F-actin regulates the polarized secretion of pollen tube attractants in Arabidopsis synergid cells.

Pollen tube attraction is a key event of sexual reproduction in flowering plants. In the ovule, two synergid cells neighboring the egg cell control pollen tube arrival via the active secretion of attractant peptides such as AtLURE1 and XIUQIU from the filiform apparatus (FA) facing toward the micropyle. Distinctive cell polarity together with longitudinal F-actin and microtubules are hallmarks of the synergid cell in various species, though the functions of these cellular structures are unclear. In this study, we used genetic and pharmacological approaches to indicate the roles of cytoskeletal components in FA formation and pollen tube guidance in Arabidopsis thaliana. Genetic inhibition of microtubule formation reduced invaginations of the plasma membrane but did not abolish micropylar AtLURE1.2 accumulation. By contrast, the expression of a dominant-negative form of ACTIN8 induced disorganization of the FA and loss of polar AtLURE1.2 distribution toward the FA. Interestingly, after pollen tube reception, F-actin became unclear for a few hours in the persistent synergid cell, which may be involved in pausing and resuming pollen tube attraction during early polytubey block. Our data suggest that F-actin plays a central role in maintaining cell polarity and in mediating male-female communication in the synergid cell.

Role for Caspase-8 in the Release of IL-1ß and Active Caspase-1 from Viable Human Monocytes during Toxoplasma gondii Infection.

Monocytes are actively recruited to sites of infection and produce the potent proinflammatory cytokine IL-1ß. We previously showed that IL-1ß release during Toxoplasma gondii infection of primary human monocytes requires the NLRP3 inflammasome and caspase-1 but is independent of gasdermin D and pyroptosis. To investigate mechanisms of IL-1ß release, we generated caspase-1, -4, -5, or -8 knockout (KO) THP-1 monocytic cells. Genetic ablation of caspase-1 or -8, but not caspase-4 or -5, decreased IL-1ß release during T. gondii infection without affecting cell death. In contrast, TNF-α and IL-6 secretion were unperturbed in caspase-8 KO cells during T. gondii infection. Dual pharmacological inhibition of caspase-8 and RIPK1 in primary monocytes also decreased IL-1ß release without affecting cell viability or parasite infection. Caspase-8 was also required for the release of active caspase-1 from T. gondii-infected cells and for IL-1ß release during infection with the related apicomplexan parasite Neospora caninum. Surprisingly, caspase-8 deficiency did not impair synthesis or cleavage of pro-IL-1ß, but resulted in the retention of mature IL-1ß within cells. Generation of gasdermin E KO and ATG7 KO THP-1 cells revealed that the release of IL-1ß was not dependent on gasdermin E or ATG7. Collectively, our data indicate that during T. gondii Infection of human monocytes, caspase-8 functions in a novel gasdermin-independent mechanism controlling IL-1ß release from viable cells. This study expands on the molecular pathways that promote IL-1ß in human immune cells and provides evidence of a role for caspase-8 in the mechanism of IL-1ß release during infection.

Abolishing the prelamin A ZMPSTE24 cleavage site leads to progeroid phenotypes with near-normal longevity in mice.

Prelamin A is a farnesylated precursor of lamin A, a nuclear lamina protein. Accumulation of the farnesylated prelamin A variant progerin, with an internal deletion including its processing site, causes Hutchinson-Gilford progeria syndrome. Loss-of-function mutations in ZMPSTE24, which encodes the prelamin A processing enzyme, lead to accumulation of full-length farnesylated prelamin A and cause related progeroid disorders. Some data suggest that prelamin A also accumulates with physiological aging. Zmpste24-/- mice die young, at ∼20 wk. Because ZMPSTE24 has functions in addition to prelamin A processing, we generated a mouse model to examine effects solely due to the presence of permanently farnesylated prelamin A. These mice have an L648R amino acid substitution in prelamin A that blocks ZMPSTE24-catalyzed processing to lamin A. The LmnaL648R/L648R mice express only prelamin and no mature protein. Notably, nearly all survive to 65 to 70 wk, with ∼40% of male and 75% of female LmnaL648R/L648R mice having near-normal lifespans of 90 wk (almost 2 y). Starting at ∼10 wk of age, LmnaL648R/L648R mice of both sexes have lower body masses than controls. By ∼20 to 30 wk of age, they exhibit detectable cranial, mandibular, and dental defects similar to those observed in Zmpste24-/- mice and have decreased vertebral bone density compared to age- and sex-matched controls. Cultured embryonic fibroblasts from LmnaL648R/L648R mice have aberrant nuclear morphology that is reversible by treatment with a protein farnesyltransferase inhibitor. These novel mice provide a model to study the effects of farnesylated prelamin A during physiological aging.

