@article{pmid41162396,

title = {A red fluorescent genetically encoded biosensor for in vivo imaging of extracellular L-lactate dynamics},

author = {Yuki Kamijo and Philipp Mächler and Natalie Ness and Cong Quang Vu and Tsukasa Kusakizako and Jamsad Mannuthodikayil and Zaneta Ku and Marc Boisvert and Ekaterina Grebenik and Ikumi Miyazaki and Rina Hashizume and Haruaki Sato and Rui Liu and Yukiko Hori and Taisuke Tomita and Tetsuro Katayama and Akihiro Furube and Gabriela Caraveo and Marie-Eve Paquet and Mikhail Drobizhev and Osamu Nureki and Satoshi Arai and Marco Brancaccio and Robert E Campbell and David Kleinfeld and Yusuke Nasu},

doi = {10.1038/s41467-025-64484-x},

issn = {2041-1723},

year  = {2025},

date = {2025-10-01},

journal = {Nat Commun},

volume = {16},

number = {1},

pages = {9531},

abstract = {L-Lactate is increasingly recognized as an intercellular energy currency in mammals, but mysteries remain regarding the spatial and temporal dynamics of its release and uptake between cells via the extracellular environment. Here we introduce R-eLACCO2.1, a red fluorescent extracellular L-lactate biosensor that is superior to previously reported green fluorescent biosensors in in vivo sensitivity to increases in extracellular L-lactate and spectral orthogonality. R-eLACCO2.1 exhibits excellent fluorescence response in cultured cells, mouse brain slices, and live mice. R-eLACCO2.1 also serves as an effective fluorescence lifetime-based biosensor. Using R-eLACCO2.1, we monitor whisker stimulation and locomotion-induced changes in endogenous extracellular L-lactate in the somatosensory cortex of awake mice. To highlight the potential insights gained from in vivo measurements with R-eLACCO2.1, we perform dual-color imaging from the somatosensory cortex of actively locomoting mice. This enables us to simultaneously observe the neural activity, reported by a green fluorescent GCaMP calcium ion biosensor, and extracellular L-lactate. As the high-performance tool in the suite of extracellular L-lactate biosensors, R-eLACCO2.1 is ideally suited to delimit the emerging roles of L-lactate in mammalian metabolism.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid40382320,

title = {Targeting C1q prevents microglia-mediated synaptic removal in neuropathic pain},

author = {Noosha Yousefpour and Shannon N Tansley and Samantha Locke and Behrang Sharif and Marc Parisien and Farin B Bourojeni and Haley Deamond and Vidhu Mathur and Nia Rahman-Khan Arana and Jean Sebastien Austin and Valerie Bourassa and Chengyang Wang and Valérie C Cabana and Calvin Wong and Kevin C Lister and Rose Rodrigues and Manon St-Louis and Marie-Eve Paquet and Michael C Carroll and Yaisa Andrews-Zwilling and Philippe Seguela and Artur Kania and Ted Yednock and Jeffrey S Mogil and Yves De Koninck and Luda Diatchenko and Arkady Khoutorsky and Alfredo Ribeiro-da-Silva},

doi = {10.1038/s41467-025-59849-1},

issn = {2041-1723},

year  = {2025},

date = {2025-05-01},

journal = {Nat Commun},

volume = {16},

number = {1},

pages = {4590},

abstract = {Activation of spinal microglia following peripheral nerve injury is a central component of neuropathic pain pathology. While the contributions of microglia-mediated immune and neurotrophic signalling have been well-characterized, the phagocytic and synaptic pruning roles of microglia in neuropathic pain remain less understood. Here, we show that peripheral nerve injury induces microglial engulfment of dorsal horn synapses, leading to a preferential loss of inhibitory synapses and a shift in the balance between inhibitory and excitatory synapse density. This synapse removal is dependent on the microglial complement-mediated synapse pruning pathway, as mice deficient in complement C3 and C4 do not exhibit synapse elimination. Furthermore, pharmacological inhibition of the complement protein C1q prevents dorsal horn inhibitory synapse loss and attenuates neuropathic pain. Therefore, these results demonstrate that the complement pathway promotes persistent pain hypersensitivity via microglia-mediated engulfment of dorsal horn synapses in the spinal cord, revealing C1q as a therapeutic target in neuropathic pain.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid40195305,

