The long-term goal of the Glykys Laboratory is to identify novel strategies to treat seizures and cytotoxic edema, especially in neonates. 

To reach this goal, we are addressing the following themes:

  1. The workings of the brain's inhibitory system at the cellular and network level.
  2. Movement of water and ions move in and out of neurons.
  3. Neuronal injury pathways after hypoxia, excitotoxic injury, and seizures. 

Research areas of the lab include:

  1. Changes in neuronal chloride, calcium, and cellular volume during pathological conditions.
  2. Neonatal seizures and epilepsy.
  3. GABAA receptor physiology.

We approach these research areas with electrophysiological and two-photon imaging techniques in the neocortex. We complement these approaches with immunohistochemistry. 


Learn more by checking these recent publications:

 

Liddiard GT, Suryahvanshi PS, Glykys J. Enhancing GABAergic tonic inhibition reduces seizure-like activity in the neonatal mouse hippocampus and neocortex. Journal of Neuroscience 4 January 2024, e1342232023; DOI: https://doi.org/10.1523/JNEUROSCI.1342-23.2023

  • Around 30-50% of neonatal seizures resist current treatments.

  • Whether enhancing tonic inhibition decreases seizure-like activity in the neonate when GABA is mainly depolarizing at this age is unknown. 

  • We showed that THIP, a δ-subunit-selective GABAA receptor agonist, enhanced GABAergic tonic inhibitory conductances in layer V neocortical and CA1 pyramidal neurons and increased their rheobase without altering sEPSCs characteristics.

  • Two-photon calcium imaging demonstrated that enhancing the activity of extrasynaptic GABAARs decreased neuronal firing in both brain regions.

  • In in vitro seizure models, THIP reduced epileptiform activity in the neocortex and CA1 hippocampal region of neonatal and adult brain slices in a dose-dependent manner.

  • Our results suggest that augmenting tonic inhibition could be an alternative treatment for neonatal seizures, especially in pharmacy-resistant ones.


     
THIP on neonatal seizures
Enhancing tonic inhibitory currents reduces seizure-like events in the neonatal neocortex and CA1 region in the Low-Mg2+ model of pharmacoresistant seizures. (A and B) Top: Seizure-like events (SLEs) induced by Low-Mg2+ aCSF in the neocortex, layer IV/V (A) and CA1 region (stratum pyramidale) (B) recorded with an extracellular field electrode in acute brain slices (P8). Middle: Magnification. Bottom: Fast Fourier Transform (FFT) power area. (C) FFT power area during baseline, THIP, and wash-out conditions in the neonatal neocortex (left) and CA1 region (right). (D) Ratio change in SLE with THIP. (E) Number of SLEs during baseline, THIP perfusion, and wash-out.

Islam MS, Suryavanshi P, Baule SM, Glykys J*, Baek S*. A Deep Learning Approach for Neuronal Cell Body Segmentation in Neurons Expressing GCaMP using a Swin Transformer. eNeuro. 2023 Sep 13; ENEURO.0148-23.2023. PMID: 37704367. [*, Corresponding authors]

  • Neuronal segmentation is challenging due to the complex morphological structures of neuronal cell bodies and their surroundings.

  •  We developed a deep-learning-based approach for automated, fast, robust 2D neuronal cell body segmentation of neurons expressing fluorescent markers using a state-of-the-art vision transformer (Swin transformer).

  • This approach for neuronal cell body segmentation can assist researchers in evaluating the changes in neuronal cell body sizes under different pathological conditions.


     
Swin transformer
The architecture of the deep neural network is based on the Swin transformer (Lin et al., 2021). The orange outlines represent the output neuronal boundaries identified by the Swin transformer. Scale bar=50 μm.

Suryavanshi P, Langton R, Fairhead K, Glykys J. Brief excitotoxic insults cause a calpain-mediated increase in nuclear membrane permeability in neonatal neurons. bioRxiv. 2023, Aug 23;2023.08.22.554167. doi: 10.1101/2023.08.22.554167

  • We showed rapid nuclear translocation of a genetically encoded calcium sensor (GCaMP6s) a few minutes after different and common brain insults in neonatal neurons using in and ex-vivo multiphoton imaging.

