Brusatol attenuated proliferation and invasion induced by KRAS in differentiated thyroid cancer through inhibiting Nrf2

BACKGROUND

Poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC) can be developed from differentiated thyroid cancer, and this dedifferentiated transformation leads to poor prognosis and high mortality. The role of Nrf2 in the dedifferentiation of differentiated thyroid cancer (DTC) induced by KRAS remains unclear.

METHODS AND MATERIALS

In this study, two DTC cell lines, BCPAP and WRO, were used to evaluate the function of Nrf2 in the dedifferentiation caused by wild-type KRAS (KRAS-WT) and G12V point mutation KRAS (KRAS-G12V).

RESULTS

The overexpression of KRAS-WT and KRAS-G12V increased the proliferative and invasive ability of BCPAP and WRO cells. Aggressive morphology was observed in KRAS-WT and KRAS-G12V overexpressed WRO cells. These results suggested that overexpression of KRAS-WT or KRAS-G12V may induce dedifferentiation in DTC cells. The expression of Nrf2 was increased by KRAS-WT and KRAS-G12V in DTC cells. In addition, compared with normal thyroid tissues, the expression of Nrf2 protein was considerably higher in thyroid cancer tissues on immunohistochemistry (IHC) staining, and the increased expression of Nrf2 indicated a poor prognosis of thyroid cancer. These results indicated that Nrf2 is the KRAS downstream molecule in thyroid cancer. Functional studies showed that the Nrf2 inhibitor Brusatol counteracted the proliferative and invasive abilities induced by KRAS-WT and KRAS-G12V in BCPAP and WRO cells. In addition, the xenograft assay further confirmed that Brusatol inhibits tumor growth induced by KRAS-WT and KRAS-G12V.

CONCLUSION

Collectively, this study suggests that Nrf2 could be a promising therapeutic target in KRAS-mediated dedifferentiation of thyroid cancer.

Intelligently Quantifying the Entire Irregular Dental Structure

Quantitative analysis of irregular anatomical structures is crucial in oral medicine, but clinicians often typically measure only several representative indicators within the structure as references. Deep learning semantic segmentation offers the potential for entire quantitative analysis. However, challenges persist, including segmentation difficulties due to unclear boundaries and acquiring measurement landmarks for clinical needs in entire quantitative analysis. Taking the palatal alveolar bone as an example, we proposed an artificial intelligence measurement tool for the entire quantitative analysis of irregular dental structures. To expand the applicability, we have included lightweight networks with fewer parameters and lower computational demands. Our approach finally used the lightweight model LU-Net, addressing segmentation challenges caused by unclear boundaries through a compensation module. Additional enamel segmentation was conducted to establish a measurement coordinate system. Ultimately, we presented the entire quantitative information within the structure in a manner that meets clinical needs. The tool achieved excellent segmentation results, manifested by high Dice coefficients (0.934 and 0.949), intersection over union (0.888 and 0.907), and area under the curve (0.943 and 0.949) for palatal alveolar bone and enamel in the test set. In subsequent measurements, the tool visualizes the quantitative information within the target structure by scatter plots. When comparing the measurements against representative indicators, the tool's measurement results show no statistically significant difference from the ground truth, with small mean absolute error, root mean squared error, and errors interval. Bland-Altman plots and intraclass correlation coefficients indicate the satisfactory agreement compared with manual measurements. We proposed a novel intelligent approach to address the entire quantitative analysis of irregular image structures in the clinical setting. This contributes to enabling clinicians to swiftly and comprehensively grasp structural features, facilitating the design of more personalized treatment plans for different patients, enhancing clinical efficiency and treatment success rates in turn.

Networks of Limited-Valency Patchy Particles

Equilibrium gels provide physically attractive counterparts of nonequilibrium gels, allowing statistical understanding and design of the equilibrium gel structure. Here, we assemble two-dimensional equilibrium gels from limited-valency "patchy" colloidal particles and follow their evolution at the particle scale to elucidate cluster-size distributions and free energies. By finely adjusting the patch attraction with critical Casimir forces, we let a mixture of two-valent and pseudo-three-valent patchy particles approach the percolated network state through a set of equilibrium states. Comparing this equilibrium route with a deep quench, we find that both routes approach the percolated state via the same equilibrium states, revealing that the network topology is uniquely set by the particle bond angles, independent of the formation history. The limited-valency system follows percolation theory remarkably well, approaching the percolation point with the expected universal exponents.

The association between anterior cruciate ligament degeneration and incident knee osteoarthritis: Data from the osteoarthritis initiative

Background

Though anterior cruciate ligament (ACL) tear has been widely accepted as an important accelerator for knee osteoarthritis (KOA), the role of intrinsic ACL degeneration in developing KOA has not been fully investigated.

Purpose

To determine whether ACL degeneration, in the absence of ACL tear, is associated with incident KOA over 4 years.

Study design

Cohort study; Level of evidence, 2.

Methods

Participants' knees in this nested case-control study were selected from the Osteoarthritis Initiative (OAI) study, with Kellgren-Lawrence grading (Kellgren-Lawrence grading) of 0 or 1 ​at baseline (BL). Case knees which had incident KOA (KLG ≥2) over 4 years, were matched 1:1 with control knees by gender, age and radiographic status. ACL signal intensity alteration (0-3 scale) and volume were assessed as compositional feature and morphology of ACL degeneration, using knee MRI at P0 (time of onset of incident KOA), P-1 (1 year prior to P0) and baseline. Conditional logistic regression was applied to analyze the association between measures of ACL degeneration and incident KOA.

Results

337 case knees with incident KOA were matched to 337 control knees. Participants were mostly female (68.5%), with an average age of 59.9 years old. ACL signal intensity alterations at BL, P-1 and P0 were significantly associated with an increased odds of incident KOA respectively (all P for trend ≤0.001). In contrast, ACL volumes were not significantly associated with incident KOA at any time points.

Conclusions

ACL signal intensity alteration is associated with increased incident KOA over 4 years, whereas ACL volume is not.The translational potential of this article: This paper focused on ACL signal intensity alteration which could better reflect ACL degeneration rather than ACL tear during the progression of KOA and explored this topic in a nested case-control study. Utilizing MR images from KOA participants, we extracted the imaging features of ACL. In addition, we established a semi-quantitative score for ACL signal intensity alteration and found a significant correlation between it and KOA incidence. Our findings confirmed that the more severe the ACL signal intensity alteration, the stronger relationship with the occurrence of KOA. This suggests that more emphasis should be placed on ACL degeneration rather than ACL integrity in the future.

Line Laser Scanning Combined with Machine Learning for Fish Head Cutting Position Identification

Fish head cutting is one of the most important processes during fish pre-processing. At present, the identification of cutting positions mainly depends on manual experience, which cannot meet the requirements of large-scale production lines. In this paper, a fast and contactless identification method of cutting position was carried out by using a constructed line laser data acquisition system. The fish surface data were collected by a linear laser scanning sensor, and Principal Component Analysis (PCA) was used to reduce the dimensions of the dorsal and abdominal boundary data. Based on the dimension data, Least Squares Support Vector Machines (LS-SVMs), Particle Swarm Optimization-Back Propagation (PSO-BP) networks, and Long and Short Term Memory (LSTM) neural networks were applied for fish head cutting position identification model establishment. According to the results, the LSTM model was considered to be the best prediction model with a determination coefficient (R2) value, root mean square error (RMSE), mean absolute error (MAE), and residual predictive deviation (RPD) of 0.9480, 0.2957, 0.1933, and 3.1426, respectively. This study demonstrated the reliability of combining line laser scanning techniques with machine learning using LSTM to identify the fish head cutting position accurately and quickly. It can provide a theoretical reference for the development of intelligent processing and intelligent cutting equipment for fish.