title = {Far-red fluorescent genetically encoded calcium ion indicators},

author = {Rochelin Dalangin and Bill Z Jia and Yitong Qi and Abhi Aggarwal and Kenryo Sakoi and Mikhail Drobizhev and Rosana S Molina and Ronak Patel and Ahmed S Abdelfattah and Jihong Zheng and Daniel Reep and Jeremy P Hasseman and  and Yufeng Zhao and Jiahui Wu and Kaspar Podgorski and Alison G Tebo and Eric R Schreiter and Thomas E Hughes and Takuya Terai and Marie-Eve Paquet and Sean G Megason and Adam E Cohen and Yi Shen and Robert E Campbell},

doi = {10.1038/s41467-025-58485-z},

issn = {2041-1723},

year  = {2025},

date = {2025-04-01},

journal = {Nat Commun},

volume = {16},

number = {1},

pages = {3318},

abstract = {Genetically encoded calcium ion (Ca) indicators (GECIs) are widely-used molecular tools for functional imaging of Ca dynamics and neuronal activities with single-cell resolution. Here we report the design and development of two far-red fluorescent GECIs, FR-GECO1a and FR-GECO1c, based on the monomeric far-red fluorescent proteins mKelly1 and mKelly2. FR-GECOs have excitation and emission maxima at ~596 nm and ~644 nm, respectively, display large responses to Ca in vitro (ΔF/F = 6 for FR-GECO1a, 18 for FR-GECO1c), are bright under both one-photon and two-photon illumination, and have high affinities (apparent K = 29 nM for FR-GECO1a, 83 nM for FR-GECO1c) for Ca. FR-GECOs offer sensitive and fast detection of single action potentials in neurons, and enable in vivo all-optical manipulation and measurement of cellular activities in combination with optogenetic actuators.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid39811063,

title = {Multimodal fluorescence-optoacoustic  imaging of the near-infrared calcium ion indicator NIR-GECO2G},

author = {Sarah F Shaykevich and Justin P Little and Yong Qian and Marie-Eve Paquet and Robert E Campbell and Daniel Razansky and Shy Shoham},

doi = {10.1016/j.pacs.2024.100671},

issn = {2213-5979},

year  = {2025},

date = {2025-02-01},

journal = {Photoacoustics},

volume = {41},

pages = {100671},

abstract = {Measuring whole-brain distributed functional activity is an important unmet need in neuroscience, requiring high temporal resolution and cellular specificity across large volumes. Functional optoacoustic neuro-tomography (FONT) with genetically encoded calcium ion indicators is a promising approach towards this goal. However, it has not yet been applied in the near-infrared (NIR) range that provides deep penetration and low vascular background optimal for  neuroimaging. Here, we study the noninvasive multimodal fluorescence and optoacoustic imaging performance of state-of-the-art NIR calcium ion indicator NIR-GECO2G in the mouse brain. We observe robust  signals with widefield fluorescence, and for the first time, with FONT. We also show that in both modalities, the NIR-GECO2G signal improves more than twofold in the biliverdin-enriched   mouse line compared to wild type. Our findings demonstrate the potential of multimodal fluorescence and optoacoustic NIR imaging, opening new possibilities for whole-brain real-time functional imaging in rodents.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid38545127,

title = {Understanding the nervous system: lessons from Frontiers in Neurophotonics},

