Biology subjects

Pan, D.

Publications and source records attributed to Pan, D..

60 records · Page 4Linked to original sources

bioRxiv2020

Laser capture microdissection-based single-cell RNA sequencing reveals optic nerve crush-related early mRNA alterations in retinal ganglion cells

Retinal ganglion cells (RGC) are the primary cell type injured in a variety of diseases of the optic nerve, and the early changes of RGCs RNA profiling may be important to understand the mechanism of optic nerve injury and axon regeneration. Here we employed the optic nerve crush (ONC) model to explore early mRNA alterations in RGCs using laser capture microdissection (LCM) and single-cell RNA sequencing. We successfully established an optimal LCM protocol using 30 m-thick retinal tissue sections mounted on glass slides and laser pressure catapulting (LPC) to collect RGCs and obtain high-quality RNA for single-cell sequencing. Based on our protocol, we identified 8744 differentially expressed genes that were involved in ONC-related early mRNA alterations in RGCs. Candidate genes included Atf3, Lgals3, LOC102551701, Plaur, Tmem140 and Maml1. The LCM-based single-cell RNA sequencing allowed new insights into the early mRNA changes in RGCs, highlighting new molecules associated with ONC.

neuroscience↗

bioRxiv2019

An antibody drug conjugate targeting a GSTA glycosite-signature epitope of mucin1 expressed by non-small cell lung cancer

BackgroundAntibodies targeting abnormally glycosylated proteins have been ineffective in treating cancer. Antibody-drug conjugates are emerging as an efficient option, which allow specific delivery of drugs into tumors. We and others have dissected the abnormally glycosylated tandem repeat region of MUC1 glycoprotein as three site-specific glycosylated neoantigen peptide motifs (PDTR, GSTA, GVTS) for monoclonal antibody binding. MethodsInternalization of monoclonal antibodies was studied by immunofluorescence staining and colocalization with lysosomal markers in live cells. Antibody positivity in tumor and peritumoral tissue samples were studied by immunohistochemistry. The efficacy of anti-MUC1 ADCs were evaluated with various cancer cell lines and mouse tumor xenograft model. ResultsWe describe an anti-MUC1 ADC by conjugating GSTA neoantigen-specific 16A with monomethyl auristatin E (MMAE). 16A-MMAE showed potent antitumoral efficacy with IC50 ranging from 0.2 to 49.4 nM toward multiple types of cancer cells. In vivo, 16A-MMAE showed dose-dependent inhibition of tumor growth in mouse xenograft of NCI-H838 NSCLC cell line, with minimum effective dose at 1 mg/kg. At the dose of 3 mg/kg, 16A-MMAE did not cause significant toxicity in a transgenic mouse expressing human MUC1. ConclusionsThe high antitumoral efficacy of 16A-MMAE suggest that aberrant glycosylated MUC1 neoantigen is a target with high positivity in multiple cancer types for ADC development. Personalized therapy may be achieved by development of glycosite-specific antibody-drug conjugates.

pharmacology and toxicology↗

bioRxiv2019

Human condensin I and II drive extensive ATP-dependent compaction of nucleosome-bound DNA

Structural maintenance of chromosomes (SMC) complexes are essential for genome organization from bacteria to humans, but their mechanisms of action remain poorly understood. Here, we characterize human SMC complexes condensin I and II and unveil the architecture of the human condensin II complex, revealing two putative DNA-binding sites. Using single-molecule imaging, we demonstrate that both condensin I and II exhibit ATP-dependent motor activity and promote extensive and reversible compaction of double-stranded DNA. Nucleosomes are incorporated into DNA loops during compaction without being displaced from the DNA, indicating that condensin complexes can readily act upon nucleosome fibers. These observations shed light on critical processes involved in genome organization in human cells.\n\nOne Sentence SummaryATP-dependent DNA compaction by human condensin complexes.

biochemistry↗

bioRxiv2019

A meiosis-specific AAA+ assembly reveals repurposing of ORC during budding yeast gametogenesis