Zingiber officinale promotes autophagy and apoptosis in human oral cancer through the C/EBP homologous protein.

The rhizome of Zingiber officinale (Z. officinale), commonly known as ginger, has been characterized as a potential drug candidate due to its antitumor effects. However, the chemotherapeutic effect of ginger on human oral cancer remains poorly understood. In this study, we examined the effects of an ethanol extract of Z. officinale rhizomes (ZOE) on oral cancer and identified the components responsible for its pharmacological activity. ZOE exerts its inhibitory activity in oral cancer by inducing both autophagy and apoptosis simultaneously. Mechanistically, ZOE-induced autophagy and apoptosis in oral cancer are attributed to the reactive oxygen species (ROS)-mediated endoplasmic reticulum stress response. Additionally, we identified two active components of ZOE, 1-dehydro-6-gingerdione and 8-shogaol, which were sufficient to stimulate autophagy initiation and apoptosis induction by enhancing CHOP expression. These results suggest that ZOE and its two active components induce ROS generation, upregulate CHOP, initiate autophagy and apoptosis, and hold promising therapeutics against human oral cancer.

Valproate use associated with frontal and cerebellar gray matter volume reductions: A voxel-based morphometry study.

Recent morphometric magnetic resonance imaging (MRI) studies suggested the possibility that valproate (VPA) use is associated with parieto-occipital cortical thinning in patients with heterogeneous epilepsy syndromes. In this study, we examined the effect of VPA on the brain volume using a large number of homogenous patients with idiopathic generalized epilepsy. Voxel-based morphometry was used to compare regional gray matter (GM) volume between 112 patients currently taking VPA (VPA+ group), 81 patients not currently taking VPA (VPA- group), and 120 healthy subjects (control group). The VPA+ group showed a significant GM volume reduction in the bilateral cerebellum, hippocampus, insula, caudate nucleus, medial frontal cortex/anterior cingulate cortex, primary motor/premotor cortex, medial occipital cortex, and anteromedial thalamus, as compared to the control group. The VPA- group showed a significant GM volume reduction in the anteromedial thalamus and right hippocampus/temporal cortex, as compared to the control group. Compared to the VPA- group, the VPA+ group had a significant GM volume reduction in the bilateral cerebellum, primary motor/premotor cortex, and medial frontal cortex/anterior cingulate cortex. We have provided evidence that VPA use could result in GM volume reductions in the frontal cortex and cerebellum. Our findings should be acknowledged as a potential confounding factor in morphometric MRI studies that include subjects taking VPA.

Six-year trend of subsequent allergic diseases following Kawasaki disease and its clinical implications: A population-based matched cohort study of 34,712 patients.