GRSF1 antagonizes age-associated hypercoagulability via modulation of fibrinogen mRNA stability

Age-associated hypercoagulability is accompanied by the increase of plasma levels of some coagulation factors including fibrinogen which may contribute to the increased risk of cardiovascular, cerebrovascular, and thrombotic diseases in elderly people. However, the underlying mechanism of increased plasma fibrinogen concentration during aging is still elusive. GRSF1 belongs to the heterogeneous nuclear ribonucleoproteins F/H (hnRNP F/H) subfamily. Here, we report that GRSF1 attenuates hypercoagulability via negative modulation of fibrinogen expression. We demonstrated that GRSF1 negatively regulated fibrinogen expression at both mRNA and protein levels. GRSF1 directly interacted with the coding region (CDS) of FGA, FGB, and FGG mRNAs, and decreased their stability thus mitigating fibrinogen expression. We further identified that only a few G-tracts within the Fib C domain of FGA, FGB, and FGG CDS and the qRRM2 domain of GRSF1 were required for their interaction. Moreover, we confirmed hypercoagulability and the decrease of GRSF1 expression level during mice aging. Functionally, GRSF1 overexpression in old mice liver decreased fibrinogen plasma level, reduced hypercoagulability, and mitigated blood coagulation activity, whereas GRSF1 knockdown in young mice liver increased fibrinogen plasma level and promoted blood coagulation activity. Collectively, our findings unveil a novel posttranscriptional regulation of fibrinogen by GRSF1 and uncover a critical role of GRSF1 in regulating blood coagulation activity.

Ablation of the gut microbiota alleviates high-methionine diet-induced hyperhomocysteinemia and glucose intolerance in mice

A high-methionine (HM) diet leads to hyperhomocysteinemia (HHcy), while gastrointestinal tissue is an important site of net homocysteine (Hcy) production. However, the role of the gut microbiota in host HHcy remains obscure. This study aimed to determine whether gut microbiota ablation could alleviate host HHcy and glucose intolerance and reveal the underlying mechanism. The results showed that the HM diet-induced HHcy and glucose intolerance in mice, while antibiotic administration decreased the plasma level of Hcy and reversed glucose intolerance. HM diet increased intestinal epithelial homocysteine levels, while antibiotic treatment decreased intestinal epithelial homocysteine levels under the HM diet. Gut microbiota depletion had no effect on the gene expression and enzyme activity of CBS and BHMT in the livers of HM diet-fed mice. The HM diet altered the composition of the gut microbiota with marked increases in the abundances of Faecalibaculum and Dubosiella, which were also positively correlated with plasma Hcy concentrations. An in-depth analysis of the bacterial cysteine and methionine metabolism pathways showed that the abundances of two homocysteine biosynthesis-related KEGG orthologies (KOs) were markedly increased in the gut microbiota in HM diet-fed mice. Hcy was detected from Dubosiella newyorkensis-cultured supernatant by liquid chromatography-tandem mass spectrometry (LC‒MS) analysis. In conclusion, these findings suggested that the HM diet-induced HHcy and glucose intolerance in mice, by reshaping the composition of the gut microbiota, which might produce and secrete Hcy.

Targeting cytokine-like protein FAM3D lowers blood pressure in hypertension

Current antihypertensive options still incompletely control blood pressure, suggesting the existence of uncovered pathogenic mechanisms. Here, whether cytokine-like protein family with sequence similarity 3, member D (FAM3D) is involved in hypertension etiology is evaluated. A case-control study exhibits that FAM3D is elevated in patients with hypertension, with a positive association with odds of hypertension. FAM3D deficiency significantly ameliorates angiotensin II (AngII)-induced hypertension in mice. Mechanistically, FAM3D directly causes endothelial nitric oxide synthase (eNOS) uncoupling and impairs endothelium-dependent vasorelaxation, whereas 2,4-diamino-6-hydroxypyrimidine to induce eNOS uncoupling abolishes the protective effect of FAM3D deficiency against AngII-induced hypertension. Furthermore, antagonism of formyl peptide receptor 1 (FPR1) and FPR2 or the suppression of oxidative stress blunts FAM3D-induced eNOS uncoupling. Translationally, targeting endothelial FAM3D by adeno-associated virus or intraperitoneal injection of FAM3D-neutralizing antibodies markedly ameliorates AngII- or deoxycorticosterone acetate (DOCA)-salt-induced hypertension. Conclusively, FAM3D causes eNOS uncoupling through FPR1- and FPR2-mediated oxidative stress, thereby exacerbating the development of hypertension. FAM3D may be a potential therapeutic target for hypertension.

Chemo-mechanical diffusion waves explain collective dynamics of immune cell podosomes

Immune cells, such as macrophages and dendritic cells, can utilize podosomes, mechanosensitive actin-rich protrusions, to generate forces, migrate, and patrol for foreign antigens. Individual podosomes probe their microenvironment through periodic protrusion and retraction cycles (height oscillations), while oscillations of multiple podosomes in a cluster are coordinated in a wave-like fashion. However, the mechanisms governing both the individual oscillations and the collective wave-like dynamics remain unclear. Here, by integrating actin polymerization, myosin contractility, actin diffusion, and mechanosensitive signaling, we develop a chemo-mechanical model for podosome dynamics in clusters. Our model reveals that podosomes show oscillatory growth when actin polymerization-driven protrusion and signaling-associated myosin contraction occur at similar rates, while the diffusion of actin monomers drives wave-like coordination of podosome oscillations. Our theoretical predictions are validated by different pharmacological treatments and the impact of microenvironment stiffness on chemo-mechanical waves. Our proposed framework can shed light on the role of podosomes in immune cell mechanosensing within the context of wound healing and cancer immunotherapy.

Urate-Lowering Therapy Inhibits Thoracic Aortic Aneurysm and Dissection Formation in Mice

BACKGROUND

Thoracic aortic aneurysm and dissection (TAAD) is a highly lethal vascular disease without effective drug therapy. Whether elevated serum concentrations of uric acid are involved in TAAD development remains unclear.

METHODS

Serum uric acid levels were detected in different TAAD mouse models and patients. The urate-lowering drug allopurinol was administered in the drinking water of TAAD mice. Adenine diet-induced mice were established to investigate the role of hyperuricemia in TAAD formation and RNA-sequencing of thoracic aortas from these mice was performed.

RESULTS

We found serum uric acid levels were elevated in various mouse TAAD models, including mice fed a β-aminopropionitrile diet, Marfan mice with fibrillin-1 haploinsufficiency (Fbn1^C1041G/+), and ApoE^-/- mice infused with Ang II (angiotensin II), as well as in patients with TAAD. Administration of urate-lowering drug allopurinol in the drinking water significantly alleviated TAAD formation in β-aminopropionitrile-treated mice, Fbn1^C1041G/+ mice, and Ang II-infused ApoE^-/- mice. Moreover, an adenine diet was used to induce hyperuricemia in mice. Intriguingly, a 4-week adenine diet feeding directly induced TAAD formation characterized by increased maximal thoracic aortic diameters and severe elastin degradation, which were ameliorated by allopurinol. Unbiased RNA-sequencing in mouse thoracic aortas suggested that FcγR (Fc gamma receptor) was upregulated upon adenine diet, but reciprocally repressed by allopurinol. Mechanistically, hyperuricemia activated FcγR-mediated ERK1/2 (extracellular signal-regulated kinase 1/2) phosphorylation to induce macrophage inflammation and TAAD development, which was abrogated by allopurinol or FcγR deficiency.

CONCLUSIONS

This study uncovered an important and previously unrecognized role of hyperuricemia in mediating the pathogenesis of TAAD, and uric acid-lowering drug may represent a promising therapeutic approach for TAAD.

Activin Receptor-Like Kinase 3 Directly Couples Gαq (Guanine Nucleotide-Binding Protein Subunit αq)/ Gαq (Guanine Nucleotide-Binding Protein Subunit α11) to Regulate Vascular Contractility

BACKGROUND

Vascular smooth muscle cell (VSMC) contractility is critical for blood pressure regulation and vascular homeostasis. Identifying the key molecule that maintains VSMC contractility may provide a novel therapeutic target for vascular remodeling. ALK3 (activin receptor-like kinase 3) is a serine/threonine kinase receptor, and deletion of ALK3 causes embryonic lethality. However, little is known about the role of ALK3 in postnatal arterial function and homeostasis.

