Biology subjects

Tsao, J.

Publications and source records attributed to Tsao, J..

3 recordsLinked to original sources

bioRxiv2023

Differentiation state and culture conditions impact neural stem/progenitor cell-derived extracellular vesicle bioactivity

Extracellular vesicles (EVs) derived from neural progenitor/stem cells (NPSCs) have shown promising efficacy in a variety of preclinical models. However, NPSCs lack critical neuroregenerative functionality such as myelinating capacity. Further, culture conditions used in NPSC EV production lack standardization and identification of optimal conditions for NPSC EV neurogenic bioactivity. Here, we assessed whether further differentiated oligodendrocyte precursor cells (OPCs) and immature oligodendrocytes (iOLs) that give rise to mature myelinating oligodendrocytes could yield EVs with neurotherapeutic properties comparable or superior to those from NPSCs as well as mesenchymal stromal cells (MSCs), as MSC EVs are also commonly reported to have neurotherapeutic activity. We additionally examined the effects of four different extracellular matrix (ECM) coating materials (laminin, fibronectin, Matrigel, and collagen IV) and the presence or absence of growth factors (EGF, bFGF, and NGF) in cell culture on the ultimate properties of EVs. The data show that OPC EVs and iOL EVs performed similarly to NPSC EVs in PC-12 proliferation and RAW264.7 mouse macrophage antiinflammatory assays, but NPSC EVs performed better in a PC-12 neurite outgrowth assay. Additionally, the presence of nerve growth factor (NGF) in culture was found to be maximize NPSC EV bioactivity among the conditions tested. NPSC EVs produced under rationally-selected culture conditions (fibronectin + NGF) enhanced axonal regeneration and muscle reinnervation in a rat nerve crush injury model. These results highlight the impact of culture conditions on NPSC EV neuroregenerative bioactivity, thus providing additional rationale for standardization and optimization of culture conditions for NPSC EV production. Table of Contents O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=35 SRC="FIGDIR/small/528366v1_ufig1.gif" ALT="Figure 1"> View larger version (13K): org.highwire.dtl.DTLVardef@447d23org.highwire.dtl.DTLVardef@73a5cborg.highwire.dtl.DTLVardef@89dbb0org.highwire.dtl.DTLVardef@b62d39_HPS_FORMAT_FIGEXP M_FIG C_FIG Extracellular vesicles (EVs) purified from neural progenitor/stem cells (NPSCs) have been investigated for neurotherapeutic activity, however significant variability in culture conditions limits reproducibility and efficacy of this approach. Here, we examined the impact of extracellular matrix (ECM) components and growth factors in NPSC culture on the bioactivity on the bioactivity of their EVs. The results show that EVs from NPSCs cultured with a rationally-selected ECM type (fibronectin) and growth factor (nerve growth factor (NGF)) enhanced nerve regeneration and muscle recovery in a rat sciatic nerve crush injury model.

bioengineering↗

bioRxiv2022

Atomic model of Vesicular Stomatitis Virus and Mechanism of Assembly

Like other negative-strand RNA viruses (NSVs) such as influenza and rabies, vesicular stomatitis virus (VSV) has a three-layered organization: a layer of matrix protein (M) resides between the membrane envelope, studded by glycoprotein (G), and the nucleocapsid, composed of the nucleocapsid protein (N) and the encapsidated genomic RNA. Lack of in situ atomic structures of these viral components has limited our understanding of the virion assembly mechanism. Here, by cryoEM and sub-particle reconstruction, we have determined the in situ structures of M and N inside VSV at 3.47 [A] resolution. In the virion, N and M have a stoichiometry of 1:2. The in situ structures of both N and M differ from their crystal structures in their N-terminal segments and oligomerization loops. N-RNA, N-N, and N-M-M interactions govern the formation of the capsid. A double layer of M contributes to packaging of the helical nucleocapsid: the inner M (IM) joins neighboring turns of the N helix, while the outer M (OM) contacts G and the membrane envelope. The pseudo-crystalline organization of G is further mapped by cryoET. The mechanism of VSV assembly is delineated by the network interactions of these viral components.

biochemistry↗

bioRxiv2022

Northward Expansion of Amblyomma americanum (Acari: Ixodidae) into Southern Michigan

Amblyomma americanum (Linnaeus) (Acari: Ixodidae) (lone star tick) is an aggressive, generalist parasite that vectors numerous important human and animal pathogens. In recent decades its geographic range has expanded northwards from endemic regions in the southeastern and southcentral US. In 2019 five questing A. americanum comprising two life stages were detected at one site in Berrien County, in southwestern Michigan, satisfying one CDC criterium for an established population for the first time in the state. To better characterize the northern extent of emerging A. americanum, we conducted active surveillance (i.e., drag sampling) in summer 2020 throughout Michigans southern counties and detected one adult A. americanum from each of six widespread sites, including where they had been detected in 2019. A larger established population was identified at another site in Berrien County, which yielded 691 A. americanum comprising three life stages. Questing tick phenologies at this site were similar to that reported for other regions. Statewide surveillance in 2021 revealed no A. americanum outside of Berrien County, but establishment criteria were met again at the two sites where established populations were first detected respectively in 2019 and 2020. These observations may represent the initial successful invasion of A. americanum into Michigan. Data from passive (1999-2020) and active surveillance (2004-2021) efforts, including a domestic animal sentinel program (2015-2018), are reported to provide context for this nascent invasion. Continued active surveillance is needed to help inform the public, medical professionals, and public health officials of the health risks associated with this vector.

ecology↗