Biology subjects

Guan, X.

Publications and source records attributed to Guan, X..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

A molecularly defined brain circuit module for regulating the panic-like defensive state

Panic is an episode of strong defensive state, characterized by intense fear and severe physical symptoms such as elevated cardiorespiratory activities. How the brain generates panic state remains poorly understood. Here, we developed a robot-based experimental paradigm to evoke panic-like defensive state in mice. When stimulated by the robot, the mice exhibited jumping escapes and elevated cardiorespiratory activities. With this paradigm, we identified Cbln2-expressing (Cbln2+) neurons in the posterior hypothalamic nucleus (PHN) as a key neuronal population essential for the induction of panic-like defensive state. Activation of Cbln2+ PHN neurons induced behavioral and physical symptoms of panic-like defensive state. These neurons were strongly activated by noxious mechanical stimuli and encode jumping escape vigor. They were synaptically innervated by anxiety-associated brain areas and provoked panic-like defensive state via their projection to the periaqueductal gray. Together, our results reveal a molecularly defined circuit module that regulates the panic-like defensive state in mice.

neuroscience↗

bioRxiv2024

A Wearable Spiral Ultrasound Patch for Focused Ultrasound Peripheral Neuromodulation of Diabetic Neuropathic Pain

Diabetic foot disease, a severe complication of diabetes, frequently results in diabetic neuropathic pain, which diminishes quality of life and increases the risk of amputation. Current treatment options are limited in their effectiveness and can present adverse effects. We have demonstrated a first-of-its-kind wearable spiral ultrasound patch for focused ultrasound peripheral neuromodulation to alleviate diabetic neuropathic pain. This innovative, stretchable ultrasound device reliably delivers focused ultrasound to peripheral nerves. The devices ultrasound elements are arranged in a phyllotaxis spiral pattern, enhancing transmitted acoustic focus performance and minimizing grating and side lobes. Using a diabetic foot rat model, we confirmed peripheral neuropathy through behavioral assessments of mechanical allodynia and heat hyperalgesia, which showed significant pain relief after two weeks of ultrasound treatment. Additionally, nerve conduction velocity improved. Biological safety tests indicated no adverse effects on nerve tissues or cells. Our approach offers a non-invasive solution for managing diabetic neuropathic pain and provides critical insights into its underlying mechanisms, paving the way for more effective therapies.

bioengineering↗

bioRxiv2024

An Investigation into Mechanomyography for Signal Extraction and Classification of Human Lower Limb Activity

To mitigate the difficulties associated with the extraction of Mechanomyography (MMG) signals from raw Accelerometer (ACC) data and the subsequent classification of human lower limb activities based on MMG signals, the Feature Mode Decomposition (FMD) algorithm has been utilized for the isolation of the MMG signal. Simultaneously, surface Electromyography (sEMG) signals were recorded to perform correlation analyses, thereby validating the effectiveness of the extracted Mechanomyography (MMG) signals. The results demonstrate that the envelope entropy derived from the FMD was the lowest among the observed values, and the composite signal obtained via FMD displayed the highest correlation with the sEMG signal. This indicates that FMD is capable of efficiently isolating the MMG signal while maintaining the maximal quantity of muscle contraction data. To address the challenge of classifying human lower limb activities, a comprehensive feature extraction procedure was implemented, resulting in the derivation of 448 unique features from multi-channel mechanomyography (MMG) signals. Subsequently, Kernel Principal Component Analysis (KPCA) was employed to diminish the feature sets dimensionality. This was succeeded by the deployment of a Temporal Convolutional Network integrated with an Attention mechanism (TCN-Attention) to train the classification model. Additionally, an enhanced Northern Goshawk Optimization Algorithm was leveraged for optimization purposes. The findings indicate that FMD exhibited the minimum envelope entropy value of 8.13, concurrently attaining the maximum correlation coefficient of 0.87 between MMG and sEMG signals. Significantly, the SCNGO-TCN-Attention model demonstrated superior classification accuracy, attaining an exceptional accuracy rate of 98.44%.