BACKGROUND: It has been suggested that allergic diseases may increase after Kawasaki disease (KD). We aimed to analyze the temporal patterns of allergic disease incidence after KD. METHODS: A nationwide population-based matched cohort study was conducted using data from the Korean National Health Insurance claims database. Patients aged <5 years diagnosed with KD and their 1:3 propensity score-matched controls were included. Three cohorts were established: Cohort A, patients with allergies; Cohort B, patients without allergies; and Cohort C, patients without allergies, but excluding patients with birth history and underlying medical conditions. Cumulative incidence rates (%) and associated hospital visits for allergic rhinitis, atopic dermatitis, urticaria, and asthma were compared between the cases and controls during the 6-year follow-up period. RESULTS: The study population comprised 8678 patients diagnosed with KD and 26,034 controls. In Cohort A, although initially, there were intergroup differences in the number of hospital visits for certain allergic diseases, these differences were inconsistent and varied depending on the type of allergic disease. Over time, the differences narrowed, and by the sixth year, the gap had decreased significantly. In Cohorts B and C, the initial incidence rates of the four allergic diseases and associated hospital visits were lower in patients with KD as compared to controls. However, with a faster rate of increase, the incidence rates and number of hospital visits eventually surpassed those of the controls. CONCLUSIONS: The pattern of delayed increase in cumulative incidence rates and hospital visits for allergic diseases after KD suggests the possibility of a shared genetic or immunologic susceptibility between KD and allergic diseases, which becomes evident over time, rather than a direct influence of KD resulting in allergic diseases.

Chemoembolization versus radiofrequency ablation for single small (≤ 3 cm) hepatocellular carcinoma: a propensity score matching analysis.

OBJECTIVES: To compare the efficacy of transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) for patients with single small (≤ 3 cm) hepatocellular carcinoma (HCC) and preserved liver function (Child-Pugh class A). MATERIALS AND METHODS: The clinical features of treatment-naïve patients who underwent TACE and RFA as first-line treatment were balanced through propensity score matching (PSM). The primary endpoint was overall survival (OS), and the secondary endpoints were local tumor recurrence (LTR) and recurrence-free survival (RFS). RESULTS: The analysis included 440 patients who received TACE, and 430 patients who received RFA. After PSM adjustment (323 pairs), the 5- and 10-year OS rates were 81% and 61%, respectively, in patients who underwent RFA, and 77% and 51%, respectively, for patients who underwent TACE (p = 0.021). Subgroup analyses showed that OS, LTR, and RFS were homogeneously better in the RFA group. CONCLUSION: RFA was associated with better survival outcomes than TACE in patients with single small HCC and preserved liver function. CLINICAL RELEVANCE STATEMENT: This large-scale comparative study provides evidence that radiofrequency ablation has a better overall survival rate than chemoembolization for small (≤ 3 cm) hepatocellular carcinomas. KEY POINTS: • The relative effectiveness of transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) for early HCC is unclear. • Overall survival rate was significantly higher in the RFA group. • The effects of RFA on overall survival, local tumor recurrence, and recurrence-free survival were homogeneously better in all subgroups.

Stent-Graft Placement for Hepatic Arterial Hemorrhage after Pancreaticobiliary Surgery: Long-Term Clinical Outcomes.

PURPOSE: To evaluate the safety and long-term clinical outcomes of stent-graft placement to treat hepatic arterial hemorrhage after pancreaticobiliary surgery. MATERIALS AND METHODS: Outcomes were retrospectively evaluated in 61 patients (50 men and 11 women; mean age, 63 years) who underwent stent-graft placement for delayed arterial hemorrhage (after 24 hours) after pancreaticobiliary surgery from 2006 to 2023. Bleeding sites included the gastroduodenal artery stump (n = 54), common or proper hepatic artery (n = 5), and right hepatic artery (n = 2). The stent-grafts used were Viabahn (n = 27), Comvi (n = 11), Jostent (n = 3), Covera (n = 11), and Lifestream (n = 7). Technical and clinical success and adverse events (AE) were evaluated. After stent-graft placement, overall survival (OS), hemorrhage-free survival (HFS), and stent patency were evaluated. RESULTS: The technical and clinical success rates of stent-graft placement were 97% and 93%, respectively. The severe AE rate was 12% and was significantly higher in patients who underwent pylorus-sacrificing rather than pylorus-preserving surgery (P = .001). None of the severe AEs were associated with patient mortality. Median OS after stent-graft placement was 854 days, and median HFS was 822 days. The 1-, 3-, 5-, and 10-year stent patency rates were 87%, 84%, 79%, and 72%, respectively. CONCLUSIONS: Stent-graft placement was safe and provided long-term control of hepatic arterial hemorrhage after pancreaticobiliary surgery.