ORC (Orc1-6) is an AAA+ complex that loads the AAA+ MCM helicase to replication origins. Orc1, a subunit of ORC, functionally interacts with budding yeast Pch2, a meiosis-specific AAA+ protein. Pch2 regulates several chromosomal events of gametogenesis, but mechanisms that dictate Pch2 function remain poorly understood. We demonstrate that ORC directly interacts with an AAA+ Pch2 hexamer. The ORC-Pch2 assembly is established without Cdc6, a factor crucial for ORC-MCM binding. Biochemical analysis suggests that Pch2 utilizes ORCs Cdc6-binding interface and employs its non-enzymatic NH2-terminal domain and AAA+ core to engage ORC. In contrast to phenotypes observed upon Orc1 impairment, nuclear depletion of other subunits of ORC does not lead to Pch2-like phenotypes, indicating that ORC integrity per se is not required to support Pch2 function. We thus reveal functional interplay between Pch2 and ORC, and uncover the repurposing of ORC to establish a non-canonical and meiosis-specific AAA+ assembly.

biochemistry↗

bioRxiv2018

Effect of Lactobacillus reuteri on intestinal microflora and immune parameters: involvement of sex differences

Probiotic candidate L. reuteri was screened out for in vivo experiments based on a relatively higher gastrointestinal tolerance and moderate adhesiveness. As results shown in in-vivo experiments, a significantly higher level of IL-12 at low-dose group was found both in females and males. Higher levels of T-lymphocytes were also observed in females compared to control group, however, males displayed a reduction expcept for CD8-positive cells in ileum. In comparison to the control group, the relative abundance of phylotypes in the phylum Bacteroidetes (genus of Bacteroides, Prevotella) and Firmicutes (genus of ClostridiumIV) exihibited a reserve shift between sexes after L. reuteri intervened. Meanwhile, the relative abundance of several taxa (Acetobacteroides, Lactobcaillus, bacillus) also differed markedly in sexes at low-dose group, together with microbiota diversity, as indicated by Shannon index.\n\nImportanceSexual dimorphism has triggered researchers attention. However, the relationship between immune parameters and gut microbiota caused by Lactobacillus at different dosage are not fully elucidated. In present research, the possible probiotic role of L. reuteri DMSZ 8533 on immunomodulation and effect on fecal microbiota composition were investigated. Our findings demonstrate the importance of L. reuteri DMSZ 8533 as a potential probiotic strain with an immunomodulatory effect, which also alters the microflora composition depending on the sex of the host.

microbiology↗

bioRxiv2018

YAP1 Oncogene is a Context-specific Driver for Pancreatic Ductal Adenocarcinoma

AbstractTranscriptomic profiling classifies pancreatic ductal adenocarcinoma (PDAC) into several molecular subtypes with distinctive histological and clinical characteristics. However, little is known about the molecular mechanisms that define each subtype and their correlation with clinical outcome. Mutant KRAS is the most prominent driver in PDAC, present in over 90% of tumors, but the dependence of tumors on oncogenic KRAS signaling varies between subtypes. In particular, squamous subtype are relatively independent of oncogenic KRAS signaling and typically display much more aggressive clinical behavior versus progenitor subtype. Here, we identified that YAP1 activation is enriched in the squamous subtype and associated with poor prognosis. Activation of YAP1 in progenitor subtype cancer cells profoundly enhanced malignant phenotypes and transformed progenitor subtype cells into squamous subtype. Conversely, depletion of YAP1 specifically suppressed tumorigenicity of squamous subtype PDAC cells. Mechanistically, we uncovered a significant positive correlation between WNT5A expression and the YAP1 activity in human PDAC, and demonstrated that WNT5A overexpression led to YAP1 activation and recapitulated YAP1-dependent but Kras-independent phenotype of tumor progression and maintenance. Thus, our study identifies YAP1 oncogene as a major driver of squamous subtype PDAC and uncovers the role of WNT5A in driving PDAC malignancy through activation of the YAP pathway.

cancer biology↗