bioengineering↗

bioRxiv2024

Mitophagy Facilitates Cytosolic Proteostasis to Preserve Cardiac Function

BackgroundProtein quality control (PQC) is critical for maintaining sarcomere structure and function in cardiac myocytes, and mutations in PQC pathway proteins, such as CRYAB (arginine to glycine at position 120, R120G) and BAG3 (proline to lysine at position 209, P209L) induce protein aggregate pathology with cardiomyopathy in humans. Novel observations in yeast and mammalian cells demonstrate mitochondrial uptake of cytosolic protein aggregates. We hypothesized that mitochondrial uptake of cytosolic protein aggregates and their removal by mitophagy, a lysosomal degradative pathway essential for myocardial homeostasis, facilitates cytosolic protein quality control in cardiac myocytes. MethodsMice with inducible cardiac myocyte specific ablation of TRAF2 (TRAF2icKO), which impairs mitophagy, were assessed for protein aggregates with biochemical fractionation and super-resolution imaging in comparison to floxed controls. Induced pluripotent stem cell (iPSC)-derived cardiac myocytes with R120G knock-in to the CRYAB locus were assessed for localization of the CRYAB protein. Transgenic mice expressing R120G CRYAB protein (R120G-TG) were subjected to both TRAF2 gain-of-function (with AAV9-cardiac Troponin T promoter-driven TRAF2 transduction) and TRAF2 loss-of-function (with tamoxifen-inducible ablation of one Traf2 allele) in cardiac myocytes to determine the effect of mitophagy modulation on cardiac structure, function, and protein aggregate pathology. ResultsCardiomyocyte-specific ablation of TRAF2 results accumulation of mitochondrial and cytosolic protein aggregates and DESMIN mis-localization to protein aggregates. Isolated mitochondria take up cardiomyopathy-associated aggregate-prone cytosolic chaperone proteins, namely arginine to glycine (R120G) CRYAB mutant and proline to lysine (P209L) BAG3 mutant. R120G-CRYAB mutant protein increasingly localizes to mitochondria in human and mouse cardiomyocytes. R120G-TG mice demonstrate upregulation of TRAF2 in the mitochondrial fraction with increased mitophagy as compared with wild type. Adult-onset inducible haplo-insufficiency of TRAF2 resulted in accelerated mortality, impaired left ventricular systolic function and increased protein aggregates in R120G-TG mice as compared with controls. Conversely, AAV9-mediated TRAF2 transduction in R120G-TG mice reduced mortality and attenuated left ventricular systolic dysfunction, with reduced protein aggregates and restoration of normal localization of DESMIN, a cytosolic scaffolding protein chaperoned by CRYAB, as compared with control AAV9-GFP group. ConclusionsTRAF2-mediated mitophagy in cardiac myocytes facilitates removal of cytosolic protein aggregates and can be stimulated to ameliorate proteotoxic cardiomyopathy.

cell biology↗

bioRxiv2024

Baicalein ameliorates experimental ulcerative colitis recurrency by downregulating neonatal Fc receptor via the NF-κB signaling pathway

Ulcerative colitis (UC) is a chronic autoimmune disease (AID) that causes mild to moderate, unpredictable symptoms, including diarrhea and abdominal pain. Against neonatal Fc receptors (FcRn) has been proven a unique AID treatment strategy by decreasing the effects of pathogenic autoantibody. Our previous study revealed that FcRn inhibition is beneficial in UC treatment through reducing colonic neutrophil extracellular traps (NET) formation via accelerating serum anti-neutrophil cytoplasm antibodies (ANCA) clearance. In this study, we initially confirmed the specific impact of downregulating FcRn in preventing UC relapse by injecting rAAV, that carrying Fcgrt-shRNA, in mice. Next, we investigated the inhibition effects and regulation mechanisms of baicalein (BCL) on FcRn and assessed its capacity to withstand UC recurrence using NCM460 cells and dextran sodium sulfate-induced mice models by determining the expression of FcRn and its related transcription factors. We also measured colonic NET-associated protein (NAP) expression and serum concentrations of IgG, ANCA, TNF-, IL-1{beta}, and c-reactive protein (CRP). UC inflammation severity was determined using the disease activity index (DAI) and histopathological score (HS). BCL treatment remarkably decreased the mRNA and protein contents of FcRn, p50, and p65 but did not impact STAT1 expression and the phosphorylation of I{kappa}B and STAT1. Long-term BCL administration inhibited colonic FcRn expression and reduced serum ANCA levels, colonic NAPs expression, serum inflammation-related indexes (including TNF-, IL-1{beta}, and CRP), DAI, and HS scores in UC mice during inflammation relapse better than salazosulfapyridine. Our study indicates that BCL ameliorates UC recurrency by inhibiting FcRn expression via p50/p65 heterodimer-mediated NF-{kappa}B signaling. Chemical compoundsChemical compounds studied in this article were listed below: Baicalein (PubChem CID: 5281605); Salazosulfapyridine (PubChem CID: 5339).