Facile and cost-effective fabrication of wearable alpha-naphtholphthalein-based halochromic sensor for wound pH monitoring.

The sensor, designed to be worn directly on the skin, is suitable for real-time monitoring of the recovery level of not only general wounds, but also difficult-to-heal wounds, such as those with chronic inflammation. Notably, healthy skin has a pH range of 4-6. When a wound occurs, the pH is known to be approximately 7.4. In this study, alpha-naphtholphthalein (Naph) was immersed in a cotton-blended textile to produce a wearable halochromic sensor that clearly changed color depending on the pH of the skin in the range 6-9, including pH 7.4, which is the skin infection state. The coating was performed without using an organic solvent by dissolving it in micelle form using cetyltrimethylammonium bromide, a surfactant, in water. Naph-based halochromic sensor shows light yellow, which is the dye's own color, at pH 6, which is a healthy skin condition, and gradually showed a clear color change to light green-green-blue as pH increased. Even after washing and drying by rubbing with regular tap water, the color change due to pH was maintained more than 10 times. Naph-based halochromic sensors use a simple solution production and coating method and are not only reusable sensors that can be washed with water but also use environmentally friendly water, making them very suitable for developing commercial products for wound pH monitoring. In addition, it can be easily applied to medical supplies, such as medical gauze, patient clothes, and compression bandages, as well as everyday wear, such as clothing, gloves, and socks. Therefore, it is expected to be widely used as a wound pH sensor, allowing real-time monitoring of the skin condition of individuals with chronic skin inflammation, including patients requiring wound recovery.

Exposure to ambient air pollution mixture and senescence-associated secretory phenotype proteins among middle-aged and older women.

Our study aimed to investigate the impact of environmental exposures, such as ambient air pollutants, on systemic inflammation and cellular senescence in middle-aged and older women. We utilized epidemiological data linked with exposure data of six air pollutants (particulate matters [PM10, PM2.5], sulphur dioxide [SO2], nitrogen dioxide [NO2], carbon monoxide [CO], and ozone [O3]) and blood samples of 380 peri- and postmenopausal women participants of the Korean Genome and Epidemiology Study. We measured blood high-sensitivity C-reactive protein (hsCRP) and age-related 27 circulatory senescence-associated secretory phenotypes (SASP) produced by senescent cells. We employed single exposure models to explore the general pattern of association between air pollution exposure and proteomic markers. Using quantile g-computation models, we assessed the association of six air pollutant mixtures with hsCRP and SASP proteins. In single-exposure, single-period models, nine out of the 27 SASP proteins including IFN-γ (ß = 0.04, 95% CI: 0.01, 0.07 per interquartile range-increase), IL-8 (0.15, 95% CI: 0.09, 0.20), and MIP1α (0.11, 95% CI: 0.04, 0.18) were positively associated with the average level of O3 over one week. Among the age-related SASP proteins, IFN-γ (0.11, 95% CI: 0.03, 0.20) and IL-8 (0.22, 95% CI: 0.05, 0.39) were positively associated with exposure to air pollutant mixture over one week. The MIP1ß was higher with an increasing one-month average concentration of the air pollutant mixture (0.11, 95% CI: 0.00, 0.21). The IL-8 showed consistently positive association with the ambient air pollutant mixture for the exposure periods ranging from one week to one year. O3 predominantly showed positive weights in the associations between air pollutant mixtures and IL-8. These findings underscore the potential of proteomic indicators as markers for biological aging attributed to short-term air pollution exposure.

Successful pregnancy outcome via in-vitro fertilization and laparoscopic resection of non-communicating rudimentary horn pregnancy containing early pregnancy: a case report.

