evaluated with univariate and multivariable logistic regression analyses. RESULTS: Overall, 191 consecutive MRI evaluations were ordered. After exclusions, 101 patients were reviewed. Based on MRI, 65 (64.4%) patients were diagnosed with aVCF. The presence of aVCF was significantly correlated with age (odds ratio [OR] = 1.052, 95% confidence interval [CI] 1.018-1.191), an old vertebral compression fracture (OR = 3.290, 95% CI 1.342-8.075), hemoglobin (OR = 0.699, 95% CI 0.535-0.912), and D-dimer levels (OR = 1.829, 95% CI 1.260-2.656). Results from a multivariable logistic regression analysis showed that D-dimer levels (OR = 1.642, 95% CI 1.188-2.228) remained a significant risk factor for the presence of aVCFs after adjustment for potential confounders. CONCLUSIONS: Plasma D-dimer levels can provide useful diagnostic information about whether an aVCF is present.

Skin care by washing with water is not inferior to washing with a cleanser in children with atopic dermatitis in remission in summer: WASH study.

BACKGROUND: Washing with water is not inferior to washing with soaps and detergents in children with atopic dermatitis (AD) in remission during the fall-winter seasons. We investigated whether this finding varies during summer based on the type of cleanser (soaps and detergents). METHODS: This evaluator-blinded, pragmatic, randomized, and non-inferiority study enrolled patients with AD whose eczema was controlled following regular steroid ointment application 2 days/week. For 8 ± 4 weeks, participants washed their upper and lower limbs with a cleanser on one side and with water alone on the other. Each participant chose either a weakly alkaline soap or an acidic detergent. The primary outcome was the Eczema Area and Severity Index (EASI) score at week 8 ± 4. RESULTS: The data of 43 of the 47 registered participants were analyzed. The median patient age was 44 (23-99) months; 28 and 15 participants chose weakly alkaline and acidic cleansers, respectively. At week 8 ± 4, EASI scores of the water and cleanser sides were 0.00 (0.00-0.40) and 0.15 (0.00-0.40), respectively (p = 0.74). The difference between both sides was 0.00 (-0.07 to 0.14); the limits of the 95 % confidence interval did not reach the pre-specified non-inferiority margin. No difference was observed in the median Patient-Oriented Eczema Measure score, number of additional steroid ointment applications, and occurrences of skin infections. There were no differences between the cleanser types in any of the results. CONCLUSIONS: We demonstrated that washing with water was not inferior to that with a cleanser in patients with AD in the maintenance phase during summer, regardless of the type of cleanser.

A Case of Symptomatic Multiple Tarlov Cysts Treated with Microsurgical Wrapping Technique -Efficacy and Limitation of Surgical Procedure.

Tarlov cysts (TCs) rarely cause clinical symptoms, such as leg pain, buttock pain, and bladder/bowel dysfunction. Surgery is considered when these symptoms persist despite medical treatments. Among several surgical procedures, microsurgical wrapping (MSW) is a relatively novel, simple technique with few complications, including cerebrospinal fluid leakage. Herein, we report a case of multiple TCs treated with MSW and present the mechanism of symptoms generated by TC and the procedure's limitations. A 58-year-old man complained of severe right leg and buttock pain for 3 months and was admitted to our hospital. His symptoms aggravated with sitting and standing and improved with the prone position. Spinal magnetic resonance imaging (MRI) demonstrated multiple sacral cysts containing intense cerebrospinal fluid. The cysts connect to the right S3 and S4 nerve roots. He was treated conservatively with medications; however, his symptoms were not improved. Therefore, MSW was performed for TCs connected to the S3 and S4 roots. The postoperative course was uneventful, and cerebrospinal fluid leakage did not occur. MRI performed 1 year after the operation demonstrated no recurrence of the TCs, and his leg pain was completely relieved; however, the buttock pain remained. MSW for TCs is effective for symptoms of adjacent nerve root compression; however, repairing the damaged nerve root in TCs is sometimes difficult. This may be a limitation of present surgical interventions because these symptoms may be difficult to treat even with other interventions.

Factors influencing slippage after microsurgical single level lumbar spinal decompression surgery - Are the psoas and multifidus muscles involved?