METHODS

We conducted in vivo studies in a tamoxifen-induced postnatal VSMC-specific ALK3 deletion mice suitable for analysis of blood pressure and vascular contractility. Additionally, the role of ALK3 on VSMC was determined using Western blot, collagen-based contraction assay and traction force microscopy. Furthermore, interactome analysis were performed to identify the ALK3-associated proteins and bioluminescence resonance energy transfer assay was used to characterize Gαq activation.

RESULTS

ALK3 deficiency in VSMC led to spontaneous hypotension and impaired response to angiotensin II in mice. In vivo and in vitro data revealed that ALK3 deficiency impaired contraction force generation by VSMCs, repressed the expression of contractile proteins, and inhibited the phosphorylation of myosin light chain. Mechanistically, Smad1/5/8 signaling mediated the ALK3-modulated contractile protein expressions but not myosin light chain phosphorylation. Furthermore, interactome analysis revealed that ALK3 directly interacted with and activated Gαq (guanine nucleotide-binding protein subunit αq)/Gα11 (guanine nucleotide-binding protein subunit α11), thereby stimulating myosin light chain phosphorylation and VSMC contraction.

CONCLUSIONS

Our study revealed that in addition to canonical Smad1/5/8 signaling, ALK3 modulates VSMC contractility through direct interaction with Gαq/Gα11, and therefore, might serve as a potential target for modulating aortic wall homeostasis.

Electrical impedance myography combined with quantitative assessment techniques in paretic muscle of stroke survivors: Insights and challenges

Aging is a non-modifiable risk factor for stroke and the global burden of stroke is continuing to increase due to the aging society. Muscle dysfunction, common sequela of stroke, has long been of research interests. Therefore, how to accurately assess muscle function is particularly important. Electrical impedance myography (EIM) has proven to be feasible to assess muscle impairment in patients with stroke in terms of micro structures, such as muscle membrane integrity, extracellular and intracellular fluids. However, EIM alone is not sufficient to assess muscle function comprehensively given the complex contributors to paretic muscle after an insult. This article discusses the potential to combine EIM and other common quantitative methods as ways to improve the assessment of muscle function in stroke survivors. Clinically, these combined assessments provide not only a distinct advantage for greater accuracy of muscle assessment through cross-validation, but also the physiological explanation on muscle dysfunction at the micro level. Different combinations of assessments are discussed with insights for different purposes. The assessments of morphological, mechanical and contractile properties combined with EIM are focused since changes in muscle structures, tone and strength directly reflect the muscle function of stroke survivors. With advances in computational technology, finite element model and machine learning model that incorporate multi-modal evaluation parameters to enable the establishment of predictive or diagnostic model will be the next step forward to assess muscle function for individual with stroke.

ADAMTS-7 deficiency attenuates thoracic aortic aneurysm and dissection in mice

Thoracic aortic aneurysm and dissection (TAAD) is a life-threatening cardiovascular disease with severe extracellular matrix (ECM) remodeling that lacks efficient early stage diagnosis and nonsurgical therapy. A disintegrin and metalloproteinase with thrombospondin motif 7 (ADAMTS-7) is recognized as a novel locus for human coronary artery atherosclerosis. Previous work by us and others showed that ADAMTS-7 promoted atherosclerosis, postinjury neointima formation, and vascular calcification. However, whether ADAMTS-7 is involved in TAAD pathogenesis is unknown. We aimed to explore the alterations in ADAMTS-7 expression in human and mouse TAAD, and investigate the role of ADAMTS-7 in TAAD formation. A case-control study of TAAD patients (N = 86) and healthy participants (N = 88) was performed. The plasma ADAMTS-7 levels were markedly increased in TAAD patients within 24 h and peaked in 7 days. A TAAD mouse model was induced with 0.5% β-aminopropionitrile (BAPN) in drinking water. ELISA analysis of mouse plasma, Western blotting, and immunohistochemical staining of aorta showed an increase in ADAMTS-7 in the early stage of TAAD. Moreover, ADAMTS-7-deficient mice exhibited significantly attenuated TAAD formation and TAAD rupture-related mortality in both male and female mice, which was accompanied by reduced artery dilation and inhibited elastin degradation. ADAMTS-7 deficiency caused repressed inflammatory response and complement system activation during TAAD formation. An increase in plasma ADAMTS-7 is a novel biomarker for human TAAD. ADAMTS-7 deficiency attenuates BAPN-induced murine TAAD. ADAMTS-7 is a potential novel target for TAAD diagnosis and therapy. KEY MESSAGES: A case-control study revealed increased plasma ADAMTS-7 is a risk factor for TAAD. ADAMTS-7 was elevated in plasma and aorta at early stage of mouse TAAD. ADAMTS-7 knockout attenuated mouse TAAD formation and mortality in both sexes.

The Association Between Quadriceps Strength and Synovitis in Knee Osteoarthritis: An Exploratory Study From the Osteoarthritis Initiative

OBJECTIVE

The aim of this study was to explore the association between quadriceps strength and synovitis in knee osteoarthritis (KOA).

METHODS

This study was derived from the Osteoarthritis Initiative (OAI), which recruited adults from the OAI cohort with or at risk of KOA. Knees with complete records of isometric quadriceps strength and effusion-synovitis and Hoffa-synovitis assessments were included. Quadriceps strength was measured isometrically at baseline. Effusion-synovitis and Hoffa-synovitis were measured using the Magnetic Resonance Imaging Osteoarthritis Knee Score at baseline and at 1-year and 2-year follow-ups. Generalized estimating equations were used to analyze the associations of baseline quadriceps strength with changes in effusion-synovitis and Hoffa-synovitis in multivariable analyses. Additionally, analyses were stratified by synovitis-driven inflammatory phenotypes.

RESULTS

A total of 1513 knees were included in this study. In total, 61% of the subjects were female; subjects had an average age of 61.9 (SD 8.8) years and a mean BMI of 29.4 (SD 4.7). Regarding the whole population, baseline quadriceps strength was negatively associated with baseline effusion-synovitis and follow-up changes in effusion-synovitis (odds ratio [OR] 0.77-0.86), but no significant association was observed in terms of Hoffa-synovitis. Stratified by synovitis-driven inflammatory phenotype, baseline quadriceps strength was significantly associated with follow-up changes in effusion-synovitis-but not in Hoffa-synovitis-in the population with existing effusion-synovitis (OR 0.75-0.79).

CONCLUSION

Higher baseline quadriceps strength was negatively associated with changes in effusion-synovitis-but not in Hoffa-synovitis-especially in the population with existing effusion-synovitis. Our findings suggested a potential protective role of the quadriceps in effusion-synovitis.

Characterization and differentiation of pollen lipidomes and proteomes from different intrafloral stamens in heterantherous Senna bicapsularis

Numerous compounds in pollen can affect the foraging decision-making of bees. Clarification of phytochemical components and identification of key substances for bee foraging preference in pollen are essential steps for apiculture and developing a conservation strategy. Senna bicapsularis, a heterantherous plant that possesses three different stamen types in the same flower, among which bees forage selectively, provides us with an ideal research model for identification of potential substances of bee foraging preference. The lipid and protein compositions of pollen from the anthers of different stamens of S. bicapsularis were investigated and compared. The polyunsaturated fatty acids (PUFAs) and monounsaturated FAs (MUFAs) were highest among lipid molecules in pollen from short (S) stamens than from long (L) and medium (M) stamens. This result is consistent with the FA content measurement, showing the highest FAs and UFAs content in S pollen, especially α-linolenic acid. We inferred that α-linolenic acid might be one of the key substances for bee foraging preference in pollen. Moreover, proteomic analysis showed that several differentially expressed proteins involved in lipid biosynthesis were highly accumulated in S pollen, such as choline kinase 2, 3-oxoacyl-ACP synthase-like protein and choline/ethanolamine phosphotransferase 1, in line with the highest FA content of S pollen. Additionally, DEPs involved in 'starch and sucrose metabolism', 'phenylpropanoid biosynthesis' and 'cyanoamino acid metabolism' were more represented in S compared with L and M pollen. The study suggests that differences in proteomic and lipidomic profiling among the three different stamen types might affect foraging decision-making of bumblebees.