pharmacology and toxicology↗

bioRxiv2024

Reproductive state controls transcription in the murine liver, with implications for breast cancer liver metastasis

Liver biology is functionally linked to lactation, as liver size and metabolic output increase during lactation to support synthesis of breast milk. Upon weaning, the rodent liver returns to baseline homeostasis via hepatocyte cell death, in a process considered liver involution. To explore liver biology changes across a lactation-wean cycle, we employed transcriptomic profiling. We identified elevated hepatocyte proliferation and anabolic metabolism gene signatures during lactation, consistent with the liver being a major producer of substrates needed for milk production. Rapid loss of these capacities upon weaning correlated with catabolic metabolism, lysosomal-mediated cell death, and an influx of immune suppressive cells. Furthermore, we identified that the transcriptional profiles associated with liver involution share similarities with the gene expression patterns of liver pre-metastatic niches. This work identifies features of reproductive control of liver biology that sets a foundation for better understanding the potential role of the liver in maternal health.

cancer biology↗

bioRxiv2024

α/β-Hydrolase domain-containing 6 (ABHD6) accelerates the desensitization and deactivation of TARP γ-2-containing AMPA receptors

AMPA receptors (AMPARs) mediate most of the fast excitatory synaptic transmission in the mammalian brain. Their efficacy in responding to presynaptic glutamate release depends on their kinetics, which are determined by AMPARs and their auxiliary subunit composition. /{beta}-Hydrolase domain-containing 6 (ABHD6) is an AMPAR auxiliary subunit that has been shown to negatively regulate the surface delivery of AMPARs and AMPAR-mediated currents. Overexpression of ABHD6 has been shown to decrease the rising slope and increase the decay {tau} of mEPSCs. However, whether ABHD6 is involved in regulating AMPAR kinetics remains unclear. Here, we found that ABHD6 itself had no effect on the gating kinetics of GluA1 and GluA2(Q) containing homomeric receptors. However, in the presence of the auxiliary subunit TARP {gamma}-2, ABHD6 accelerated the deactivation and desensitization of both GluA1 and GluA2(Q) containing homomeric receptors independent of their splicing isoforms (flip and flop) and the editing isoforms of GluA2 (R or G at position 764), except for the deactivation of GluA2(Q)i-G isoform. Besides, the recovery from desensitization of GluA1 with flip splicing isoform was slowed by the co-expression of ABHD6 in the presence of TARP {gamma}-2. Furthermore, ABHD6 accelerated the deactivation and desensitization of GluA1i/GluA2(R)i-G and GluA2(R)i-G/GluA3(R)i heteromeric receptors in the presence of TARP {gamma}-2. We also found that ABHD6-knockout neurons displayed slower deactivation and desensitization. Therefore, these results demonstrate that ABHD6 regulates AMPAR gating kinetics in a TARP {gamma}-2-dependent manner. SIGNIFICANCE STATEMENTThe efficacy of AMPARs in responding to presynaptic glutamate release depends on their kinetics, including deactivation, desensitization, and recovery from desensitization, which are determined by AMPARs and their auxiliary subunit composition. Using ultra-fast application of glutamate and outside-out patch recordings, we found that, in the presence of the auxiliary subunit TARP {gamma}-2, ABHD6 accelerated the deactivation and desensitization of GluA1i/GluA2(R)i-G and GluA2(R)i-G/GluA3(R)i heteromeric receptors and GluA1 and GluA2(Q) containing homomeric receptors independent of their splicing isoforms (flip and flop) and the editing isoforms of GluA2 (R or G at position 764), except for the deactivation of GluA2(Q)i-G isoform. In ABHD6 knockout neurons, we also observed slower deactivation and desensitization. These results demonstrated that ABHD6 regulates AMPAR gating kinetics in a TARP {gamma}-2-dependent manner.