BACKGROUND: Non-communicating rudimentary horn pregnancy (NCRHP) lead to life-threatening condition for both mother and fetus. Early diagnosis of NCRHP and laparoscopic resection is important to prevent catastrophic conditions. However, delayed diagnosis until the second or third trimester makes it difficult to accurately diagnose between NCRHP and bicornuate uterine pregnancy, as both conditions present uterine rupture and massive hemoperitoneum. Furthermore, these rare cases are challenging in pregnancy trials and associated with adverse outcomes in subsequent pregnancies. CASE PRESENTATION: A 31-year-old gravida 1 para 0 Korean woman visited our infertility center with a confirmed positive urine pregnancy test after timed intercourse. Before she was scheduled to have timed intercourse, a unicornuate uterus with a non-communicating right uterine horn was suspected based on an ultrasound scan and hysterosalpingography during the initial infertility workup. A gestational sac was observed in the right non-communicating rudimentary horn at 5 weeks of gestation. Serum beta-human chorionic gonadotropin (b-hCG) level was 2052.0mIU/mL. An elective laparoscopic resection of the right rudimentary horn containing a gestational sac, along with ipsilateral salpingectomy, was performed with no adverse event. After 3-month of recovery period and three cycles of conceptional trials involving timed intercourse and intrauterine insemination, in-vitro fertilization (IVF) was performed using the antagonist protocol, and successful pregnancy was confirmed. The patient had been hospitalized from 21 + 6 weeks to 35 + 6 weeks of gestation, underwent cerclage placement and tocolytics with corticosteroid treatment. She delivered an early-term male baby by cesarean section. CONCLUSION: In this rare case, the successful pregnancy achieved through IVF following the appropriate management of NCRHP under laparoscopy underscores the critical importance of early diagnosis and intervention in cases of NCRHP. Timely identification and management of NCRHP are vital to prevent the occurrence of catastrophic conditions and to enhance the prognosis of a successful pregnancy through assisted reproductive technology (ART). Therefore, a high index of suspicion for NCRHP is important and employs a range of diagnostic modalities.

Maximal detrusor pressure can be predicted using technetium-99m-mertcaptoacetyltriglycine renal scintigraphy in the early stages of spinal cord injury.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To investigate the potential of technetium-99m-mercaptoacetyltriglycine (99mTc-MAG-3) renal scintigraphy for predicting maximal detrusor pressure in the early stages of spinal cord injury (SCI). SETTING: Tertiary rehabilitation facility. METHODS: Medical records of individuals with SCI admitted between January 2020 and April 2023 who underwent both 99mTc-MAG-3 renal scintigraphy and urodynamic study within 90 days of SCI onset were retrospectively reviewed. Pearson's coefficient analysis was performed to determine the relationship between 99mTc-MAG-3 renal scintigraphy findings and urodynamic study findings. A multivariate linear regression analysis was performed to determine the best predictors of maximal detrusor pressure. A multivariate logistic regression analysis was performed to determine risk factors for high detrusor pressure. RESULTS: Ninety-four participants were enrolled in this study. Pearson's correlation analysis showed that effective renal plasma flow (ERPF) and ERPF (% predicted) were significantly correlated with maximal detrusor pressure. The multivariate linear regression analysis demonstrated that ERPF (% predicted) was a significant predictor of maximal detrusor pressure. The multivariate logistic regression analysis showed that ERPF (% predicted) was significantly associated with high detrusor pressure. The receiver operating characteristic curve demonstrated that the predictive model had an area under the curve of 0.725, with an ERPF (% predicted) cut-off of 64.05%, sensitivity 1.000, and specificity 0.429. CONCLUSIONS: These results suggest that 99mTc-MAG-3 renal scintigraphy may be useful for predicting high detrusor pressure in early SCI and may guide the timing of urodynamic studies in individuals with early SCI for appropriate management of neurogenic lower urinary tract dysfunction.

