Natural Image Reconstruction from fMRI Based on Node-Edge Interaction and Multi-Scale Constraint.

Reconstructing natural stimulus images using functional magnetic resonance imaging (fMRI) is one of the most challenging problems in brain decoding and is also the crucial component of a brain-computer interface. Previous methods cannot fully exploit the information about interactions among brain regions. In this paper, we propose a natural image reconstruction method based on node-edge interaction and a multi-scale constraint. Inspired by the extensive information interactions in the brain, a novel graph neural network block with node-edge interaction (NEI-GNN block) is presented, which can adequately model the information exchange between brain areas via alternatively updating the nodes and edges. Additionally, to enhance the quality of reconstructed images in terms of both global structure and local detail, we employ a multi-stage reconstruction network that restricts the reconstructed images in a coarse-to-fine manner across multiple scales. Qualitative experiments on the generic object decoding (GOD) dataset demonstrate that the reconstructed images contain accurate structural information and rich texture details. Furthermore, the proposed method surpasses the existing state-of-the-art methods in terms of accuracy in the commonly used n-way evaluation. Our approach achieves 82.00%, 59.40%, 45.20% in n-way mean squared error (MSE) evaluation and 83.50%, 61.80%, 46.00% in n-way structural similarity index measure (SSIM) evaluation, respectively. Our experiments reveal the importance of information interaction among brain areas and also demonstrate the potential for developing visual-decoding brain-computer interfaces.

Contribution of pudendal nerve injury to stress urinary incontinence in a male rat model.

Urinary incontinence is a common complication following radical prostatectomy, as the surgery disturbs critical anatomical structures. This study explored how pudendal nerve (PN) injury affects urinary continence in male rats. In an acute study, leak point pressure (LPP) and external urethral sphincter electromyography (EMG) were performed on six male rats with an intact urethra, the urethra exposed (UE), the PN exposed (NE), and after PN transection (PNT). In a chronic study, LPP and EMG were tested in 67 rats 4 days, 3 weeks, or 6 weeks after sham PN injury, PN crush (PNC), or PNT. Urethras were assessed histologically. Acute PNT caused a significant decrease in LPP and EMG amplitude and firing rate compared to other groups. PNC resulted in a significant reduction in LPP and EMG firing rate 4 days, 3 weeks, and 6 weeks later. EMG amplitude was also significantly reduced 4 days and 6 weeks after PNC. Neuromuscular junctions were less organized and less innervated after PNC or PNT at all timepoints compared to sham injured animals. Collagen infiltration was significantly increased after PNC and PNT compared to sham at all timepoints. This rat model could facilitate preclinical testing of neuroregenerative therapies for post-prostatectomy incontinence.

Alkbh5 plays indispensable roles in maintaining self-renewal of hematopoietic stem cells.

Alkbh5 is one of the primary demethylases responsible for reversing N6-methyladenosine (m6A) modifications on mRNAs, and it plays a crucial role in many physiological and pathological processes. Previous studies have shown that Alkbh5 is required for maintaining the function of leukemia stem cells but is dispensable for normal hematopoiesis. In this study, we found that Alkbh5 deletion led to a moderate increase in the number of multiple progenitor cell populations while compromising the long-term self-renewal capacity of hematopoietic stem cells (HSCs). Here, we used RNA-seq and m6A-seq strategies to explore the underlying molecular mechanism. At the molecular level, Alkbh5 may regulate hematopoiesis by reducing m6A modification of Cebpa and maintaining gene expression levels. Overall, our study unveiled an essential role for Alkbh5 in regulating HSC homeostasis and provides a reference for future research in this area.

Status and correlates of children's exposure to secondhand smoke at home: A survey in Chongqing, China.