MRI-based Texture Analysis of Infrapatellar Fat Pad to Predict Knee Osteoarthritis Incidence

Background Infrapatellar fat pad (IPFP) quality has been implicated as a marker for predicting knee osteoarthritis (KOA); however, no valid quantification for subtle IPFP abnormalities has been established. Purpose To investigate whether MRI-based three-dimensional texture analysis of IPFP abnormalities could help predict incident radiographic KOA. Materials and Methods In this prospective nested case-control study, 690 participants whose knees were at risk for KOA were included from the Pivotal Osteoarthritis Initiative MRI Analyses incident osteoarthritis cohort. All knees had a Kellgren-Lawrence grade of 1 or less at baseline. During the 4-year follow-up, case participants were matched 1:1 to control participants, with incident radiographic KOA as the outcome. MRI scans were segmented at the incident time point of KOA (hereafter, P0), 1 year before P0 (hereafter, P-1), and baseline. MRI-based three-dimensional texture analysis was performed to extract IPFP texture features. Least absolute shrinkage and selection operator and multivariable logistic regressions were applied in the development cohort and evaluated in the test cohort. The area under the receiver operating characteristic curve (AUC) was used to evaluate the discriminative value of the clinical score, IPFP texture score, and MRI Osteoarthritis Knee Score. Results Participants were allocated to development (n = 500, 340 women; mean age, 60 years) and test (n = 190, 120 women; mean age, 61 years) cohorts. In both cohorts, IPFP texture scores (AUC ≥0.75 for all) showed greater discrimination than clinical scores (AUC ≤0.69 for all) at baseline, P-1, and P0, with significant differences in pairwise comparisons (P ≤ .002 for all). Greater predictive and concurrent validities of IPFP texture scores (AUC ≥0.75 for all) compared with MRI Osteoarthritis Knee Scores (AUC ≤0.66 for all) were also demonstrated (P < .001 for all). Conclusion MRI-based three-dimensional texture of the infrapatellar fat pad was associated with future development of knee osteoarthritis. ClinicalTrials.gov registration no.: NCT00080171 © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Fischer in this issue.

Quadriceps strength is negatively associated with knee joint structural abnormalities-data from osteoarthritis initiative

OBJECTIVE

The aim of this study was to explore the longitudinal associations between baseline quadriceps strength and knee joint structural abnormalities in knee osteoarthritis (KOA).

METHODS

This study is a longitudinally observational study based on Osteoarthritis Initiative (OAI) cohort, including men and women aged 45-79. Quadriceps strength was measured by isometric knee extension testing at baseline. Knee joint structural abnormalities, including cartilage damage, bone marrow lesions (BMLs), effusion-synovitis and Hoffa-synovitis, were evaluated by Magnetic Resonance Imaging Osteoarthritis Knee Score (MOAKS) at baseline and 1-year follow-up. Generalized estimating equations were employed to examine the associations between quadriceps strength and knee structural abnormalities. All analyses were stratified by sex.

RESULTS

One thousand three hundred thirty-eight participants (523 men and 815 women) with a mean age of 61.8 years and a mean BMI of 29.4 kg/m² were included in this study. For men, no significantly longitudinal association of quadriceps strength with structural abnormalities was detected. In contrast, quadriceps strength was significantly and negatively associated with changes in cartilage damage and BMLs in lateral patellofemoral joint (PFJ) (cartilage damage: OR: 0.91, 95% CI 0.84 to 0.99, P = 0.023; BMLs: OR: 0.85, 95% CI 0.74 to 0.96, P = 0.011) and effusion-synovitis (OR = 0.88, 95% CI 0.78 to 0.99, P = 0.045) among females longitudinally. Higher quadriceps strength was significantly associated with less progression of lateral PFJ cartilage damage, BMLs and effusion-synovitis in females.

CONCLUSIONS

Higher quadriceps strength was associated with changes in cartilage damage and BMLs within the lateral PFJ and effusion-synovitis among females, suggesting the potential protective role of quadriceps strength on joint structures in women.

Pain-Related Risk Factors Among Radiologic Stages of Knee Osteoarthritis: Data From the Osteoarthritis Initiative

OBJECTIVE

To investigate whether risk factors related to pain vary at different stages of knee osteoarthritis (OA).

METHODS

Individuals from the Osteoarthritis Initiative with available Kellgren/Lawrence (K/L) grade and numerical rating scale (NRS) data at baseline were included in this study. Pain severity was classified into 3 categories based on NRS scores: no pain, mild pain, and moderate/severe pain. Knee OA severity was stratified into 4 categories according to the K/L system. Pain risk factors were evaluated using generalized ordinal logistic regression analysis, and a heatmap was created to compare differences in standardized regression coefficients between subgroups of patients with different knee OA severities.

RESULTS

A total of 4,446 subjects were included in this study: 1,574 individuals without pain (35.4%), 1,138 individuals with mild pain (25.6%), and 1,734 individuals with moderate/severe pain (39.0%). For the entire population and subjects in the premorbid-stage subgroup, knee injury history, diabetes mellitus, depression, use of nonsteroidal anti-inflammatory drugs (NSAIDs), and valgus malaligned knees were associated with more severe pain. Older age and stronger quadriceps muscles were associated with milder pain. As the disease progressed, the number of significant risk factors decreased. Only age and quadriceps muscle force remained significant in end-stage disease.

CONCLUSION

Multiple factors are associated with pain in patients with knee OA. As the disease progresses, the number of significant risk factors gradually reduces. These findings suggest that strategies for managing pain related to knee OA should vary depending on radiographic grades.

CARBONATED BEVERAGES AFFECT LEVELS OF ANDROGEN RECEPTOR AND TESTOSTERONE SECRETION IN MICE

Objectives

This work aimed to study the influences of carbonated beverages (CBs) on the testis growth and the expression levels of androgen receptor (AR) of mice.

Methods

Two experimental groups of 30 mice each PEP-1 and PEP-2 drank 50% and 100% Pepsi-Cola, respectively for 15 days. Other 2 experimental groups of 30 mice each COC-1 and COC-2 drank 50% and 100% Coca-Cola, respectively for 15 days. The control group (CG) of 30 mice drank water. Bilateral testes were harvested aseptically on days 0, 5, 7, 10, 13 and 15. Real-time PCR and Western blot were implemented to detect levels of androgen receptor (AR) mRNA and protein in testis tissues.

Results

Testes masses of PEP-2, COC-1 and COC-2 were greater than those of PEP-1 and CG (P < 0.05). On day 15, testis longitudinal diameter (TLD) of CBs-treated mice was increased as compared to CG. TLD, testes transverse diameters (TTD) and AR proteins levels of PEP-2 and COC-2 were increased in comparison with CG (P<0.05). Serum testosterone concentrations of PEP-2 were higher than that of COC-1 and CG (P < 0.05). Levels of AR mRNAs of four CBs-treated mice were increased by 60.18%, 67.26%, 65.93% and 78.76%.

Conclusions

A high concentration of Coca-Cola and Pepsi-Cola could raise TLD and TDD, enhance testosterone secretion, and increase serum EGF concentrations.

P-382 Decrease of serum estradiol prior to human chorionic gonadotrophin administration have an impact on live birth in IVF/ICSI cycles

Study question

Whether decrease of serum estradiol prior to human chorionic gonadotrophin administration have an impact on live birth in IVF/ICSI cycles?

Summary answer

The E2 change before the day of hCG administration had significant correlation with live birth. The live birth rate decreased with decreasing serum E2 level.

What is known already

The objective of this study was to assess the effects of a decrease of estradiol (E2) levels on the day of human chorionic gonadotrophin (hCG) administration on in vitro fertilization /intracytoplasmic sperm injection (IVF/ICSI) outcomes, including cycles with long, antagonist and micro stimulus protocols.