Pulmonary function and sarcopenia as predictors of dysphagia in cervical spinal cord injury.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine the risk factors associated with dysphagia in individuals with cervical spinal cord injury (CSCI) and analyze the differences between individuals with improved penetration-aspiration (PA) and persistent PA on follow-up. SETTING: Tertiary inpatient rehabilitation facilities. METHODS: Medical records of individuals with CSCI admitted between December 2009 and February 2023 who underwent a videofluoroscopic swallowing study (VFSS) were retrospectively reviewed. Multivariate logistic regression analysis was performed to assess risk factors for dysphagia. Differences between individuals with improved PA and persistent PA were analyzed using an independent t-test. RESULTS: In total, 149 participants were enrolled. Age (odds ratio (OR) 1.08, 95% confidence interval (CI) 1.04-1.12), percentage of forced vital capacity to predicted normal (FVC (% predicted)) (OR 0.90, 95% CI 0.85-0.94), and skeletal muscle index (OR 0.89, 95% CI, 0.79-0.99) were significant factors associated with the risk of PA. Based on the receiver operating characteristic curve analysis, the cut-off values for age, FVC (% predicted), and skeletal muscle index were determined as 56.0, 45.7, and 41.0, respectively. A secondary analysis of the follow-up VFSS was conducted on 38 participants. The follow-up FVC (% predicted) and degree of weight loss differed significantly between the improved PA and persistent PA groups. CONCLUSIONS: Older age, low FVC (% predicted), and low skeletal muscle index can be predictors of dysphagia in patients with CSCI. On follow-up VFSS, individuals with improved PA demonstrated greater improvement in FVC (% predicted).

Prevalence and Associated Factors of Depression and Anxiety Among Healthcare Workers During the Coronavirus Disease 2019 Pandemic: A Nationwide Study in Korea.

BACKGROUND: A healthcare system's collapse due to a pandemic, such as the coronavirus disease 2019 (COVID-19), can expose healthcare workers (HCWs) to various mental health problems. This study aimed to investigate the impact of the COVID-19 pandemic on the depression and anxiety of HCWs. METHODS: A nationwide questionnaire-based survey was conducted on HCWs who worked in healthcare facilities and public health centers in Korea in December 2020. Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) were used to measure depression and anxiety. To investigate factors associated with depression and anxiety, stepwise multiple logistic regression analysis was performed. RESULTS: A total of 1,425 participating HCWs were included. The mean depression score (PHQ-9) of HCWs before and after COVID-19 increased from 2.37 to 5.39, and the mean anxiety score (GAD-7) increased from 1.41 to 3.41. The proportion of HCWs with moderate to severe depression (PHQ-9 ≥ 10) increased from 3.8% before COVID-19 to 19.5% after COVID-19, whereas that of HCWs with moderate to severe anxiety (GAD-7 ≥ 10) increased from 2.0% to 10.1%. In our study, insomnia, chronic fatigue symptoms and physical symptoms after COVID-19, anxiety score (GAD-7) after COVID-19, living alone, and exhaustion were positively correlated with depression. Furthermore, post-traumatic stress symptoms, stress score (Global Assessment of Recent Stress), depression score (PHQ-9) after COVID-19, and exhaustion were positively correlated with anxiety. CONCLUSION: In Korea, during the COVID-19 pandemic, HCWs commonly suffered from mental health problems, including depression and anxiety. Regularly checking the physical and mental health problems of HCWs during the COVID-19 pandemic is crucial, and social support and strategy are needed to reduce the heavy workload and psychological distress of HCWs.

Engineering the Strain and Interlayer Excitons of 2D Materials via Lithographically Engraved Hexagonal Boron Nitride.

Strain engineering has quickly emerged as a viable option to modify the electronic, optical, and magnetic properties of 2D materials. However, it remains challenging to arbitrarily control the strain. Here we show that, by creating atomically flat surface nanostructures in hexagonal boron nitride, we achieve an arbitrary on-chip control of both the strain distribution and magnitude on high-quality molybdenum disulfide. The phonon and exciton emissions are shown to vary in accordance with our strain field designs, enabling us to write and draw any photoluminescence color image in a single chip. Moreover, our strain engineering offers a powerful means to significantly and controllably alter the strengths and energies of interlayer excitons at room temperature. This method can be easily extended to other material systems and offers promise for functional excitonic devices.