INTRODUCTION: The home is the primary source of children's exposure to secondhand smoke. This study investigated the status and influencing factors of child exposure to secondhand smoke at home when people smoke in the household. METHODS: Participants with at least one child living in their household from 10 communities in Chongqing were recruited and provided a self-administered questionnaire using a multistage proportional random sampling design from June to August 2021. The chi-squared test and binary logistic regression analyses were used to identify influencing factors. RESULTS: The questionnaire completed by 1345 families showed that 631 (46.9%) families lived with smokers in their household, and 509 (80.7%) of those families reported that smoking occurred within the home while the children were present. Binary logistic regression analyses demonstrated that the time between waking up and household smokers having the first cigarette of the day (OR=0.44; 95% CI: 0.22-0.85), changes to smoking habits and behaviors within the last six months (OR=1.76; 95% CI: 1.06-2.90), attitudes towards tobacco control in the household (OR=2.91; 95% CI: 1.72-4.92), self-efficacy in maintaining a smoke-free home (OR=2.27; 95% CI: 1.36-3.79), having rules to maintain a smoke-free home (OR=3.25; 95% CI: 1.68-6.29), and the status of providing cigarettes to guests at home (OR=11.0; 95% CI: 1.33-90.8) were associated with exposure to SHS. CONCLUSIONS: Education focusing on the impact of smoking on children's health should be encouraged. Smoke-free homes should be established, and smoking restrictions in the household should be enacted. Therefore, information about the available tobacco-control services should be given to family members and be used properly. It is an effective way to decrease the risk of at-home exposure to SHS for children, to overcome any obstacles in tobacco control.

Brain-Derived Neurotrophic Factor Is Indispensable to Continence Recovery after a Dual Nerve and Muscle Childbirth Injury Model.

In women, stress urinary incontinence (SUI), leakage of urine from increased abdominal pressure, is correlated with pudendal nerve (PN) injury during childbirth. Expression of brain-derived neurotrophic factor (BDNF) is dysregulated in a dual nerve and muscle injury model of childbirth. We aimed to use tyrosine kinase B (TrkB), the receptor of BDNF, to bind free BDNF and inhibit spontaneous regeneration in a rat model of SUI. We hypothesized that BDNF is essential for functional recovery from the dual nerve and muscle injuries that can lead to SUI. Female Sprague-Dawley rats underwent PN crush (PNC) and vaginal distension (VD) and were implanted with osmotic pumps containing saline (Injury) or TrkB (Injury + TrkB). Sham Injury rats received sham PNC + VD. Six weeks after injury, animals underwent leak-point-pressure (LPP) testing with simultaneous external urethral sphincter (EUS) electromyography recording. The urethra was dissected for histology and immunofluorescence. LPP after injury and TrkB was significantly decreased compared to Injury rats. TrkB treatment inhibited reinnervation of neuromuscular junctions in the EUS and promoted atrophy of the EUS. These results demonstrate that BDNF is essential to neuroregeneration and reinnervation of the EUS. Treatments aimed at increasing BDNF periurethrally could promote neuroregeneration to treat SUI.

The Anima as an Archetype of Human Resilience in the Face of Calamity.

This paper will provide a theoretical basis for looking at a dream in the analysis of a client during a calamity. Finding the archetype of the anima is a way of responding to a crisis, in this case to the COVID-19 pandemic period. With all the basic instincts disrupted by a catastrophe, the emergence of the anima, as archetype of life, is there to remind us how to survive and recover. The anima archetype, often representing psychological resilience in ancient myths, shows up in dreams to guide human transformation from the struggle to survive trauma to the art of living a full life.

Cet article fournira un fondement théorique pour l'exploration d'un rêve dans l'analyse d'un client durant un désastre. Trouver l'archétype de l'anima est une manière de répondre à une crise, ici à la période de pandémie. Lorsque que tous les instincts fondamentaux sont perturbés par la catastrophe, l'émergence de l'anima en tant qu'archétype de la vie vient nous rappeler comment survivre et se remettre. L'archétype de l'anima, qui représente souvent la résilience psychologique dans les mythes anciens, apparait dans les rêves pour guider la transformation humaine dans la lutte pour survivre au traumatisme et pour aller vers l'art de vivre une vie pleine.

Este artículo ofrece una base teórica para observar un sueño en el análisis de un cliente durante una calamidad. Encontrar el arquetipo del ánima es una forma de responder a una crisis, en este caso al periodo pandémico. Con todos los instintos básicos perturbados por una catástrofe, la aparición del ánima como arquetipo de la vida está ahí para recordarnos cómo sobrevivir y recuperarnos. El arquetipo del ánima, que a menudo representa la resiliencia psicológica en los mitos antiguos, aparece en los sueños para guiar la transformación humana en la lucha por sobrevivir al trauma hacia el arte de vivir una vida plena.

Brain-Derived Neurotrophic Factor Is an Important Therapeutic Factor in Mesenchymal Stem Cell Secretions for Treatment of Traumatic Peripheral Pelvic Injuries.

