Biology subjects

Cheng, Y.-J.

Publications and source records attributed to Cheng, Y.-J..

3 recordsLinked to original sources

bioRxiv2023

Reliability of dynamic causal modelling of resting state magnetoencephalography

This study assesses the reliability of resting-state dynamic causal modelling (DCM) of magneto-electroencephalography under conductance-based canonical microcircuit models, in terms of both posterior parameter estimates and model evidence. We use resting state magneto-electroencephalography (MEG) data from two sessions, acquired two weeks apart, from a cohort with high between-subject variance arising from Alzheimers disease. Our focus is not on the effect of disease, but on the predictive validity of the methods implicit in their reliability, which is crucial for future studies of disease progression and drug intervention. To assess the predictive validity of first-level DCMs, we compare model evidence associated with the covariance among subject-specific free energies (i.e., the quality of the models) with vs. without interclass correlations. We then used parametric empirical Bayes (PEB) to investigate the predictive validity of DCM parameters at the between subject level. Specifically, we examined the evidence for or against parameter differences (i) within-subject, within-session, between-epochs; (ii) within-subject between-session and (iii) within-site between-subjects, accommodating the conditional dependency among parameter estimates. We show that for data acquired close in time, and under similar circumstances, more than 95% of inferred DCM parameters are unlikely to differ, speaking to mutual predictability over sessions. Using PEB, we show a reciprocal relationship between a conventional definition of reliability and the conditional dependency among inferred model parameters. Our analyses confirm the predictive validity and reliability of the conductance-based DCMs for resting-state neurophysiological data. In this respect, the implicit generative modelling is suitable for interventional and longitudinal studies of neurological and psychiatric disorders. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=147 SRC="FIGDIR/small/562379v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@135c964org.highwire.dtl.DTLVardef@38e4a7org.highwire.dtl.DTLVardef@12bc358org.highwire.dtl.DTLVardef@25f110_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2019

Glia-derived exosomal miR-274 targets Sprouty in trachea and synaptic boutons to modulate growth and responses to hypoxia

Secreted exosomal miRNAs mediate inter-organ/tissue communication by downregulating gene expression, thereby modulating developmental and physiological functions. However, the source, route, and function have not been formally established for specific miRNAs. Here, we show that glial miR-274 non-cell autonomously modulates the growth of synaptic boutons and tracheal branches. Whereas precursor miR-274 was expressed in glia, mature miR-274 was secreted. miR-274 secretion to circulating hemolymph was detected in exosomes, a process requiring ESCRT components in exosome biogenesis and Rab11 and Syx1A in exosome release. miR-274 downregulated Sprouty to activate MAPK in synaptic boutons and tracheal branches, thereby promoting their growth. Expression of miR-274 solely in glia of a mir-274 null mutant reset normal levels of Sprouty and MAPK, and hemolymphatic exosomal miR-274. mir-274 mutant larvae were hypersensitive to hypoxia, which was suppressed by increasing tracheal branches. Thus, glia-derived miR-274 coordinates growth of synaptic boutons and tracheal branches to modulate larval hypoxia responses.

developmental biology↗

bioRxiv2018

Low Level LASER Therapy Induces Therapeutic Angiogenesis in Diabetic Mice with Hindlimb Ischemia

Patients with diabetes mellitus (DM) are at high risk of developing peripheral arterial obstructive disease (PAOD) in lower extremities. Previous studies show low level LASER therapy (LLLT) can increase angiogenesis in vivo and in vitro. Here we performed hindlimb ischemia as PAOD model on diabetic mice to test the effects of LLLT. Twenty C57Bl/6 mice were randomly divided into four groups. Control group mice received femoral artery ligation/excision only. DM group mice were injected with Streptozocin (STZ) to induce diabetes followed by femoral artery ligation/excision. LLLT group mice received femoral artery ligation/excision and the lower limbs received LASER treatment for five days (660nm, 10 min, 1.91 J/cm2) started from second day postoperatively. DM+LLLT group mice were received femoral artery ligation/excision and LASER treatment after diabetes induced. Three days after LASER treatment finished, limb blood flow was measured by Laser Doppler perfusion imaging. Capillary density was assessed by immunofluorescence staining. CD31, VEGF, HIF-1, phospho-ERK, iNOS and eNOS protein level was examined by Western blot. Blood perfusion, capillary density, CD31, and VEGF protein levels were significantly higher in those groups received LLLT compared to control and DM group. Low level LASER significantly increased ERK phosphorylation and HIF-1 expression. In addition, phospho-eNOS was increased but iNOS protein level was decreased in mice received LASER treatment. In summary, the ability of low level LASER to induce therapeutic angiogenesis in diabetic mice suggested this approach deserves investigation as a novel approach to treat PAOD patients.

physiology↗