neuroscience↗

bioRxiv2024

Pathological axonal enlargement in connection with amyloidosis, lysosome destabilization and hemorrhage is a major defect in the Alzheimer's disease

AbstractAlzheimers disease (AD) is a multi-amyloidosis disease with A{beta} deposits in the cerebral blood vessels, microaneurysms and senile plaques. How A{beta} amyloidosis affects axon pathology is not well-examined. We studied A{beta}-related axonal phenotypes with histochemistry, immunohistochemistry and fluorescence imaging methods. Widespread axonal amyloidosis with distinctive axonal enlargement was observed in AD. A{beta}-positive axon diameters in AD brains were 1.72 times of control brain axons by average. Axonal amyloidosis also associated with MAP2 reduction, Tau phosphorylation, lysosome destabilization and hemorrhagic markers such as ApoE, HBA, HbA1C and Hemin. Lysosome destabilization in AD was also clearly identified in the neural soma, associating with the co-expression of A{beta} and Cathepsin D, HBA, ACTA2 and ColIV, implicating exogeneous hemorrhagic protein intake might influence neural lysosome stability. The data showed that A{beta}-containing lysosomes were 2.23 times as large as the control lysosomes. Furthermore, under rare conditions, axon breakages were observed, which likely resulted in Wallerian degeneration. In summary, axonal enlargement associated with amyloidosis, chronic microhemorrhage and lysosome destabilization is a major defect in Alzheimers disease.

cell biology↗

bioRxiv2024

Super Enhancer-driven LncRNA UNC5B-AS1 Inhibits Inflammatory Phenotypic Transition in Smooth Muscle Cells via Lactylation Modification

BackgroundThe phenotypic transition of pulmonary artery smooth muscle cells (PASMCs) is a central pathological alteration in pulmonary artery remodeling that contributes to pulmonary hypertension (PH). The specific role of long noncoding RNAs (lncRNAs), especially super enhancer (SE)-driven lncRNAs, in the phenotypic transformation of PASMCs induced by hypoxia remains unclear. The objective of this study is to determine the mechanistic role of the super enhancer-driven LncRNA UNC5B-AS1 in phenotypic transformation of PASMCs and hypoxia-induced vascular remodeling. MethodsThe lncRNA UNC5B-AS1 regulated by super-enhancers was identified in hypoxic human PASMCs through RNA sequencing and H3K27ac ChIP sequencing. Overexpression of lncRNA UNC5B-AS1 in human PASMCs was performed to elucidate its role in the pathogenesis of PH. A conserved functional fragment of lncRNA UNC5B-AS1 was used for the treatment of mouse PH. ResultsIn PASMCs, we have identified a SE-driven lncRNA called UNC5B-AS1 that regulates phenotype transition. It is transcriptionally activated by the transcription factor FOXP3. We demonstrate that UNC5B-AS1, as a molecular scaffold in mitochondria, stabilizes the interaction between LRPPRC, which is rich in leucine, and oxidative respiratory chain complex IV. This complex regulates the lactylation modification level of upstream promoter regions of inflammatory genes IL-1{beta}, IL-6, and TNF- by influencing the glycolytic pathway in PASMCs under hypoxic conditions, ultimately affecting the inflammatory phenotype transition of PASMCs. ConclusionsOur findings identify the SE-driven lncRNA UNC5B-AS1 as a novel regulatory factor in hypoxia-induced phenotypic switch of PASMCs, and suggest that overexpression of UNC5B-AS1 may represent a promising therapeutic strategy for PH. HighlightsThe long non-coding RNA UNC5B-AS1, regulated by super-enhancers (SE), is downregulated in hypoxic PASMCs, and regulates PASMC phenotype transition through glycolysis. The super-enhancer region of lncRNA UNC5B-AS1 recruits the transcription factor FOXP3 to its promoter region, forming a chromatin loop to regulate its expression. The lncRNA UNC5B-AS1 acts as a molecular scaffold stabilizing the interaction between LRPPRC and mitochondrial complex IV. The lactate generated by glycolysis activation induces lactylation modification of histones at the IL-1{beta}, IL-6, and TNF- promoters, leading to the inflammatory phenotype transition of PASMCs. Overexpression of lncRNA UNC5B-AS1 conserved fragment reversed SuHx-induced PH in mice. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=121 SRC="FIGDIR/small/593065v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@864576org.highwire.dtl.DTLVardef@13a5fe4org.highwire.dtl.DTLVardef@16d7884org.highwire.dtl.DTLVardef@35d50_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2024

N-Myc and STAT Interactor is an endometriosis suppressor.