Traumatic neuromuscular injury to the pudendal nerve and urethra during childbirth does not regenerate well and contributes to stress urinary incontinence in women. Mesenchymal stem cells (MSCs) can improve neuroregeneration via their secretions, or secretome, which includes brain-derived neurotrophic factor (BDNF). In this study, we investigated whether BDNF is a key factor in the secretome of MSCs for the facilitation of functional recovery following a dual simulated childbirth injury. BDNF knockdown (KD) MSCs were created using an anti-BDNF shRNA lentivirus vector. A scrambled sequence was used as a transduction control (scrambled). Cells were cultured for 24 h before media was concentrated 50x to create concentrated conditioned media (CCM) containing MSC secretome. CCM of unmanipulated MSCs was screened for high BDNF expression (high BDNF CCM). Concentrated control media (CM) was created by concentrating media not conditioned by cells. Female Sprague-Dawley rats underwent bilateral pudendal nerve crush and vaginal distension (Injury) or sham injury. One hour and 1 week after injury, sham injured rats received CM, and injured rats received CM, high BDNF CCM, KD CCM, or scrambled CCM (300 µl intraperitoneally). Three weeks after injury, rats underwent leak point pressure (LPP) and pudendal nerve sensory branch potential (PNSBP) recordings. The urethra and pudendal nerve were harvested for anatomical assessment. ANOVA followed by the Student-Newman-Keuls test determined significant differences between groups (p < 0.05). BDNF KD CCM had significantly decreased BDNF concentration compared to scrambled CCM, while the concentration in high BDNF CCM was significantly increased. LPP was significantly decreased in CM and KD CCM treated animals compared to sham injury, but not with scrambled or high BDNF CCM. PNSBP firing rate showed a significant decrease with CM treatment compared to sham injury. Neuromuscular junctions in the urethral sphincter in KD CCM, scrambled CCM, and high BDNF CCM were healthier than CM treated rats. While anatomical and nerve function tests demonstrate regeneration of the pudendal nerve with any CCM treatment, LPP results suggest it takes longer to recover continence with reduced BDNF in CCM. BDNF in MSC CCM is an important factor for the acceleration of recovery from a dual nerve and muscle injury.

Status and correlates of home smoking bans after the implementation of the smoke-free legislation in public places: A survey in Chongqing.

INTRODUCTION: Secondhand smoke exposure in many countries decreased dramatically after the implementation of smoke-free legislation in public places, but the exposure at home did not change to the same degree. The aim of this study was to describe the status and correlates of a home smoking ban in Chongqing, China. METHODS: From June to August 2021, we selected two healthcare centers in the East, West, North, South and Middle regions of Chongqing. We investigated the family smoke-free situation in the selected region using a stratified random sampling method. A chi-squared test was performed to compare the totally and partially smoke-free homes, and a binary logistic regression model was used to analyze the correlates of smoke-free rules at home. RESULTS: The study investigated 2121 families, among which 884 (41.7%) implemented a total ban on smoking at home. The covariates included age (OR=1.54; 95% CI: 1.18-2.01), living with children aged <14 years (OR=1.51; 95% CI: 1.20-1.90), no smokers in the family (OR=2.37; 95% CI: 1.78-3.17), awareness of the hazards of secondhand smoke (OR=1.30; 95% CI: 1.07-1.59), worrying about the impact of smoking in the presence of children on health (OR=1.92; 95% CI: 1.25-2.95), no difficulty (OR=1.34; 95% CI: 1.07-1.67) and confidence (OR=1.73; 95% CI: 1.41-2.13) in stopping others from smoking, no smoking rules in cars (OR=3.67; 95% CI: 2.58-5.22), and frequency of entertaining guests with cigarettes (OR=0.41; 95% CI: 0.28-0.59). CONCLUSIONS: It is common for households in Chongqing to have smoking bans, especially those with children. If a family has members that are smokers, education researchers should pay more attention to the hazards of secondhand smoke on the health of family members, and to adopt more tobacco control measures and enhance the self-efficacy of implementing a home smoking ban. Helping smokers to quit is a vital way to decrease the hazards of cigarettes.

Insufficiency of FZR1 disturbs HSC quiescence by inhibiting ubiquitin-dependent degradation of RUNX1 in aplastic anemia.