  • We demonstrate that various brief brain insults that model hypoxic events, seizures, and brief NMDA receptor activation enlarge nuclear pores through a calpain-mediated mechanism.

  • The enlargement of the nuclear pores caused large proteins like GCaMP6s to lose their subcellular localization and disrupt nuclear function.

  • This mechanism may underlie neuronal injury in the neonatal period. 

Nuclear pore enlargement
Graphical abstract. Different forms of neuronal insults lead to abnormal translocation of a calcium sensor to the nucleus through a calpaan-mediated mechanism.

Takezawa Y, Langton R, Baule SM, Zimmerman MB, Baek J. Glykys, J. Role of NKCC1 and KCC2 during hypoxia-induced neuronal swelling in the neonatal neocortex. Neurobiol. Dis. 2023. Mar;178:106013. PMID: 36706928

  • We used two-photon laser scanning microscopy to image neurons expressing a genetically encoded fluorescent protein sensitive to chloride concentrations.

  • We analyzed the neurons using a convolutional neural network.  

  • We demonstrated that cation-chloride cotransporters (CCCs) contribute to water movement in neocortical neurons during oxygen-glucose deprivation (OGD) in the neonatal period.

  • Blocking NKCC1, a type of cation-chloride cotransporter, decreased neuronal swelling during early OGD.
  • Furosemide, a diuretic, decreased neuronal swelling during early and prolonged OGD through additional pathways besides CCCs.
  • We conclude that CCCs and other non-CCCs contribute to water movement in neocortical neurons during OGD in the neonatal period.
Role of CCC in neuronal swelling
Graphical abstract. OGD: Oxygen-glucose deprivation, an in vivo model of hypoxia. 

Langton R, Sharma S, Tiarks GC, Bassuk AG, Glykys, J. Lacosamide decreases neonatal seizures without increasing apoptosis. Epilepsia. 2022. Dec;63(12):3051-3065. PMID: 36168798

  • This paper showed that the antiseizure medication lacosamide decreased epileptiform activity in neonates in vitro (Aand behavior seizures in vivo. 
  • Significantly, lacosamide did not increase neuronal apoptosis acutely in vitro or in vivo (B, C). 
lacosamide in neonates
Effect of lacosamide on seizure-like events and apoptosis. (A) Lacosamide decreases seizure-like events in acute neonatal brain slices.  (B) The number of apoptotic neurons does not increase with lacosamide in vivo. CC3: cleaved-caspase 3 (a marker of apoptosis), KA: kainic acid (a drug to induce seizure), LCM: lacosamide.

Tong L, Langton R, Glykys J, Baek S. ANMAF: An automated neuronal morphology analysis framework using convolutional neural networks. Scientific Reports. 2021 April 14;11(1):8179. PMID: 33854113

  • We developed a novel high-throughput neuronal morphology analysis framework (ANMAF), using convolutional neural networks (CNN) to automatically contour the somatic area of fluorescent neurons in acute brain slices.
  • ANMAF produced consistent neuronal contours compared to humans, who exhibited significant variability in repeated measurements.
  • ANMAF was generalizable across different imaging protocols and trainable even with a small number of humanly labeled neurons. 
  • Our framework can facilitate more rigorous and quantitative studies of neuronal morphology by enabling the segmentation of many fluorescent neurons in thick brain slices in a standardized manner.
ANMAF
ANMAF development. (A) Background tiles constructed from multiple two-photon images. (B) Background tiles were shuffled and arbitrarily placed to produce synthetic backgrounds. (C,D) Somatic areas from the original human detected neurons were cut, pasted, and blended into randomly selected backgrounds. (E) The Mask R-CNN model was initiated with parameters transferred from a pre-trained model and fine-tuned with synthetic images. Once trained, ANMAF generated somatic contours from a given neuronal input.