In patients with endometriosis, refluxed endometrial fragments evade host immunosurveillance, developing into endometriotic lesions. However, the mechanisms underlying this evasion have not been fully elucidated. N-Myc and STAT Interactor (NMI) have been identified as key players in host immunosurveillance, including interferon (IFN)-induced cell death signaling pathways. NMI levels are markedly reduced in the stromal cells of human endometriotic lesions due to modulation by the Estrogen Receptor beta/Histone Deacetylase 8 axis. Knocking down NMI in immortalized human endometrial stromal cells (IHESCs) led to elevated RNA levels of genes involved in cell-to-cell adhesion and extracellular matrix signaling following IFNA treatment. Furthermore, NMI knockdown inhibited IFN-regulated canonical signaling pathways, such as apoptosis mediated by Interferon Stimulated Gene Factor 3, and necroptosis upon IFNA treatment. In contrast, NMI knockdown with IFNA treatment activated non-canonical IFN-regulated signaling pathways that promote proliferation, including {beta}-Catenin and AKT signaling. Moreover, NMI knockdown in IHESCs stimulated ectopic lesions growth in mouse endometriosis models. Therefore, NMI is a novel endometriosis suppressor, enhancing apoptosis and inhibiting proliferation and cell adhesion of endometrial cells upon IFN exposure.

molecular biology↗

bioRxiv2024

Neuropathic pain in a chronic CNS injury model is mediated by CST-targeted spinal interneurons

Chronic neuropathic pain is a persistent and debilitating outcome of traumatic central nervous system injury, affecting up to 80% of individuals with chronic injury. Post-injury pain is refractory to clinical treatments due to the limited understanding of the brain-spinal cord circuits that underlie pain signal processing. The corticospinal tract (CST) plays critical roles in sensory modulation during skilled movements and tactile sensation; however, a direct role for the CST in injury-associated neuropathic pain is unclear. Here we show that complete, selective CST transection at the medullary pyramids leads to hyperexcitability within lumbar deep dorsal horn and hindlimb allodynia in chronically injured adult mice. Chemogenetic regulation of CST-targeted lumbar spinal interneurons demonstrates that dysregulation of activity in this circuit underlies the development of tactile allodynia in chronic injury. Our findings shed light on an unrecognized circuit mechanism implicated in CNS injury-induced neuropathic pain and provide a novel target for therapeutic intervention.

neuroscience↗

bioRxiv2023

Computationally Driven Discovery and Characterization of SIRT3 Activating Compounds that Fully Recover Catalytic Activity under NAD+ Depletion

Mammalian sirtuins (SIRT1-SIRT7) are a family of nicotinamide adenine dinucleotide (NAD+)-dependent protein deacylases that play critical roles in lifespan and age-related diseases. The physiological importance of sirtuins has stimulated intense interest in designing sirtuin activating compounds. However, except for allosteric activators of SIRT1-catalyzed reactions that are limited to specific substrates, methodologies for the rational design of sirtuin activating compounds -- including compounds that activate mitochondrial sirtuins implicated in the age-related decline of cellular metabolism -- have been lacking. Here, we use computational high-throughput screening methodologies and a biophysical model for activation of the major mitochondrial sirtuin SIRT3 to identify novel small molecule activators of the human SIRT3 enzyme from a 1.2 million compound library. Unlike previously reported SIRT3 activators like Honokiol, which only transiently upregulate SIRT3 under non-steady state conditions and reduce the steady state catalytic efficiency of the enzyme, several of the novel compounds identified here are potent SIRT3 activators in both the steady and non-steady states. Two such compounds can almost double the catalytic efficiency of the enzyme with respect to NAD+, which would be sufficient to almost entirely compensate for the loss in SIRT3 activity that occurs due to the reduction in mitochondrial coenzyme concentration associated with aging, and display AC50s (concentrations of half-maximal activation) as low as 100 nM. The current work thus reports first-in-class, non-allosteric steady state activators that activate SIRT3 through a novel, mechanism-based mode of activation and that may be developed further for therapeutic applications.