Study design, size, duration

In this retrospective cohort study, 1303 patients who received IVF/ICSI non-donor treatment were identified. Patients were divided into two groups according to live birth and the characteristics of IVF/ICSI cycles were compared between groups, including baseline infertility parameters, ovarian stimulation characteristics and embryo laboratory manipulation parameters.

Participants/materials, setting, methods

In this retrospective cohort study, 1303 patients who received IVF/ICSI non-donor treatment were identified. Patients were divided into two groups according to live birth and the characteristics of IVF/ICSI cycles were compared between groups, including baseline infertility parameters, ovarian stimulation characteristics and embryo laboratory manipulation parameters. The multivariate logistic regression model was performed to adjust potential confounders and assess correlation between E2 dynamics before hCG administration and live birth.

Main results and the role of chance

Our results revealed that patients without live birth had higher age (32.13 ± 4.33 vs. 30.21 ± 3.71, P &lt; 0.001) and pervious miscarriages (0.57 ± 0.95 vs. 0.46 ± 0.83, P = 0.0295), while had lower number of oocytes retrieved (8.95 ± 4.69 vs. 12.36 ± 5.54, P &lt; 0.001), day of hCG E2 (8269.53 ± 4104.22 vs. 9580.71 ± 3534.11, P &lt; 0.001) and endometrium thickness (10.37 ± 3.66 vs. 11.50 ± 3.40, P &lt; 0.001) compared with patients with live birth. Additionally, the multivariate logistic regression analysis displayed significant impact of serum E2 change on the live birth, and the achievement of live birth [OR (95%CI) 0.81 (0.71, 0.92), P = 0.001] decreased with the decreasing level of serum E2 before hCG trigger day. Estradiol stratification analyses displayed the OR and 95% CI for the association between △E2 and live birth among patients with different levels of estradiol decline (&lt;25%, 25%–50%, 50%–75%, &gt;75%). Compared with the &lt;25% decline and 25%–50% decline groups, the ORs of 50%–75% and &gt;75% decline groups were 1.66 (95% CI: 1.12-2.45, P = 0.012) and 2.00 (95% CI: 1.39-2.89, P &lt; 0.001), respectively, after adjusting potential confounders.

Limitations, reasons for caution

There was concealment of randomization and blinding of outcome assessments reducing the risk of selection and measurement bias.

Wider implications of the findings

In summary, the E2 change before the day of hCG administration had significant correlation with live birth, and the live birth decreased with the decreasing level of serum E2 before hCG trigger day. The patients with a greater decline in the E2 level more likely to had poor clinical outcomes.

Trial registration number

Chi CTR1900026088

Exogenous melatonin prevents type 1 diabetes mellitus-induced bone loss, probably by inhibiting senescence

Exogenous melatonin inhibited the senescence of preosteoblast cells in type 1 diabetic (T1D) mice and those cultured in high glucose (HG) by multiple regulations. Exogenous melatonin had a protective effect on diabetic osteoporosis, which may depend on the inhibition of senescence.

INTRODUCTION

Senescence is thought to play an important role in the pathophysiological mechanisms underlying diabetic bone loss. Increasing evidence has shown that melatonin exerts anti-senescence effects. In this study, we investigated whether melatonin can inhibit senescence and prevent diabetic bone loss.

METHODS

C57BL/6 mice received a single intraperitoneal injection of 160 mg/kg streptozotocin, followed by the oral administration of melatonin or vehicle for 2 months. Then, tissues were harvested and subsequently examined. MC3T3-E1 cells were cultured under HG conditions for 7 days and then treated with melatonin or not for 24 h. Sirt1-specific siRNAs and MT1- or MT2-specific shRNA plasmids were transfected into MC3T3-E1 cells for mechanistic study.

RESULTS

The total protein extracted from mouse femurs revealed that melatonin prevented senescence in T1D mice. The micro-CT results indicated that melatonin prevented bone loss in T1D mice. Cellular experiments indicated that melatonin administration prevented HG-induced senescence, whereas knockdown of the melatonin receptors MT1 or MT2 abolished these effects. Sirt1 expression was upregulated by melatonin administration but significantly reduced after MT1 or MT2 was knocked down. Knockdown of Sirt1 blocked the anti-senescence effects of melatonin. Additionally, melatonin promoted the expression of CDK2, CDK4, and CyclinD1, while knockdown of MT1 or MT2 abolished these effects. Furthermore, melatonin increased the expression of the polycomb repressive complex (PRC), but knockdown of MT1 or MT2 abolished these effects. Furthermore, melatonin increased the protein levels of Sirt1, PRC1/2 complex-, and cell cycle-related proteins.

CONCLUSION

This work shows that melatonin protects against T1D-induced bone loss, probably by inhibiting senescence. Targeting senescence in the investigation of diabetic osteoporosis may lead to novel discoveries.

Large Culprit Plaque and More Intracranial Plaques Are Associated with Recurrent Stroke: A Case-Control Study Using Vessel Wall Imaging

BACKGROUND AND PURPOSE

Intracranial atherosclerotic plaque features are potential factors associated with recurrent stroke, but previous studies only focused on a single lesion, and few studies investigated them with perfusion impairment. This study aimed to investigate the association among whole-brain plaque features, perfusion deficit, and stroke recurrence.

MATERIALS AND METHODS

Patients with ischemic stroke due to intracranial atherosclerosis were retrospectively collected and categorized into first-time and recurrent-stroke groups. Patients underwent high-resolution vessel wall imaging and DSC-PWI. Intracranial plaque number, culprit plaque features (such as plaque volume/burden, degree of stenosis, enhancement ratio), and perfusion deficit variables were recorded. Logistic regression analyses were performed to determine the independent factors associated with recurrent stroke.

RESULTS

One hundred seventy-five patients (mean age, 59 [SD, 12] years; 115 men) were included. Compared with the first-time stroke group (n = 100), the recurrent-stroke group (n = 75) had a larger culprit volume (P = .006) and showed more intracranial plaques (P < .001) and more enhanced plaques (P = .003). After we adjusted for other factors, culprit plaque volume (OR, 1.16 per 10-mm³ increase; 95% CI, 1.03-1.30; P = .015) and total plaque number (OR, 1.31; 95% CI, 1.13-1.52; P < .001) were independently associated with recurrent stroke. Combining these factors increased the area under the curve to 0.71.

CONCLUSIONS

Large culprit plaque and more intracranial plaques were independently associated with recurrent stroke. Performing whole-brain vessel wall imaging may help identify patients with a higher risk of recurrent stroke.

A 2-year locomotive exploration and scientific investigation of the lunar farside by the Yutu-2 rover

The lunar nearside has been investigated by many uncrewed and crewed missions, but the farside of the Moon remains poorly known. Lunar farside exploration is challenging because maneuvering rovers with efficient locomotion in harsh extraterrestrial environment is necessary to explore geological characteristics of scientific interest. Chang'E-4 mission successfully targeted the Moon's farside and deployed a teleoperated rover (Yutu-2) to explore inside the Von Kármán crater, conveying rich information regarding regolith, craters, and rocks. Here, we report mobile exploration on the lunar farside with Yutu-2 over the initial 2 years. During its journey, Yutu-2 has experienced varying degrees of mild slip and skid, indicating that the terrain is relatively flat at large scales but scattered with local gentle slopes. Cloddy soil sticking on its wheels implies a greater cohesion of the lunar soil than encountered at other lunar landing sites. Further identification results indicate that the regolith resembles dry sand and sandy loam on Earth in bearing properties, demonstrating greater bearing strength than that identified during the Apollo missions. In sharp contrast to the sparsity of rocks along the traverse route, small fresh craters with unilateral moldable ejecta are abundant, and some of them contain high-reflectance materials at the bottom, suggestive of secondary impact events. These findings hint at notable differences in the surface geology between the lunar farside and nearside. Experience gained with Yutu-2 improves the understanding of the farside of the Moon, which, in return, may lead to locomotion with improved efficiency and larger range.