FZR1 has been implicated as a master regulator of the cell cycle and quiescence, but its roles and molecular mechanisms in the pathogenesis of severe aplastic anemia (SAA) are unclear. Here, we report that FZR1 is downregulated in SAA HSCs compared with healthy control and is associated with decreased quiescence of HSC. Haploinsufficiency of Fzr1 shows impaired quiescence and self-renewal ability of HSC in two Fzr1 heterozygous knockout mouse models. Mechanistically, FZR1 insufficiency inhibits the ubiquitination of RUNX1 protein at lysine 125, leading to the accumulation of RUNX1 protein, which disturbs the quiescence of HSCs in SAA patients. Moreover, downregulation of Runx1 reversed the loss of quiescence and impaired long-term self-renew ability in Fzr1+/- HSCs in vivo and impaired repopulation capacity in BM from SAA patients in vitro. Our findings, therefore, raise the possibility of a decisive role of the FZR1-RUNX1 pathway in the pathogenesis of SAA via deregulation of HSC quiescence.

Brain derived neurotrophic factor mediates accelerated recovery of regenerative electrical stimulation in an animal model of stress urinary incontinence.

OBJECTIVE: Stress urinary incontinence (SUI) is prevalent among older women and can result from insufficient regeneration of the pudendal nerve (PN). Electrical stimulation (ES) of the PN upregulates brain derived neurotrophic factor (BDNF) and accelerates regeneration. Using tyrosine kinase B (TrkB) to reduce the availability of free BDNF, the aim of this study was to determine if BDNF is necessary for accelerated recovery via ES in a model of SUI. METHODS: Our SUI model consists of Female Sprague-Dawley rats, whose PNs were crushed bilaterally twice for 30 s, followed by insertion of a modified Foley catheter into the vagina with balloon inflation for 4 h. These rats were divided into 4 groups: 1) Sham PN crush and sham vaginal distension without electrode implantation and with saline treatment (sham injury); 2) SUI with sham stimulation and saline treatment (SUI); 3) SUI and ES with saline treatment (SUI&ES); and 4) SUI and ES with TrkB treatment (SUI&ES&TrkB). Animals underwent ES or sham stimulation four times a week for two weeks. Four weeks after injury, animals underwent functional testing consisting of leak point pressure (LPP) with simultaneous external urethral sphincter (EUS) electromyography (EMG) and pudendal nerve recordings. Data was analyzed using ANOVA with Holm-Sidak posthoc test (p < 0.05). EUS and PN specimen were sectioned and stained to semi-quantitatively evaluate morphology, regeneration, and reinnervation. RESULTS: LPP and EUS EMG firing rate were significantly increased in the sham injury and SUI&ES groups compared to the SUI and SUI&ES&TrkB groups. EUS of SUI rats showed few innervated neuromuscular junctions compared to sham injured rats, while both treatment groups showed an increase in reinnervated neuromuscular junctions. CONCLUSION: ES accelerates functional recovery via a BDNF-mediated pathway in a model of SUI. These findings suggest ES could be used as a potential regenerative therapy for women with SUI.

Quantitative Morphometry of Elastic Fibers in Pelvic Organ Prolapse.

Pelvic organ prolapse (POP) is common among older women who have delivered children vaginally. While the pathophysiology is not fully delineated, POP can occur in part from insufficient repair of disrupted elastic matrix fibers. Quantification of structural changes to elastic fibers has not been described previously for POP. The goal of this paper is to present a validated technique for morphometric analysis of elastic fibers in vaginal tissue cultures from lysyl oxidase like-1 knock out (LOXL1 KO) mice with POP. The effect of LOXL1 KO, effect of POP, effect of culture, and effect of elastogenic treatment on the changes in elastin fiber characteristics were tested using vaginal tissues from wild type multiparous (WT), LOXL1 KO multiparous prolapsed (POP) and LOXL1 KO multiparous non-prolapsed (NP) mice. Our results show significantly higher mean aspect ratio, maximum diameter and perimeter length in POP compared to NP after 3 weeks of tissue culture. Further, treatment of POP tissues in culture with growth factors with previously documented elastogenic effects caused a significant increase in the mean area and perimeter length of elastic fibers. This technique thus appears to be useful in quantifying structural changes and can be used to assess the pathophysiology of POP and the effect of elastogenic treatments with potential for POP.

Nuclear DEK preserves hematopoietic stem cells potential via NCoR1/HDAC3-Akt1/2-mTOR axis.