PURPOSE: Patients with lumbar spinal stenosis (LSS) require microsurgical decompression (MSD) surgery; however, MSD is often associated with postoperative instability at the operated level. Paraspinal muscles support the spinal column; lately, paraspinal volume has been used as a good indicator of sarcopenia. This study aimed to determine preoperative radiological factors, including paraspinal muscle volume, associated with postoperative slippage progression after MSD in LSS patients. METHODS: Patients undergoing single-level (L3/4 or L4/5) MSD for symptomatic LSS and followed-up for ≥ 5 years in our institute were reviewed retrospectively to measure preoperative imaging parameters focused on the operated level. Paraspinal muscle volumes (psoas muscle index [PMI] and multifidus muscle index [MFMI]) defined using the total cross-sectional area of each muscle/L3 vertebral body area in the preoperative lumbar axial CT) were calculated. Postoperative slippage in the form of static translation (ST) ≥ 2 mm was assessed on the last follow-up X-ray. RESULTS: We included 95 patients with average age and follow-up periods of 69 ± 8.2 years and 7.51 ± 2.58 years, respectively. PMI and MFMI were significantly correlated with age and significantly larger in male patients. Female sex, preoperative ST, dynamic translation, sagittal rotation angle, facet angle, pelvic incidence, lumbar lordosis, and PMI were correlated with long-term postoperative worsening of ST. However, as per multivariate analysis, no independent factor was associated with postoperative slippage progression. CONCLUSION: Lower preoperative psoas muscle volume in LSS patients is an important predictive factor of postoperative slippage progression at the operated level after MSD. The predictors for postoperative slippage progression are multifactorial; however, a well-structured postoperative exercise regimen involving psoas muscle strengthening may be beneficial in LSS patients after MSD.

Changes in spinal sagittal balance after a new osteoporotic vertebral compression fracture.

We conduct a longitudinal study to examine how new VCF alter spinal sagittal balance. New VCF increased SVA by an average of 2.8 cm. Sagittal balance deteriorates as a VCF develops in the lower lumbar spine. A new fracture below L1 increased the relative risk of a deterioration of sagittal balance 2.9-fold compared to one above Th12. PURPOSE: Studies on the relationship between osteoporotic vertebral fractures and spinal sagittal balance have all been limited to cross-sectional studies. The aim of this study is to conduct a longitudinal study to examine how new vertebral compression fracture (VCF) alter spinal sagittal balance. METHODS: Subjects were patients undergoing periodic examinations after treatment of a vertebral fracture or lumbar spinal canal stenosis. Forty patients who developed a new VCF were included in this study. Full-spine standing radiographs were compared before and after the fracture to examine changes in spinopelvic parameters and factors determining the changes in sagittal balance. RESULTS: The mean age of the patients was 79.0 years. The mean interval between pre- and post-fracture radiographs was 22.7 months, and the mean time between development of a fracture and post-fracture radiographs was 4.6 months. After a fracture, sagittal vertical axis (SVA) increased an average of 2.78 cm and spino-sacral angle (SSA) decreased an average of 5.3°. Both ⊿SVA and ⊿SSA were not related to pre-fracture parameters. The wedge angle of the fractured vertebra was not related to changes in sagittal balance. ⊿SVA increased markedly in patients with a fracture of the lower lumbar vertebrae. receiver operating characteristic analysis revealed that the relative risk of a deterioration of sagittal balance was 2.9 times higher for a new fracture below L1 than for a fracture above Th12. CONCLUSION: New VCF increased SVA by an average of 2.8 cm. Sagittal balance deteriorates as a new fracture develops in the lower lumbar spine. Early intervention in osteoporosis is vital for the elderly.

Structural insights into the complex of oncogenic KRas4BG12V and Rgl2, a RalA/B activator.

About a quarter of total human cancers carry mutations in Ras isoforms. Accumulating evidence suggests that small GTPases, RalA, and RalB, and their activators, Ral guanine nucleotide exchange factors (RalGEFs), play an essential role in oncogenic Ras-induced signalling. We studied the interaction between human KRas4B and the Ras association (RA) domain of Rgl2 (Rgl2RA), one of the RA-containing RalGEFs. We show that the G12V oncogenic KRas4B mutation changes the interaction kinetics with Rgl2RA The crystal structure of the KRas4BG12V: Rgl2RA complex shows a 2:2 heterotetramer where the switch I and switch II regions of each KRasG12V interact with both Rgl2RA molecules. This structural arrangement is highly similar to the HRasE31K:RALGDSRA crystal structure and is distinct from the well-characterised Ras:Raf complex. Interestingly, the G12V mutation was found at the dimer interface of KRas4BG12V with its partner. Our study reveals a potentially distinct mode of Ras:effector complex formation by RalGEFs and offers a possible mechanistic explanation for how the oncogenic KRas4BG12V hyperactivates the RalA/B pathway.

Low Daily Step Count Associated with Small Erector Spine Muscle Area and Sarcopenia in Idiopathic Pulmonary Fibrosis.