[Gut microbiome composition in pre-adolescent children with different meat consumption patterns]

OBJECTIVE

To compare the composition of gut microbiome in pre-adolescent children with different meat consumption patterns.

METHODS

This study was conducted among 44 healthy school-age children (age range 8-10 years) in Shenzhen. According to the monthly intake frequency ratio of white meat and red meat, the children were divided into red-meat group (n=15), balanced group (n=16) and white-meat group (n=13). The Food Frequency Questionnaire (FFQ) was used to investigate the children's diet, and samples of morning feces were collected to study the gut microbiome. The fecal DNA was extracted and amplified, and the composition of the intestinal microbiome of the children was analyzed using Illumina Miseq high-throughput sequencing.

RESULTS

The children in red meat and white meat groups showed significantly lower abundance and diversity of gut microbiota than those with a balanced diet (P < 0.05). LEfSe analysis of the genus in the fecal samples showed that Escherichia-Shigella, Coprobacillus and Peptoniphilus were enriched in red-meat group and Holdemanella was enriched in the white-meat group as compared with the balanced group. In the samples of the balanced group, 31 and 25 genus (such as Laurespirillum and Rumenococcus) were significantly enriched as compared with the samples of the red-meat group and the white-meat group, respectively. Prediction of the gut microbiota KEGG pathway using PICRUSt2 suggested that compared with that in the balanced group, the gut microbiota in red-meat group had significant activation of the pathways involving lipopolysaccharide biosynthesis (P < 0.01), arachidonic acid metabolism (P < 0.01), thyroid hormone synthesis (P < 0.001), and carbohydrate digestion and absorption (P < 0.05). But compared with the white-meat group, the red-meat group showed only significant activation of the pathways of arachidonic acid metabolism (P < 0.05) and thyroid hormone synthesis (P < 0.05).

CONCLUSION

The preference of red meat and white meat consumption may significantly reduce the abundance and diversity of gut microbiota in pre-adolescent children. A red meat-rich diet may cause enrichment of Escherichia-Shigella and significant activation of lipopolysaccharide biosynthesis pathway, suggesting the potential benefit of a balanced diet for pre-adolescent children.

Unspliced XBP1 Counteracts β-catenin to Inhibit Vascular Calcification

Background: Vascular calcification is a prevalent complication in chronic kidney disease and contributes to increased cardiovascular morbidity and mortality. XBP1 (X-box binding protein 1), existing as the unspliced (XBP1u) and spliced (XBP1s) forms, is a key component of the endoplasmic reticulum stress involved in vascular diseases. However, whether XBP1u participates in the development of vascular calcification remains unclear. Methods: We aim to investigate the role of XBP1u in vascular calcification.XBP1u protein levels were reduced in high phosphate (Pi)-induced calcified vascular smooth muscle cells (VSMCs), calcified aortas from mice with adenine diet-induced chronic renal failure (CRF) and calcified radial arteries from CRF patients. Results: Inhibition of XBP1u rather than XBP1s upregulated in the expression of the osteogenic markers runt-related transcription factor 2 (Runx2) and msh homeobox2 (Msx2), and exacerbated high Pi-induced VSMC calcification, as verified by calcium deposition and Alizarin red S staining. In contrast, XBP1u overexpression in high Pi-induced VSMCs significantly inhibited osteogenic differentiation and calcification. Consistently, SMC-specific XBP1 deficiency in mice markedly aggravated the adenine diet- and 5/6 nephrectomy-induced vascular calcification compared with that in the control littermates. Further interactome analysis revealed that XBP1u bound directly to β-catenin, a key regulator of vascular calcification, via aa 205-230 in its C-terminal degradation domain. XBP1u interacted with β-catenin to promote its ubiquitin-proteasomal degradation and thus inhibited β-catenin/T-cell factor (TCF)-mediated Runx2 and Msx2 transcription. Knockdown of β-catenin abolished the effect of XBP1u deficiency on VSMC calcification, suggesting a β-catenin-mediated mechanism. Moreover, the degradation of β-catenin promoted by XBP1u was independent of glycogen synthase kinase 3β (GSK-3β)-involved destruction complex. Conclusions: Our study identified XBP1u as a novel endogenous inhibitor of vascular calcification by counteracting β-catenin and promoting its ubiquitin-proteasomal degradation, which represents a new regulatory pathway of β-catenin and a promising target for vascular calcification treatment.

Enhanced substrate stress relaxation promotes filopodia-mediated cell migration

Cell migration on two-dimensional substrates is typically characterized by lamellipodia at the leading edge, mature focal adhesions and spread morphologies. These observations result from adherent cell migration studies on stiff, elastic substrates, because most cells do not migrate on soft, elastic substrates. However, many biological tissues are soft and viscoelastic, exhibiting stress relaxation over time in response to a deformation. Here, we have systematically investigated the impact of substrate stress relaxation on cell migration on soft substrates. We observed that cells migrate minimally on substrates with an elastic modulus of 2 kPa that are elastic or exhibit slow stress relaxation, but migrate robustly on 2-kPa substrates that exhibit fast stress relaxation. Strikingly, migrating cells were not spread out and did not extend lamellipodial protrusions, but were instead rounded, with filopodia protrusions extending at the leading edge, and exhibited small nascent adhesions. Computational models of cell migration based on a motor-clutch framework predict the observed impact of substrate stress relaxation on cell migration and filopodia dynamics. Our findings establish substrate stress relaxation as a key requirement for robust cell migration on soft substrates and uncover a mode of two-dimensional cell migration marked by round morphologies, filopodia protrusions and weak adhesions.

Osteoporosis is accompanied by reduced CD274 expression in human bone marrow-derived mesenchymal stem cells

Underlying pathomechanisms of osteoporosis are still not fully elucidated. Cell-based therapy approaches pose new possibilities to treat osteoporosis and its complications. The aim of this study was to quantify differences in human bone marrow-derived mesenchymal stem cells (hBMSCs) between healthy donors and those suffering from clinically manifest osteoporosis. Cell samples of seven donors for each group were selected retrospectively from the hBMSC cell bank of the Trauma Department of Hannover Medical School. Cells were evaluated for their adipogenic, osteogenic and chondrogenic differentiation potential, for their proliferation potential and expression of surface antigens. Furthermore, a RT2 Osteoporosis Profiler PCR array, as well as quantitative real-time PCR were carried out to evaluate changes in gene expression. Cultivated hBMSCs from osteoporotic donors showed significantly lower cell surface expression of CD274 (4.98 % ± 2.38 %) than those from the control group (26.03 % ± 13.39 %; p = 0.007), as assessed by flow cytometry. In osteoporotic patients, genes involved in inhibition of the anabolic WNT signalling pathway and those associated with stimulation of bone resorption were significantly upregulated. Apart from these changes, no significant differences were found for the other cell surface antigens, adipogenic, osteogenic and chondrogenic differentiation ability as well as proliferation potential. These findings supported the theory of an influence of CD274 on the regulation of bone metabolism. CD274 might be a promising target for further investigations of the pathogenesis of osteoporosis and of cell-based therapies involving MSCs.

Revealing pseudorotation and ring-opening reactions in colloidal organic molecules

Colloids have a rich history of being used as 'big atoms' mimicking real atoms to study crystallization, gelation and the glass transition of condensed matter. Emulating the dynamics of molecules, however, has remained elusive. Recent advances in colloid chemistry allow patchy particles to be synthesized with accurate control over shape, functionality and coordination number. Here, we show that colloidal alkanes, specifically colloidal cyclopentane, assembled from tetrameric patchy particles by critical Casimir forces undergo the same chemical transformations as their atomic counterparts, allowing their dynamics to be studied in real time. We directly observe transitions between chair and twist conformations in colloidal cyclopentane, and we elucidate the interplay of bond bending strain and entropy in the molecular transition states and ring-opening reactions. These results open the door to investigate complex molecular kinetics and molecular reactions in the high-temperature classical limit, in which the colloidal analogue becomes a good model.

