Biology subjects

Bu, J.

Publications and source records attributed to Bu, J..

7 recordsLinked to original sources

bioRxiv2024

Huntingtin is an RNA-binding protein and participates in NEAT1-mediated paraspeckles

AbstractHuntingtin protein, mutated in Huntington disease, is implicated in nucleic acid- mediated processes, yet evidence for direct huntingtin-nucleic acid interaction is limited. Here we show wildtype and mutant huntingtin co-purify with nucleic acids, primarily RNA, and interact directly with G-rich RNAs in in vitro assays. Huntingtin RNA immunoprecipitation sequencing from patient-derived fibroblasts and neuronal progenitor cells expressing wildtype and mutant huntingtin revealed NEAT1 as a significantly enriched transcript. Altered NEAT1 levels were evident in Huntingtons disease cells and postmortem brain tissues, and huntingtin knockdown decreased NEAT1 levels. Huntingtin co-localized with NEAT1 in paraspeckles, and we identified a high-affinity RNA motif preferred by huntingtin. This study highlights NEAT1 as a novel huntingtin interactor, demonstrating huntingtins involvement in RNA-mediated functions and paraspeckle regulation. One-Sentence SummaryHTT is an RNA-binding protein that interacts with G-rich sequences, including those in the paraspeckle lncRNA NEAT1.

cell biology↗

bioRxiv2023

Establishment of hairy root culture and its genetic transformation of Stephania tetrandra S. Moore for production of BIAs

Metabolic engineering improvement of plants will play an essential role in future agriculture, but this largely depends on the establishment of genetic transformation. Stephania tetrandra S. Moore is a traditional Chinese medicine used for rheumatalgia that accumulates benzylisoquinoline alkaloids as its main active ingredients. Wild or farmed plants have remained the main source of these essential medicines, resulting in supply pressure due to the scarcity of wild plant resources and the slow growth rate in cultivation. Here, we constructed Agrobacterium rhizogenes (C58C1)-mediated hairy root culture and a co-transformation system in S. tetrandra to obtain a new source of bisbenzylisoquinoline alkaloids production. We show that the biomass of the hairy roots increased by 10-fold, and the content of tetrandrine reached 8.382 {+/-} 0.160 mg/g DW after 50 days of cultivation. In addition, overexpression of (R, S)-norcoclaurine 6-O-methyltransferase (6OMT) gene or treatment of hairy roots with methyl jasmonate (MJ) increased protoberberine alkaloid content. This work provides a method of obtaining hairy roots and a genetic transformation system for S. tetrandra, not only broadening the access to S. tetrandra resources, but also laying a foundation for further elucidation of the biosynthesis of tetrandrine and related alkaloids.

plant biology↗

bioRxiv2023

Piezo1-dependent regulation of pericyte proliferation by blood flow during brain vascular development

Blood flow is known to regulate cerebrovascular development through acting on vascular endothelial cells (ECs). As an indispensable component of the cerebrovascular unit, brain pericytes physically couple with ECs with the highest density in the body and play vital roles in blood-brain barrier integrity maintenance and neurovascular coupling. However, it remains unclear whether blood flow affects the development of brain pericytes. Here, we report that blood flow can promote brain pericyte proliferation, which depends on the mechanosensitive ion channel Piezo1. Using in vivo time-lapse imaging of larval zebrafish, we monitored the developmental dynamics of brain pericytes and found that they proliferated to expand their population and increase their coverage on brain vessels. In combination with pharmacological and genetic approaches, we demonstrate that the proliferation of brain pericytes can be enhanced by increased blood flow through Piezo1 expressed in ECs. Furthermore, EC-intrinsic Notch signaling was found to be downstream of Piezo1 for the blood flow regulation of brain pericyte proliferation. Thus, our findings reveal an important role of blood flow for pericyte proliferation, extending the functional spectrum of hemodynamics on the development of cerebral vasculature.

developmental biology↗

bioRxiv2022

Dalpiciclib Partially Abrogates ER Signaling Activation Induced by Pyrotinib In HER2+HR+ Breast Cancer

BackgroundRecent evidences from clinical trials (NCT04486911) revealed that the combination of pyrotinib, letrozole and dalpiciclib exerted optimistic therapeutic effect to treat HER2+HR+ breast cancer, however, the underlying molecular mechanism remained further investigation. MethodsThrough the drug sensitivity test, the drug combination efficacy of pyrotinib, tamoxifen and dalpiciclib to BT474 cells were tested. The underlying molecular mechanisms were investigated using immunofluorescence, western blot analysis, immunohistochemical staining and cell cycle analysis. Potential risk factor which may indicate the responsiveness to drug treatment in HER2+/HR+ breast cancer was selected out using RNA-sequence and tested using immunohistochemical staining and in vivo drug susceptibility test. ResultsWe found that pyrotinib combined with dalpiciclib exerted better cytotoxic efficacy than pyrotinib combined with tamoxifen in BT474 cells. Degradation of HER2 could enhance ER nuclear transportation, activating ER signaling pathway in BT474 cells whereas dalpiciclib could partially abrogate this process. This may be the underlying mechanism by which combination of pyrotinib, tamoxifen and dalpiciclib exerted best cytotoxic effect. Furthermore, CALML5 was revealed to be a risk factor in the treatment of HER2+/HR+ breast cancer and the usage of dalpiciclib might overcome this. ConclusionOur study provided evidence that the usage of dalpiciclib in the treatment of HER2+/HR+ breast cancer could partially abrogate the estrogen signaling pathway activation caused by anti-HER2 therapy and revealed that CALML5 could serve as a risk factor in the treatment of HER2+/HR+ breast cancer. FundingThis study was supported by the National Natural Science Foundation of China (#U20A20381, #81872159)