Objective The daily step count is associated with mortality in idiopathic pulmonary fibrosis (IPF). However, the factors associated with this phenomenon are not yet fully understood. We therefore clarified its association with clinical parameters. Methods Fifty-nine patients with IPF with available data for daily step counts; 6-minute walk distance (6MWD); chest, abdominal, and pelvic computed tomography (CT); pulmonary function; psychological evaluations; and sarcopenia assessments were prospectively enrolled. The daily step count was measured continuously for seven consecutive days. The cross-sectional areas of the erector spinae muscles at the level of the 12th vertebra (ESMCSA) and psoas major muscle volume (PMV) obtained by CT were assessed. Results The average age of the patients was 73.3±8.1 years old, and the percent predicted forced vital capacity was 81.6% ±15.8%. The average daily step count was 4,258 (2,155-6,991) steps. The average 6MWD, ESMCSA, and PMV were 413±97 m, 25.5±6.7 cm2, and 270±75.6 cm3, respectively. A linear regression analysis for daily step count showed that the ESMCSA and 6MWD were independent factors for the daily step count, whereas the PMV and skeletal muscle index were not. The daily step count, ESMCSA, and 6MWD were lower in patients with sarcopenia than in those without sarcopenia. Conclusions A lower daily step count was associated with a smaller erector spinae muscle area and sarcopenia in patients with IPF. Further studies are warranted to confirm the importance of physical therapy for muscle strengthening in patients with IPF.

Ablation of Dual-Specificity Phosphatase 6 Protects against Nonalcoholic Fatty Liver Disease via Cytochrome P450 4A and Mitogen-Activated Protein Kinase.

Dual-specificity phosphatase 6 (DUSP6) is a specific phosphatase for mitogen-activated protein kinase (MAPK). This study used a high-fat diet (HFD)-induced murine nonalcoholic fatty liver disease model to investigate the role of DUSP6 in this disease. Wild-type (WT) and Dusp6-haploinsufficiency mice developed severe obesity and liver pathology consistent with nonalcoholic fatty liver disease when exposed to HFD. In contrast, Dusp6-knockout (KO) mice completely eliminated these phenotypes. Furthermore, primary hepatocytes isolated from WT mice exposed to palmitic and oleic acids exhibited abundant intracellular lipid accumulation, whereas hepatocytes from Dusp6-KO mice showed minimal lipid accumulation. Transcriptome analysis revealed significant down-regulation of genes encoding cytochrome P450 4A (CYP4A), known to promote ω-hydroxylation of fatty acids and hepatic steatosis, in Dusp6-KO hepatocytes compared with that in WT hepatocytes. Diminished CYP4A expression was observed in the liver of Dusp6-KO mice compared with WT and Dusp6-haploinsufficiency mice. Knockdown of DUSP6 in HepG2, a human liver-lineage cell line, also promoted a reduction of lipid accumulation, down-regulation of CYP4A, and up-regulation of phosphorylated/activated MAPK. Furthermore, inhibition of MAPK activity promoted lipid accumulation in DUSP6-knockdown HepG2 cells without affecting CYP4A expression, indicating that CYP4A expression is independent of MAPK activation. These findings highlight the significant role of DUSP6 in HFD-induced steatohepatitis through two distinct pathways involving CYP4A and MAPK.

Interactions of the N- and C-Terminal SH3 Domains of Drosophila Drk with the Proline-Rich Peptides from Sos and Dos.

Drk, a homologue of human GRB2 in Drosophila, receives signals from outside the cells through the interaction of its SH2 domain with the phospho-tyrosine residues in the intracellular regions of receptor tyrosine kinases (RTKs) such as Sevenless, and transduces the signals downstream through the association of its N- and C-terminal SH3 domains (Drk-NSH3 and Drk-CSH3, respectively) with proline-rich motifs (PRMs) in Son of Sevenless (Sos) or Daughter of Sevenless (Dos). Isolated Drk-NSH3 exhibits a conformational equilibrium between the folded and unfolded states, while Drk-CSH3 adopts only a folded confirmation. Drk interacts with PRMs of the PxxPxR motif in Sos and the PxxxRxxKP motif in Dos. Our previous study has shown that Drk-CSH3 can bind to Sos, but the interaction between Drk-NSH3 and Dos has not been investigated. To assess the affinities of both SH3 domains towards Sos and Dos, we conducted NMR titration experiments using peptides derived from Sos and Dos. Sos-S1 binds to Drk-NSH3 with the highest affinity, strongly suggesting that the Drk-Sos multivalent interaction is initiated by the binding of Sos-S1 and NSH3. Our results also revealed that the two Sos-derived PRMs clearly favour NSH3 for binding, whereas the two Dos-derived PRMs show almost similar affinity for NSH3 and CSH3. We have also performed docking simulations based on the chemical shift perturbations caused by the addition of Sos- and Dos-derived peptides. Finally, we discussed the various modes in the interactions of Drk with Sos/Dos.