biochemistry↗

bioRxiv2023

Distinct eLPB ChAT projections for methamphetamine anxiety and relapse

Choline acetyltransferase-positive neurons in the external lateral parabrachial nucleus (eLPBChAT) send projections to PKC{delta}-positive (PKC{delta}+) neurons in lateral portion of central nucleus of amygdala (lCeAPKC{delta}) and oval portion of bed nucleus of the stria terminalis (ovBNSTPKC{delta}), forming eLPBChAT-lCeAPKC{delta} and eLPBChAT-ovBNSTPKC{delta} pathways. At least in part, the eLPBChAT neurons positively innervate lCeAPKC{delta} and ovBNSTPKC{delta} through regulating synaptic elements of presynaptic acetylcholine (Ach) release and postsynaptic nicotinic acetylcholine receptors (nAChRs). Methamphetamine (METH) withdrawal anxiety and METH-primed reinstatement of conditioned place preference (CPP) recruit eLPBChAT-lCeAPKC{delta} pathway and eLPBChAT-ovBNSTPKC{delta} pathway in male METH-exposed mice, respectively.

neuroscience↗

bioRxiv2023

Cortical and behavioural tracking of rhythm in music: Effects of pitch predictability, enjoyment, and expertise

The cortical tracking of stimulus features (such as the sound envelope) is a crucial neural requisite of how we process continuous music. We here tested whether cortical tracking of the beat, typically related to rhythm processing, is modulated by pitch predictability and other top-down factors. Participants listened to tonal (high pitch predictability) and atonal (low pitch predictability) music while undergoing EEG, and we analysed their cortical tracking of the acoustic envelope. Interestingly, cortical envelope tracking was stronger while listening to atonal than tonal music, likely reflecting listeners violated pitch expectations. Envelope tracking was also stronger with more expertise and enjoyment. Furthermore, we analysed cortical tracking of pitch surprisal (using IDyOM) and show that listeners expectations for tonal and atonal music match those computed by the IDyOM model, with higher surprisal (prediction errors) for atonal than tonal music. Behaviourally, we measured participants ability to tap along to the beat of tonal and atonal sequences in two experiments. In both experiments, finger-tapping performance was better in the tonal than the atonal condition, indicating a positive effect of pitch predictability on behavioural rhythm processing. Cortical envelope tracking predicted tapping performance for tonal music, as did pitch surprisal tracking for atonal music, indicating that conditions of high and low predictability might impose different processing regimes. We show that cortical envelope tracking, beyond reflecting musical rhythm processing, is modulated by pitch predictability, as well as musical expertise and enjoyment. Taken together, our results show various ways in which those top-down factors impact musical rhythm processing.

neuroscience↗

bioRxiv2023

The impact of size on middle-ear sound transmission in elephants, the largest terrestrial mammal

Elephants have a unique auditory system that is larger than any other terrestrial mammal. To quantify the impact of larger middle ear (ME) structures, we measured 3D ossicular motion and ME sound transmission in cadaveric temporal bones from both African and Asian elephants in response to air-conducted (AC) tonal pressure stimuli presented in the ear canal (PEC). Results were compared to similar measurements in humans. Velocities of the umbo (VU) and stapes (VST) were measured using a 3D laser Doppler vibrometer in the 7-13,000 Hz frequency range, stapes velocity serving as a measure of energy entering the cochlea--a proxy for hearing sensitivity. Below the elephant ME resonance frequency of about 300 Hz, the magnitude of VU/PEC was an order of magnitude greater than in human, and the magnitude of VST/PEC was 5x greater. Phase of VST/PEC above ME resonance indicated that the group delay in elephant was approximately double that of human, which may be related to the unexpectedly high magnitudes at high frequencies. A boost in sound transmission across the incus long process and stapes near 9 kHz was also observed. We discuss factors that contribute to differences in sound transmission between these two large mammals.

physiology↗

bioRxiv2023

Impaired bone morphogenetic protein signaling pathways disrupt decidualization in endometriosis