Mechanisms of Local Stress Amplification in Axons near the Gray-White Matter Interface

Diffuse axonal injury is a primary neuropathological feature of concussion and is thought to greatly contribute to the classical symptoms of decreased processing speed and memory dysfunction. Although previous studies have investigated the injury biomechanics at the micro- and mesoscale of concussion, few have addressed the multiscale transmission of mechanical loading at thresholds that can induce diffuse axonal injury. Because it has been recognized that axonal pathology is commonly found at anatomic interfaces across all severities of traumatic brain injury, we combined computational, analytical, and experimental approaches to investigate the potential mechanical vulnerability of axons that span the gray-white tissue interface. Our computational models predict that material heterogeneities at the gray-white interface lead to a highly nonuniform distribution of stress in axons, which was most amplified in axonal regions near the interface. This mechanism was confirmed using an analytical model of an individual fiber in a strained bimaterial interface. Comparisons of these collective data with histopathological evaluation of a swine model of concussion demonstrated a notably similar pattern of axonal damage adjacent to the gray-white interface. The results suggest that the tissue property mismatch at the gray-white matter interface places axons crossing this region at greater risk of mechanical damage during brain tissue deformation from traumatic brain injury.

Vascular Extracellular Matrix Remodeling and Hypertension

Significance: The vascular extracellular matrix (ECM) not only provides mechanical stability but also manipulates vascular cell behaviors, which are crucial for vascular function and homeostasis. ECM remodeling, which alters vascular wall mechanical properties and exposes vascular cells to bioactive molecules, is involved in the development and progression of hypertension. Recent Advances: This brief review summarized the dynamic changes in ECM components and their modification and degradation during hypertension and after antihypertensive treatment. We also discussed how alterations in the ECM amount, assembly, mechanical properties, and degradation fragment generation provide input into the pathological process of hypertension. Critical Issues: Although the relevance between ECM remodeling and hypertension has been recognized, the underlying mechanism by which ECM remodeling initiates the development of hypertension remains unclear. Therefore, the modulation of ECM remodeling on arterial stiffness and hypertension in genetically modified rodent models is summarized in this review. The circulating biomarkers based on ECM metabolism and therapeutic strategies targeting ECM disorders in hypertension are also introduced. Future Directions: Further research will provide more comprehensive understanding of ECM remodeling in hypertension by the application of matridomic and degradomic approaches. The better understanding of mechanisms underlying vascular ECM remodeling may provide novel potential therapeutic strategies for preventing and treating hypertension. Antioxid. Redox Signal. 34, 765-783.

Recursive feedback between matrix dissipation and chemo-mechanical signaling drives oscillatory growth of cancer cell invadopodia

Most extracellular matrices (ECMs) are known to be dissipative, exhibiting viscoelastic and often plastic behaviors. However, the influence of dissipation, in particular mechanical plasticity in 3D confining microenvironments, on cell motility is not clear. In this study, we develop a chemo-mechanical model for dynamics of invadopodia, the protrusive structures that cancer cells use to facilitate invasion, by considering myosin recruitment, actin polymerization, matrix deformation, and mechano-sensitive signaling pathways. We demonstrate that matrix dissipation facilitates invadopodia growth by softening ECMs over repeated cycles, during which plastic deformation accumulates via cyclic ratcheting. Our model reveals that distinct protrusion patterns, oscillatory or monotonic, emerge from the interplay of timescales for polymerization-associated extension and myosin recruitment dynamics. Our model predicts the changes in invadopodia dynamics upon inhibition of myosin, adhesions, and the Rho-Rho-associated kinase (ROCK) pathway. Altogether, our work highlights the role of matrix plasticity in invadopodia dynamics and can help design dissipative biomaterials to modulate cancer cell motility.

Diagnostic magnetic resonance imaging in synovial chondromatosis of the temporomandibular joint

The aim of this paper was to investigate the clinical and magnetic resonance imaging (MRI) features of synovial chondromatosis (SC) of the temporomandibular joint (TMJ). Fourteen patients with SC of the TMJ were included in the study. Clinical and MRI features were analysed and divided into three types based on MRI classification: type I with loose bodies, type II with homogeneous masses, and type III with a mixture of loose bodies and homogeneous masses. All SCs occurred in the superior compartment of the TMJ. There were two patients (14%) categorised as type I, five (36%) as type II and seven (50%) as type III. Four patients (29%) had disc perforation, and nine had bone erosion; among those nine, seven (78%) had type III and two (22%) type II. Histological examination showed inflammation and calcification in the synovial membrane and, and cartilage of the hyaline type in all cases. MRI has advantages in the diagnosis of SC.

Triplex qRT-PCR with specific probe for synchronously detecting Bovine parvovirus, bovine coronavirus, bovine parainfluenza virus and its applications

Bovine parvovirus (BPV), bovine coronavirus (BCoV) and bovine parainfluenza virus (BPIV) are common etiologies causing gastrointestinal and respiratory diseases in dairy herds. However, there are few reports on the synchronous detection of BPV, BCoV and BPIV. The present article aimed to develop a quick and accurate RT-PCR assay to synchronously detect BPV, BCoV and BPIV based on their specific probes. One pair universal primers, one pair specific primers and one specific probe was designed and synthesized. After the concentrations of primer and probe and annealing temperature were strictly optimized, the specificity, sensitivity and repeatability of the established triplex probe qRT-PCR were evaluated, respectively. The results showed the recombinant plasmids of pMD18-T-BPV, pMD18-T-BCoV and pMD18-T-BPIV were 554bp, 699bp and 704bp, respectively. The optimal annealing temperature was set at 45.0°C for triplex qRT-PCR. The triplex probe qRT-PCR can only synchronously detect BPV, BCoV and BPIV. Detection sensitivities were 2.0×102, 2.0×102 and 2.0×101 copies/μL for BPV, BCoV and BPIV, being 1000-fold greater than that in the conventional PCR. Detection of clinical samples demonstrated that triplex probe qRT-PCR had a higher sensitivity and specificity. The intra-assay and inter-assay coefficient of variation were lower than 2.0%. Clinical specimens verified that the triplex qRT-PCR had a higher sensitivity and specificity than universal PCR. In conclusion, this triplex probe qRT-PCR could detect only BPV, BCoV and BPIV. Minimum detection limits were 2.0×102 copies/μL for BPV and BCoV, and 2.0×101 copies/μL for BPIV. The sensitivity of this triplex probe qRT-PCR was 1000-fold greater than that in the conventional PCR. The newly qRT-PCR could be used to monitor or differentially diagnose virus infection.

Direct laser acceleration of electrons assisted by strong laser-driven azimuthal plasma magnetic fields

A high-intensity laser beam propagating through a dense plasma drives a strong current that robustly sustains a strong quasistatic azimuthal magnetic field. The laser field efficiently accelerates electrons in such a field that confines the transverse motion and deflects the electrons in the forward direction. Its advantage is a threshold rather than resonant behavior, accelerating electrons to high energies for sufficiently strong laser-driven currents. We study the electron dynamics via a test-electron model, specifically deriving the corresponding critical current density. We confirm the model's predictions by numerical simulations, indicating energy gains two orders of magnitude higher than achievable without the magnetic field.

Energy gain by laser-accelerated electrons in a strong magnetic field

This paper deals with electron acceleration by a laser pulse in a plasma with a static uniform magnetic field B_{*}. The laser pulse propagates perpendicular to the magnetic field lines with the polarization chosen such that (E_{laser}·B_{*})=0. The focus of the work is on the electrons with an appreciable initial transverse momentum that are unable to gain significant energy from the laser in the absence of the magnetic field due to strong dephasing. It is shown that the magnetic field can initiate an energy increase by rotating such an electron, so that its momentum becomes directed forward. The energy gain continues well beyond this turning point where the dephasing drops to a very small value. In contrast to the case of purely vacuum acceleration, the electron experiences a rapid energy increases with the analytically derived maximum energy gain dependent on the strength of the magnetic field and the phase velocity of the wave. The energy enhancement by the magnetic field can be useful at high laser amplitudes, a_{0}≫1, where the acceleration similar to that in the vacuum is unable to produce energetic electrons over just tens of microns. A strong magnetic field helps leverage an increase in a_{0} without a significant increase in the interaction length.