The oncogene DEK is found fused with the NUP214 gene creating oncoprotein DEK-NUP214 that induces acute myeloid leukemia (AML) in patients, and secreted DEK protein functions as a hematopoietic cytokine to regulate hematopoiesis; however, the intrinsic role of nuclear DEK in hematopoietic stem cells (HSCs) remains largely unknown. Here, we show that HSCs lacking DEK display defects in long-term self-renew capacity, eventually resulting in impaired hematopoiesis. DEK deficiency reduces quiescence and accelerates mitochondrial metabolism in HSCs, in part, dependent upon activating mTOR signaling. At the molecular level, DEK recruits the corepressor NCoR1 to repress acetylation of histone 3 at lysine 27 (H3K27ac) and restricts the chromatin accessibility of HSCs, governing the expression of quiescence-associated genes (e.g., Akt1/2, Ccnb2, and p21). Inhibition of mTOR activity largely restores the maintenance and potential of Dek-cKO HSCs. These findings highlight the crucial role of nuclear DEK in preserving HSC potential, uncovering a new link between chromatin remodelers and HSC homeostasis, and have clinical implications.

Zfp521 is essential for the quiescence and maintenance of adult hematopoietic stem cells under stress.

Zinc finger protein 521 (Zfp521), a quiescent hematopoietic stem cell (HSC)-enriched transcription factor, is involved in the self-renewal and differentiation of fetal liver HSC. However, its role in adult hematopoiesis remains elusive. Here, we found that Zfp521 deletion did not inhibit adult hematopoiesis under homeostatic conditions. In contrast, Zfp521-null chimeric mice showed significantly reduced pool size of HSC and hematopoietic progenitor cells associated with increased apoptosis and loss of quiescence. Competitive serial transplantation assays revealed that Zfp521 regulates HSC self-renewal and differentiation under regenerative stress. Mechanistically, Zfp521 transcriptionally repressed Rela expression by increasing H3K9ac and decreasing H3K9me3 levels in its promoter. Knockdown of Rela inhibited the hyper-activated NF-κB pathway and reversed the loss of quiescence in Zfp521-null HSC under stress. Thus, our results reveal a previously unrecognized role for Zfp521 as critical regulator of quiescence and self-renewal of HSC in adult hematopoiesis mediated at least partly by controlling Rela expression.

Artesunate interrupts the self-transcriptional activation of MarA to inhibit RND family pumps of Escherichia coli.

Resistance-Nodulation-Division (RND) family pumps are responsible for producing multidrug resistance in Escherichia coli; however, there has been little study of targeted inhibitors of RNDs. In the present study, we investigated the inhibition of RND pumps by artesunate (AS) in E. coli, and further investigated the mechanism with respect to MarA, a regulator of RNDs. Although AS had no direct antibacterial effect, it showed a synergistic effect in combination with ß-lactams against E. coli ATCC35218 in vitro and in vivo, suggesting it possesses antibacterial enhancement activity. Notably, AS, alone or in combination with ß-lactams, downregulated the mRNA expression levels of marA, soxS, and rob, known as the marA-soxS-rob regulon, which then decreased the expression levels of RNDs, thereby increased ampicillin accumulation within ATCC35218. Using gene-deletion strains, we found that the antibacterial sensitization effect of AS persisted in wildtype bacteria, but was completely lost in the strain lacking marA, and decreased in the strain lacking soxS or rob, suggesting marA plays a crucial role in the sensitization of AS. Critically, we showed that AS inhibited the binding of MarA to the promoter of marA itself, not acrB, resulting in decreased mRNA expression of both acrB and marA. Mechanistically, we found AS directly bound to the central cavity of MarA through the R59 and K62 residues, and thus altered the charge distribution of MarA to interrupt the recognition between MarA and its promoter. We concluded that AS interrupts the self-transcriptional activation of MarA, thereby inhibits MarA-dependent mRNA expression of marA, acrAB, and tolC, and also certain other RNDs and regulatory genes related to MarA. Therefore, AS is a novel inhibitor of RND pumps that acts on the regulator MarA.

The pudendal nerve motor branch regenerates via a brain derived neurotrophic factor mediated mechanism.

