Biology subjects

Wong, K. C.

Publications and source records attributed to Wong, K. C..

4 recordsLinked to original sources

bioRxiv2025

Molecular biointerface characterisation for an implanted medical device using cryogenic orbitrap secondary ion mass spectrometry (Cryo-OrbiSIMS)

Implanted medical devices often fail due to foreign body reaction (FBR), a process still not fully understood. This work presents a new depth profiling approach to provide insight into the spatial metabolomics of the biointerface of implants, revealing biomolecular strata representative of the host response. This study examines silicone rubber poly(dimethyl siloxane) catheters implanted in mice for 1 and 28 days. Cryo-OrbiSIMS was used in combination with ToF-SIMS to identify metabolite profiles from the biological deposit found on the implants after removal from the tissue which were previously unattainable using tissue sectioning. Machine learning and statistical analysis of the profiles were used to help identify early biointerface responses to the implant, including at 1 day of implantation the observation of elevated sugars and itaconate an immunomodulatory metabolite that modulates FBR. At day 28 inflammation associated markers were observed such as urate and palmitic acid (FA 16:0). Depth profiling revealed two distinct molecular layers in the deposits: amino acids, and nucleic acids were preferentially seen towards the host tissue, consistent with the observation of a cell monolayer in the tissue sections, whereas certain lipids and fatty acids where either at the catheter-deposit interface or towards the host tissue after 28 days. The stratification was less well developed at 1-day implantation, but common lipids were seen at the deposit-implant interface across both time points. These insights advance understanding of FBR and support the development of improved implant materials.

bioinformatics↗

bioRxiv2024

Peptidergic neurons with extensive branching orchestrate the internal states and energy balance of male Drosophila melanogaster.

Neuropeptide SIFamide (SIFa) neurons in Drosophila melanogaster have been characterized by their exceptionally elaborate arborization patterns, which extend from the brain into the ventral nerve cord (VNC). SIFa neurons are equipped to receive signals that integrate both internal physiological cues and external environmental stimuli. These signals enable the neurons to regulate energy balance, sleep patterns, metabolic status, and circadian timing. These peptidergic neurons are instrumental in orchestrating the animals internal states and refining its behavioral responses, yet the precise molecular underpinnings of this process remain elusive. Here we demonstrate that SIFa neurons coordinate a range of behavioral responses by selectively integrating inputs and outputs in a context-dependent manner. These neurons engage in a feedback loop with sNPF neurons in the ventral nerve cord, modifying behaviors such as long mating duration (LMD) and shorter mating duration (SMD). Furthermore, SIFa neurons receive essential inputs from neuropeptides Dsk, sNPF, and dilp2, which regulate interval timing behaviors. Activating SIFa neurons leads to reduced mating duration and increased food intake, while deactivating them reduces food intake. Overall, these findings demonstrate the importance of SIFa neurons in absorbing inputs and turning them into behavioral outputs, shedding light on animals intricate behavioral orchestration.

neuroscience↗

bioRxiv2024

Long-range neuropeptide relay as a central-peripheral communication mechanism for the context-dependent modulation of interval timing behaviors.

Neuropeptides play crucial roles in regulating context-dependent behaviors, but the underlying mechanisms remain elusive. We investigate the role of the neuropeptide SIFa and its receptor SIFaR in regulating two distinct mating duration behaviors in male Drosophila: Longer-Mating-Duration (LMD) and Shorter-Mating-Duration (SMD). We found that SIFaR expression in specific neurons is required for both LMD and SMD behaviors. Social context and sexual experience lead to synaptic reorganization between SIFa and SIFaR neurons, altering internal states of brain. We revealed that the SIFa-SIFaR/Crz-CrzR neuropeptide relay pathway is essential for generating distinct interval timing behaviors, with Crz neurons being responsive to the activity of SIFa neurons. Additionally, CrzR expression in non-neuronal cells is critical for regulating LMD and SMD behaviors. Our study provides insights into how neuropeptides and their receptors modulate context-dependent behaviors through synaptic plasticity and calcium signaling, with implications for understanding the neural circuitry underlying interval timing and neuropeptidergic system modulation of behavioral adaptations.

neuroscience↗

bioRxiv2019

Neuropeptide relay between SIFa signaling controls the experience-dependent mating duration of male Drosophila

Drosophila melanogaster is a suitable model for investigating how neuropeptides influence animal behaviours and physiology. We previously reported that two behavioural paradigms control mating duration of male Drosophila, called Longer-Mating-Duration (LMD) and Shorter-Mating-Duration (SMD) that are induced through socio-sexual environment prior to copulation. Understanding the molecular and cellular mechanisms by which males exhibit plasticity to different social cues remains poorly understood. Here, we show that SIFa modulates the neural circuitry for both LMD and SMD. Neuropeptide-to-neuropeptide communication, so called neuropeptide relay plays a key role to mediate this control. We identified that 7 neuropeptides expressed in SIFa Receptor-positive cells are functionally important to regulate either LMD and/or SMD. The modulation of two independent mating duration behaviour by the different SIFa-mediated neuropeptide relay will help to further investigate how the neuropeptidergic modulation can control complex behaviours.

animal behavior and cognition↗