Correction: Opposite responses of normal hepatocytes and hepatocellular carcinoma cells to substrate viscoelasticity

Correction for 'Opposite responses of normal hepatocytes and hepatocellular carcinoma cells to substrate viscoelasticity' by Kalpana Mandal et al., Biomater. Sci., 2020, 8, 1316-1328.

Fundamental Characteristics of Neuron Adhesion Revealed by Forced Peeling and Time-Dependent Healing

A current bottleneck in the advance of neurophysics is the lack of reliable methods to quantitatively measure the interactions between neural cells and their microenvironment. Here, we present an experimental technique to probe the fundamental characteristics of neuron adhesion through repeated peeling of well-developed neurite branches on a substrate with an atomic force microscopy cantilever. At the same time, a total internal reflection fluorescence microscope is also used to monitor the activities of neural cell adhesion molecules (NCAMs) during detaching. It was found that NCAMs aggregate into clusters at the neurite-substrate interface, resulting in strong local attachment with an adhesion energy of ∼0.1 mJ/m² and sudden force jumps in the recorded force-displacement curve. Furthermore, by introducing a healing period between two forced peelings, we showed that stable neurite-substrate attachment can be re-established in 2-5 min. These findings are rationalized by a stochastic model, accounting for the breakage and rebinding of NCAM-based molecular bonds along the interface, and provide new insights into the mechanics of neuron adhesion as well as many related biological processes including axon outgrowth and nerve regeneration.

Opposite responses of normal hepatocytes and hepatocellular carcinoma cells to substrate viscoelasticity

The cellular microenvironment plays a critical role in cell differentiation, proliferation, migration, and homeostasis. Recent studies have shown the importance of substrate viscosity in determining cellular function. Here, we study the mechanoresponse of normal hepatocytes and hepatocellular carcinoma cells (HCC) to elastic and viscoelastic substrates using the Huh7 cell line derived from a human liver tumor and primary human hepatocytes (PHH). Unlike PHH and fibroblasts, which respond to viscoelastic substrates by reducing spreading area and actin bundle assembly compared to purely elastic substrates of the same stiffness, Huh7 cells spread faster on viscoelastic substrates than on purely elastic substrates. The steady state spreading areas of Huh7 cells are larger on viscoelastic substrates, whereas the opposite effect occurs with PHH cells. The viscoelasticity of the microenvironment also promotes motility and multiple long protrusions in Huh7 cells. Pharmacologic disruption of the actin assembly makes cells unable to spread on either elastic or viscoelastic substrates. In contrast, upon vimentin perturbation, cells still spread to a limited degree on elastic substrates but are unable to spread on viscoelastic substrates. The time evolution of cell traction force shows that the peak occurs at an earlier time point on viscoelastic substrates compared to elastic substrates. However, the total force generation at steady state is the same on both substrates after 4 hours. Our data suggest that stress relaxation time scales of the viscoelastic substrate regulate cell dynamics and traction force generation, indicating different binding-unbinding rates of the proteins that form cell attachment sites in HCC cells and normal hepatocytes. These results suggest that liver cancer cells may have different characteristic lifetimes of binding to the substrate in comparision to normal cells, which might cause differences in cell spreading and motility within the diseased tissue.

Physiological response of Secale cereale L. seedlings under freezing-thawing and alkaline salt stress

Freezing-thawing and saline-alkaline are the major abiotic stress for the pasture in most high-latitude areas, which are serious threats to the yield of pasture. In this study, the osmotic adjustment substances, membrane lipid peroxidation, and antioxidant enzymes activities of rye (Secale cereale L., cv. Dongmu-70) seedlings under different treatments: CK (no treatment), SC (Na₂CO₃ treatment), FT (freezing-thawing treatment), and FT+SC (combined Na₂CO₃ and freezing-thawing treatments), were investigated. At the freezing stage, the content of MDA and proline, the activity of APX, SOD, and POD increased with the decrease of the temperature in the leaves of rye seedlings in FT and FT+SC treatments and reached the maximum value at - 5 °C. In addition, the content of protein and H₂O₂, CAT activity reached the maximum value at 0 °C; the damage is larger under low temperature stress at 0 °C and - 5 °C in rye seedling. At the thawing stage, the content of MDA and H₂O₂ in seedling leaves decreased in FT and FT + SC treatments. These results demonstrated that proline content and antioxidant enzymes activities could play an important role in protecting cytomembrane and scavenging ROS respectively in rye under alkaline salt stress and freezing-thawing stress. The result also indicated rye seedlings were subjected to a freezing-thawing stress which resulted in a reversible (recoverable) injury.

TaqMan real-time PCR for detecting bovine viral diarrhea virus

The present study was aimed to establish a novel TaqMan real-time PCR (RTm-PCR) for detecting and typing bovine viral diarrhea virus (BVDV), and also to develop a diagnostic protocol which simplifies sample collection and processing. Universal primers and TaqMan-MGB probes were designed from the known sequences of conserved 5' - and 3'-untranslated regions (5'UTR, 3'UTR) of the NADL strain of BVDV. Prior to optimizing the assay, cDNAs were transcribed in vitro to make standard curves. The sensitivity, specificity and stability (reproducibility) were evaluated. The RTm-PCR was tested on the 312 feces specimens collected from persistently infected (PI) calves. The results showed the optimum conditions for RTm-PCR were 17.0 μmol/L primer, 7.5 μmol/L probe and 51.4°C annealing temperature. The established TaqMan RTm-PCR assay could specially detect BVDV without detecting any other viruses. Its detection limit was 1.55×100 copies/μL for viral RNA. It was 10000-fold higher than conventional PCR with excellent specificity and reproducibility. 312 samples were tested using this method and universal PCR from six dairy farms, respectively. Positive detections were found in 49 and 44 feces samples, respectively. The occurrence rate was 89.80%. In conclusion, the established TaqMan RTm-PCR could rapidly detect BVDV and effectively identify PI cattle. The detection limit of RTm-PCR was 1.55 copies/μL. It will be beneficial for enhancing diagnosis and therapy efficacy and reduce losses in cattle farms.

Deflection of a reflected intense circularly polarized light beam induced by asymmetric radiation pressure

A deflection effect of an intense laser beam with spin angular momentum is revealed theoretically by an analytical modeling using radiation pressure and momentum balance of laser plasma interaction in the relativistic regime as a deviation from the law of reflection. The reflected beam deflects out of the plane of incidence with a deflection angle up to several milliradians, when a nonlinear polarized laser, with the intensity I_{0}∼10^{19}W/cm^{2} and duration around tens of femtoseconds, is obliquely incident and reflected by an overdense plasma target. This effect originates from the asymmetric radiation pressure caused by spin angular momentum of the laser photons. The dependence of the deflection angle of a Gaussian-type laser on the parameters of laser pulse and plasma foil is theoretically derived, which is also confirmed by three-dimensional particle-in-cell simulations of circularly polarized laser beams with the different intensity and pulse duration.

Radiation reaction as an energy enhancement mechanism for laser-irradiated electrons in a strong plasma magnetic field

Conventionally, friction is understood as a mechanism depleting a physical system of energy and as an unavoidable feature of any realistic device involving moving parts. In this work, we demonstrate that this intuitive picture loses validity in nonlinear quantum electrodynamics, exemplified in a scenario where spatially random friction counter-intuitively results in a highly directional energy flow. This peculiar behavior is caused by radiation friction, i.e., the energy loss of an accelerated charge due to the emission of radiation. We demonstrate analytically and numerically how radiation friction can dramatically enhance the energy gain by electrons from a laser pulse in a strong magnetic field that naturally arises in dense laser-irradiated plasma. We find the directional energy boost to be due to the transverse electron momentum being reduced through friction whence the driving laser can accelerate the electron more efficiently. In the considered example, the energy of the laser-accelerated electrons is enhanced by orders of magnitude, which then leads to highly directional emission of gamma-rays induced by the plasma magnetic field.