Peripheral nerve injuries can significantly reduce quality of life. While some recover, most do not recover fully, resulting in neuropathic pain and loss of sensation and motor function. Research on the mechanisms of peripheral nerve regeneration could elucidate poor patient outcomes and potential treatments. This study was designed to determine if brain derived neurotrophic factor (BDNF) is necessary for pudendal nerve regeneration and functional recovery. Peripheral administration of tyrosine kinase B functional chimera (TrkB) was used to inhibit the BDNF regenerative pathway. Female Sprague-Dawley rats received tyrosine kinase B functional chimera (TrkB) or saline after a pudendal nerve crush (PNC) or Sham PNC and were divided into three groups: Sham PNC, PNC + Saline, and PNC + TrkB. Seven days after injury, relative ßII tubulin expression (1.0 ± 0.2) was significantly decreased after PNC + TrkB compared to PNC + saline (2.9 ± 1.0). Three weeks after injury, BDNF plasma concentration (1320.8 ± 278.1 pg/ml) was significantly reduced in PNC + TrkB compared to PNC + saline rats (2053.4 ± 211.0 pg/ml). Pudendal nerve motor branch firing rate (54.0 ± 9.5 Hz) was significantly decreased in the PNC + TrkB group compared to the PNC + saline group (120.4 ± 17.1 Hz); while nerve firing rate of the PNC + saline group was not significantly different from sham PNC rats (121.8 ± 26.6 Hz). This study demonstrated that peripheral administration of TrkB bound free BDNF and inhibited the regenerative response after PNC. BDNF is necessary for normal PN motor branch recovery after PNC.

Therapeutic potential of muscle growth promoters in a stress urinary incontinence model.

Weakness of urinary sphincter and pelvic floor muscles can cause insufficient urethral closure and lead to stress urinary incontinence. Bimagrumab is a novel myostatin inhibitor that blocks activin type II receptors, inducing skeletal muscle hypertrophy and attenuating muscle weakness. ß2-Adrenergic agonists, such as 5-hydroxybenzothiazolone derivative (5-HOB) and clenbuterol, can enhance muscle growth. We hypothesized that promoting muscle growth would increase leak point pressure (LPP) by facilitating muscle recovery in a dual-injury (DI) stress urinary incontinence model. Rats underwent pudendal nerve crush (PNC) followed by vaginal distension (VD). One week after injury, each rat began subcutaneous (0.3 mL/rat) treatment daily in a blinded fashion with either bimagrumab (DI + Bim), clenbuterol (DI + Clen), 5-HOB (DI + 5-HOB), or PBS (DI + PBS). Sham-injured rats underwent sham PNC + VD and received PBS (sham + PBS). After 2 wk of treatment, rats were anesthetized for LPP and external urethral sphincter electromyography recordings. Hindlimb skeletal muscles and pelvic floor muscles were dissected and stained. At the end of 2 wk of treatment, all three treatment groups had a significant increase in body weight and individual muscle weight compared with both sham-treated and sham-injured rats. LPP in DI + Bim rats was significantly higher than LPP of DI + PBS and DI + Clen rats. There were more consistent urethral striated muscle fibers, elastin fibers in the urethra, and pelvic muscle recovery in DI + Bim rats compared with DI + PBS rats. In conclusion, bimagrumab was the most effective for increasing urethral pressure and continence by promoting injured external urethral sphincter and pelvic floor muscle recovery.

Elastin homeostasis is altered with pelvic organ prolapse in cultures of vaginal cells from a lysyl oxidase-like 1 knockout mouse model.

Pelvic organ prolapse (POP) decreases quality of life for many women, but its pathophysiology is poorly understood. We have previously shown that Lysyl oxidase-like 1 knockout (Loxl1 KO) mice reliably prolapse with age and increased parity, similar to women. Both this model and clinical studies also indicate that altered elastin metabolism in pelvic floor tissues plays a role in POP manifestation, although it is unknown if this is a cause or effect. Using Loxl1 KO mice, we investigated the effects of genetic absence of Loxl1, vaginal parity, and presence of POP on the expression of genes and proteins key to the production and regulation of elastic matrix. Cultured cells isolated from vaginal explants of mice were assayed with Fastin for elastic matrix, as well as RT-PCR and Western blot for expression of genes and proteins important for elastin homeostasis. Elastin synthesis significantly decreased with absence of LOXL1 and increased with parity (p < .001), but not with POP. Cells from prolapsed mice expressed significantly decreased MMP-2 (p < .05) and increased TIMP-4 (p < .05). The results suggest changes to elastin structure rather than amounts in prolapsed mice as well as poor postpartum elastin turnover, resulting in accumulation of damaged elastic fibers leading to abnormal tropoelastin deposition. POP may thus, be the result of an inability to initiate the molecular mechanisms necessary to clear and replace damaged elastic matrix in pelvic floor tissues after vaginal birth.