cancer biology↗

bioRxiv2022

Temporal responses of bumblebee gustatory neurons encode sugar identity

The sense of taste permits the recognition of valuable nutrients and the avoidance of potential toxins. Models of gustatory coding propose that within modalities (e.g. sweet, bitter, etc.), taste ligands are not distinct stimuli. However, these models are based on data from mice or flies that have omnivorous, non-specialist diets. A specialist feeder might, however, be expected to have acuity within modality if stimulus resolution was critical to survival. Previously, we found that bumblebees have a specialized mechanism for sensing sugars whereby two gustatory receptor neurons (GRNs) within the galeal sensilla of the bees mouthparts exhibit burst of spikes. Here, we show that the temporal firing patterns of these GRNs separate sugars into four distinct groups that correlate with sugar nutritional value and palatability. We also identified a third GRN that responded to stimulation with relatively high concentrations of fructose, sucrose, and maltose. Sugars that were non-metabolizable or toxic suppressed the responses of bursting GRNs to sucrose. These abilities to encode information about sugar value are a refinement to the bumblebees sense of sweet taste that could be an adaptation that enables precise calculations of the nature and nutritional value of floral nectar.

neuroscience↗

bioRxiv2021

Dalpiciclib and Pyrotinib Exert Synergistic Antitumor Effects in Triple Positive Breast Cancer

BackgroundThe therapeutic benefit of the standard combination of anti-HER2 and chemotherapy in triple-positive breast cancer (TPBC) is limited even after the addition of endocrine therapy to the regimen. Therefore, treatment optimization is required urgently. MethodsThrough the drug sensitivity test, the drug combination efficacy of anti-HER2 drug, endocrine drug and CDK4/6 inhibitor to BT474 cells were tested. The underlying molecular mechanisms were investigated using immunofluorescence, western blot analysis, immunohistochemical staining and cell cycle analysis. Potential biomarker which may indicate the responsiveness to drug treatment in triple positive breast cancer was selected out using RNA-sequence and tested using immunohistochemical staining. ResultsWe found that pyrotinib combined with dalpiciclib showed better efficacy than pyrotinib combined with tamoxifen in BT474 cells. Degradation of HER2 could enhance ER nuclear transportation, whereas cell cycle blockers could reverse this process. This may be the underlying mechanism by which the addition of dalpiciclib was more beneficial than the addition of pyrotinib plus tamoxifen. Furthermore, CALML5 was revealed to be a potential indicator of responsiveness to anti-HER2 therapy plus CDK4/6 inhibition in triple positive breast cancer. ConclusionOur study provided evidence for the introduction of CDK4/6 inhibitor in the treatment of TPBC and indicated that the combination of anti-HER2 therapy and cell cycle blockers may be a better strategy for TPBC treatment. FundingThis study was supported by the National Natural Science Foundation of China (#U20A20381, #81872159)

cell biology↗

bioRxiv2021

Alpha oscillatory activity causally linked to working memory retention: insights from online phase-locking closed-loop transcranial alternating current stimulation (tACS)

Although previous studies have reported correlations between alpha oscillations and the "retention" sub-process of working memory (WM), causal evidence has been limited in human neuroscience due to the lack of delicate modulation of human brain. Conventional tACS is not suitable for demonstrating the causal evidence for parietal alpha oscillations in WM retention because of its inability to modulate brain oscillations within a short period (i.e., the retention sub-process). Here, we developed an online phase-corrected closed-loop transcranial alternating current stimulation (tACS) system capable of precisely correcting for the phase differences between tACS and concurrent endogenous oscillations. This system permits both up- and down-regulation of brain oscillations at the target stimulation frequency within a short stimulation period, and is here applied to empirically demonstrate that parietal alpha oscillations causally relate to WM retention. Our experimental design included both in-phase and anti-phase alpha-tACS applied to 39 participants during the retention sub-processes of a modified Sternberg paradigm. Compared to in-phase alpha-tACS, anti-phase alpha-tACS decreased both WM performance and alpha activity. Moreover, the in-phase tACS-induced changes in WM performance were positively correlated with alpha oscillatory activity. These findings strongly support a causal link between alpha oscillations and WM retention, and illustrate the broad application prospects of phase-corrected tACS.

neuroscience↗