It is hypothesized that impaired endometrial decidualization contributes to decreased fertility in individuals with endometriosis. To identify the molecular defects that underpin defective decidualization in endometriosis, we subjected endometrial stromal cells from individuals with or without endometriosis to time course in vitro decidualization with estradiol, progesterone, and 8-bromo-cyclic-AMP (EPC) for 2, 4, 6, or 8 days. Transcriptomic profiling identified differences in key pathways between the two groups, including defective bone morphogenetic protein (BMP)/SMAD4 signaling (ID2, ID3, FST), oxidate stress response (NFE2L2, ALOX15, SLC40A1), and retinoic acid signaling pathways (RARRES, RARB, ALDH1B1). Genome-wide binding analyses identified an altered genomic distribution of SMAD4 and H3K27Ac in the decidualized stromal cells from individuals without endometriosis relative to those with endometriosis, with target genes enriched in pathways related to signaling by transforming growth factor {beta} (TGF{beta}), neurotrophic tyrosine kinase receptors (NTRK), and nerve growth factor (NGF)-stimulated transcription. We found that direct SMAD1/5/4 target genes control FOXO, PI3K/AKT, and progesterone-mediated signaling in decidualizing cells and that BMP2 supplementation in endometriosis patient-derived assembloids elevated the expression of decidualization markers. In summary, transcriptomic and genome-wide binding analyses of patient-derived endometrial cells and assembloids identified that a functional BMP/SMAD1/5/4 signaling program is crucial for engaging decidualization.

molecular biology↗

bioRxiv2023

Xylem sap residue in cut-open conduits can affect gas discharge in pneumatic experiments

O_LIConsiderable progress has been made in understanding the mechanisms of embolism formation based on the pneumatic method, which relies on gas discharge measurements. Here, we test the assumption that cut-open conduits are gas-filled when samples are cut at high water potentials. C_LIO_LIWe performed vulnerability curves (VC) with the Pneumatron and analysed sap extraction from cut-open vessels in Citrus branches, while the optical method was applied as a reference method. VCs of 11 additional angiosperms were analysed to generalise our findings. C_LIO_LIWe found an increase in gas discharge during early stages of dehydration, which affected the VC of Citrus. Xylem sap was not absorbed immediately by surrounding tissue in cut Citrus branches. The gas amount discharged increased until all sap residue was absorbed, which was near the turgor loss point. By analysing the slope of VCs, we could correct pneumatic VC, as evidenced by the strong agreement in embolism resistance between the pneumatic and the optical method. C_LIO_LISince residual sap in cut-open conduits of some species could slightly reduce embolism resistance in some species, we propose to apply an easy correction for this novel artefact. Automated measurements with a Pneumatron are also required because of its high time resolution. C_LI

plant biology↗

bioRxiv2023

Aβ-aggregation-generated blue autofluorescence illuminates senile plaques, complex blood and vascular pathologies in the Alzheimer's disease

Senile plaque blue autofluorescence in the Alzheimers disease (AD) was discovered around 40 years ago, however, its impact on AD pathology is not fully examined. We analyzed senile plaques with immunohistochemistry and fluorescence imaging on AD brain pathological sections and also the A{beta} aggregation process in vitro in test tubes. In DAPI or Hoechst staining experiments, the data showed that the nuclear blue fluorescence could only be correctly assigned after subtracting the blue autofluorescence background. The plaque cores have very strong blue autofluorescence which is roughly 2.09 times of average DAPI nuclear staining and roughly 1.78 times of average Hoechst nuclear staining. The composite flower-like structures formed by Cathepsin D lysosomal staining wrapping dense core blue fluorescence should not be considered as central-nucleated neurons filled with defective lysosomes since there was no nuclear staining in the plaque core when the blue autofluorescence was subtracted. Furthermore, the dense cores were shown to be completely lack of nuclear signals by PI staining. The A{beta} aggregation assay indicated that both A{beta} self-oligomers and A{beta}/Hemoglobin (Hb) heterocomplexes had significant blue autofluorescence. However, the blue autofluorescence intensity was not always proportional to the intensity of A{beta} immunostaining. The majority of aggregates in the A{beta}/Hb incubations were sensitive to Proteinase K (PK) digestion while the rest were PK resistant. The blue autofluorescence of A{beta} aggregates not only labels senile plaques but also illustrates red blood cell aggregation, hemolysis, CAA, vascular amyloid plaques, vascular adhesion and microaneurysm. In summary, we conclude that A{beta}-aggregation-generated blue autofluorescence is an excellent amyloid pathology marker in the senile plaques, blood and vascular pathologies in the Alzheimers disease.

cell biology↗