On the mechanical response of the actomyosin cortex during cell indentations.

A mechanical model is presented to analyze the mechanics and dynamics of the cell cortex during indentation. We investigate the impact of active contraction on the cross-linked actin network for different probe sizes and indentation rates. The essential molecular mechanisms of filament stretching, cross-linking and motor activity, are represented by an active and viscous mechanical continuum. The filaments behave as worm-like chains linked either by passive rigid linkers or by myosin motors. In the first example, the effects of probe size and loading rate are evaluated using the model for an idealized rounded cell shape in which properties are based on the results of parallel-plate rheometry available in the literature. Extreme cases of probe size and indentation rate are taken into account. Afterward, AFM experiments were done by engaging smooth muscle cells with both sharp and spherical probes. By inverse analysis with finite element software, our simulations mimicking the experimental conditions show the model is capable of fitting the AFM data. The results provide spatiotemporal dependence on the size and rate of the mechanical stimuli. The model captures the general features of the cell response. It characterizes the actomyosin cortex as an active solid at short timescales and as a fluid at longer timescales by showing (1) higher levels of contraction in the zones of high curvature; (2) larger indentation forces as the probe size increases; and (3) increase in the apparent modulus with the indentation depth but no dependence on the rate of the mechanical stimuli. The methodology presented in this work can be used to address and predict microstructural dependence on the force generation of living cells, which can contribute to understanding the broad spectrum of results in cell experiments.

A Cdh1-FoxM1-Apc axis controls muscle development and regeneration.

Forkhead box M1 (FoxM1) transcriptional factor has a principal role in regulating cell proliferation, self-renewal, and tumorigenesis. However, whether FoxM1 regulates endogenous muscle development and regeneration remains unclear. Here we found that loss of FoxM1 in muscle satellite cells (SCs) resulted in muscle atrophy and defective muscle regeneration. FoxM1 functioned as a direct transcription activator of adenomatous polyposis coli (Apc), preventing hyperactivation of wnt/ß-catenin signaling during muscle regeneration. FoxM1 overexpression in SCs promoted myogenesis but impaired muscle regeneration as a result of spontaneous activation and exhaustion of SCs by transcriptional regulation of Cyclin B1 (Ccnb1). The E3 ubiquitin ligase Cdh1 (also termed Fzr1) was required for FoxM1 ubiquitylation and subsequent degradation. Loss of Cdh1 promoted quiescent SCs to enter into the cell cycle and the SC pool was depleted by serial muscle injuries. Haploinsufficiency of FoxM1 ameliorated muscle regeneration of Cdh1 knock-out mice. These data demonstrate that the Cdh1-FoxM1-Apc axis functions as a key regulator of muscle development and regeneration.

Role of lysyl oxidase like 1 in regulation of postpartum connective tissue metabolism in the mouse vagina†.

Pelvic organ prolapse (POP) in lysyl oxidase like-1 knockout (Loxl1 KO) mice occurs primarily in parous mice and is rare in nulliparous mice. We determined the effect of Loxl1 deficiency on postpartum regulation of connective tissue metabolism genes and degradative enzyme activity in the vagina at 20 days gestation or 4 h, 48 h, 7 days, 15 days, 25 days, 7 weeks, or 12 weeks postpartum. Nulliparous Loxl1 KO and wildtype (WT) mice aged 11, 18, or 23 weeks were controls. Gene expression and enzyme activity were assessed using real-time quantitative reverse transcription PCR and fluorescein conjugated gelatin zymography, respectively. Parity, but not aging, had a significant influence on gene expression both with time postpartum and between KO and WT mice. Mmp2, Timp1, Timp2, Timp3, Timp4, Col1a1, Col3a1, Acta2, and Bmp1 were differentially expressed between KO and WT mice. Correlational analysis of gene-gene pairs revealed 10 significant differences between parous KO and WT groups, 5 of which were due to lack of co-expression of Bmp1 in KO mice. The overall enzyme activity that could be attributed to MMPs was significantly higher in WT compared to KO mice both 25 days and 12 weeks postpartum, and MMP activity was significantly lower 15 days and 25 days postpartum compared to KO nulliparous controls, but not WT. These findings suggest that Loxl1 deficiency combined with parity has a significant impact on postpartum regulation of connective tissue metabolism, particularly as it relates to co-expression of Bmp1 and altered proteolytic activity.