Exploring the Role of Gut Microbiota in Patients with Alopecia Areata.

Imbalances in gut microbiota reportedly contribute to the development of autoimmune diseases, but the association between the etiopathogenesis of alopecia areata (AA) and gut microbial dysbiosis remains unclear. This cross-sectional study was conducted to identify and compare the composition of the gut microbiome in patients affected by AA and those in a healthy control (HC) group, and to investigate possible bacterial biomarkers for the disease. Fecal samples were collected from 19 AA patients and 20 HCs to analyze the relationship with fecal bacteria. The three major genera constituting the gut microbiome of AA patients were Bacteroides, Blautia, and Faecalibacterium. The alpha diversity of the AA group was not statistically significant different from that of the HC group. However, bacterial community composition in the AA group was significantly different from that of HC group according to Jensen-Shannon dissimilarities. In patients with AA, we found an enriched presence of the genera Blautia and Eubacterium_g5 compared to the HC group (p < 0.05), whereas Bacteroides were less prevalent (p < 0.05). The gut microbiota of AA patients was distinct from those of the HC group. Our findings suggest a possible involvement of gut microbiota in in the as-yet-undefined pathogenesis of AA.

Recombinant expression and tryptophan-assisted analysis of human sweet taste receptor T1R3's extracellular domain in sweetener interaction studies.

The human palate can discern multiple tastes; however, it predominantly perceives five fundamental flavors: sweetness, saltiness, sourness, bitterness, and umami. Sweetness is primarily mediated through the sweet taste receptor, a membrane-bound heterodimeric structure comprising T1R2-T1R3. However, unraveling the structural and mechanistic intricacies of the sweet taste receptor has proven challenging. This study aimed to address this knowledge gap by expressing an extracellular N-terminal domain encompassing the cysteine-rich domain of human hT1R3 (hT1R3-TMD) in Escherichia coli. The expressed protein was obtained as inclusion bodies, purified by metal affinity chromatography, and refolded using the dilution-refolding method. Through rigorous analysis, we confirmed the successful refolding of hT1R3-TMD and elucidated its structural characteristics using circular dichroism spectroscopy. Notably, the refolded protein was found to exist as either a monomer or a dimer, depending on its concentration. A tryptophan fluorescence quenching assay revealed that the dissociation constants for sucrose, sucralose, and brazzein were >9500 µM, 2380 µM and 14.3 µM, respectively. Our findings highlight the utility of this E. coli expression system for producing functional hT1R3-TMD for investigations and demonstrate the efficacy of the tryptophan fluorescence quenching assay in revealing complex interactions between sweet taste receptors and various sweeteners.

Targeting FLT3-TAZ signaling to suppress drug resistance in blast phase chronic myeloid leukemia.

BACKGROUND: Although the development of BCR::ABL1 tyrosine kinase inhibitors (TKIs) rendered chronic myeloid leukemia (CML) a manageable condition, acquisition of drug resistance during blast phase (BP) progression remains a critical challenge. Here, we reposition FLT3, one of the most frequently mutated drivers of acute myeloid leukemia (AML), as a prognostic marker and therapeutic target of BP-CML. METHODS: We generated FLT3 expressing BCR::ABL1 TKI-resistant CML cells and enrolled phase-specific CML patient cohort to obtain unpaired and paired serial specimens and verify the role of FLT3 signaling in BP-CML patients. We performed multi-omics approaches in animal and patient studies to demonstrate the clinical feasibility of FLT3 as a viable target of BP-CML by establishing the (1) molecular mechanisms of FLT3-driven drug resistance, (2) diagnostic methods of FLT3 protein expression and localization, (3) association between FLT3 signaling and CML prognosis, and (4) therapeutic strategies to tackle FLT3+ CML patients. RESULTS: We reposition the significance of FLT3 in the acquisition of drug resistance in BP-CML, thereby, newly classify a FLT3+ BP-CML subgroup. Mechanistically, FLT3 expression in CML cells activated the FLT3-JAK-STAT3-TAZ-TEAD-CD36 signaling pathway, which conferred resistance to a wide range of BCR::ABL1 TKIs that was independent of recurrent BCR::ABL1 mutations. Notably, FLT3+ BP-CML patients had significantly less favorable prognosis than FLT3- patients. Remarkably, we demonstrate that repurposing FLT3 inhibitors combined with BCR::ABL1 targeted therapies or the single treatment with ponatinib alone can overcome drug resistance and promote BP-CML cell death in patient-derived FLT3+ BCR::ABL1 cells and mouse xenograft models. CONCLUSION: Here, we reposition FLT3 as a critical determinant of CML progression via FLT3-JAK-STAT3-TAZ-TEAD-CD36 signaling pathway that promotes TKI resistance and predicts worse prognosis in BP-CML patients. Our findings open novel therapeutic opportunities that exploit the undescribed link between distinct types of malignancies.

Reprogramming anchorage dependency by adherent-to-suspension transition promotes metastatic dissemination.

BACKGROUND: Although metastasis is the foremost cause of cancer-related death, a specialized mechanism that reprograms anchorage dependency of solid tumor cells into circulating tumor cells (CTCs) during metastatic dissemination remains a critical area of challenge. METHODS: We analyzed blood cell-specific transcripts and selected key Adherent-to-Suspension Transition (AST) factors that are competent to reprogram anchorage dependency of adherent cells into suspension cells in an inducible and reversible manner. The mechanisms of AST were evaluated by a series of in vitro and in vivo assays. Paired samples of primary tumors, CTCs, and metastatic tumors were collected from breast cancer and melanoma mouse xenograft models and patients with de novo metastasis. Analyses of single-cell RNA sequencing (scRNA-seq) and tissue staining were performed to validate the role of AST factors in CTCs. Loss-of-function experiments were performed by shRNA knockdown, gene editing, and pharmacological inhibition to block metastasis and prolong survival. RESULTS: We discovered a biological phenomenon referred to as AST that reprograms adherent cells into suspension cells via defined hematopoietic transcriptional regulators, which are hijacked by solid tumor cells to disseminate into CTCs. Induction of AST in adherent cells 1) suppress global integrin/ECM gene expression via Hippo-YAP/TEAD inhibition to evoke spontaneous cell-matrix dissociation and 2) upregulate globin genes that prevent oxidative stress to acquire anoikis resistance, in the absence of lineage differentiation. During dissemination, we uncover the critical roles of AST factors in CTCs derived from patients with de novo metastasis and mouse models. Pharmacological blockade of AST factors via thalidomide derivatives in breast cancer and melanoma cells abrogated CTC formation and suppressed lung metastases without affecting the primary tumor growth. CONCLUSION: We demonstrate that suspension cells can directly arise from adherent cells by the addition of defined hematopoietic factors that confer metastatic traits. Furthermore, our findings expand the prevailing cancer treatment paradigm toward direct intervention within the metastatic spread of cancer.

A lamin A/C variant causing striated muscle disease provides insights into filament organization.

The LMNA gene encodes the A-type lamins, which polymerize into ∼3.5-nm-thick filaments and, together with B-type lamins and associated proteins, form the nuclear lamina. Mutations in LMNA cause a wide variety of pathologies. In this study, we analyzed the nuclear lamina of embryonic fibroblasts from LmnaH222P/H222P mice, which develop cardiomyopathy and muscular dystrophy. Although the organization of the lamina appeared unaltered, there were changes in chromatin and B-type lamin expression. An increase in nuclear size and consequently a relative reduction in heterochromatin near the lamina allowed for a higher resolution structural analysis of lamin filaments using cryo-electron tomography. This was most apparent when visualizing lamin filaments in situ and using a nuclear extraction protocol. Averaging of individual segments of filaments in LmnaH222P/H222P mouse fibroblasts resolved two polymers that constitute the mature filaments. Our findings provide better views of the organization of lamin filaments and the effect of a striated muscle disease-causing mutation on nuclear structure.