author = {Yves De Koninck and Johanna Alonso and Stéphane Bancelin and Jean-Claude Béïque and Erik Bélanger and Catherine Bouchard and Marco Canossa and Johan Chaniot and Daniel Choquet and Marie-Ève Crochetière and Nanke Cui and Lydia Danglot and Paul De Koninck and Anna Devor and Mathieu Ducros and Angela M Getz and Mohamed Haouat and Iván Coto Hernández and Nate Jowett and Iason Keramidis and Céline Larivière-Loiselle and Flavie Lavoie-Cardinal and Harold D MacGillavry and Asiye Malkoç and Mattia Mancinelli and Pierre Marquet and Steven Minderler and Maxime Moreaud and U Valentin Nägerl and Katerina Papanikolopoulou and Marie-Eve Paquet and Lorenzo Pavesi and David Perrais and Romain Sansonetti and Martin Thunemann and Beatrice Vignoli and Jenny Yau and Clara Zaccaria},

doi = {10.1117/1.NPh.11.1.014415},

issn = {2329-423X},

year  = {2024},

date = {2024-01-01},

journal = {Neurophotonics},

volume = {11},

number = {1},

pages = {014415},

abstract = {The Frontiers in Neurophotonics Symposium is a biennial event that brings together neurobiologists and physicists/engineers who share interest in the development of leading-edge photonics-based approaches to understand and manipulate the nervous system, from its individual molecular components to complex networks in the intact brain. In this Community paper, we highlight several topics that have been featured at the symposium that took place in October 2022 in Québec City, Canada.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37551444,

title = {Restoring neuronal chloride extrusion reverses cognitive decline linked to Alzheimer's disease mutations},

author = {Iason Keramidis and Brendan B McAllister and Julien Bourbonnais and Feng Wang and Dominique Isabel and Edris Rezaei and Romain Sansonetti and Phil Degagne and Justin P Hamel and Mojtaba Nazari and Samsoon Inayat and Jordan C Dudley and Annie Barbeau and Lionel Froux and Marie-Eve Paquet and Antoine G Godin and Majid H Mohajerani and Yves De Koninck},

doi = {10.1093/brain/awad250},

issn = {1460-2156},

year  = {2023},

date = {2023-12-01},

journal = {Brain},

volume = {146},

number = {12},

pages = {4903--4915},

abstract = {Disinhibition during early stages of Alzheimer's disease is postulated to cause network dysfunction and hyperexcitability leading to cognitive deficits. However, the underlying molecular mechanism remains unknown. Here we show that, in mouse lines carrying Alzheimer's disease-related mutations, a loss of neuronal membrane potassium-chloride cotransporter KCC2, responsible for maintaining the robustness of GABAA-mediated inhibition, occurs pre-symptomatically in the hippocampus and prefrontal cortex. KCC2 downregulation was inversely correlated with the age-dependent increase in amyloid-β 42 (Aβ42). Acute administration of Aβ42 caused a downregulation of membrane KCC2. Loss of KCC2 resulted in impaired chloride homeostasis. Preventing the decrease in KCC2 using long term treatment with CLP290 protected against deterioration of learning and cortical hyperactivity. In addition, restoring KCC2, using short term CLP290 treatment, following the transporter reduction effectively reversed spatial memory deficits and social dysfunction, linking chloride dysregulation with Alzheimer's disease-related cognitive decline. These results reveal KCC2 hypofunction as a viable target for treatment of Alzheimer's disease-related cognitive decline; they confirm target engagement, where the therapeutic intervention takes place, and its effectiveness.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37891202,

title = {Lactate biosensors for spectrally and spatially multiplexed fluorescence imaging},

author = {Yusuke Nasu and Abhi Aggarwal and Giang N T Le and Camilla Trang Vo and Yuki Kambe and Xinxing Wang and Felix R M Beinlich and Ashley Bomin Lee and Tina R Ram and Fangying Wang and Kelsea A Gorzo and Yuki Kamijo and Marc Boisvert and Suguru Nishinami and Genki Kawamura and Takeaki Ozawa and Hirofumi Toda and Grant R Gordon and Shaoyu Ge and Hajime Hirase and Maiken Nedergaard and Marie-Eve Paquet and Mikhail Drobizhev and Kaspar Podgorski and Robert E Campbell},

doi = {10.1038/s41467-023-42230-5},

issn = {2041-1723},

year  = {2023},

date = {2023-10-01},

journal = {Nat Commun},

volume = {14},

number = {1},

pages = {6598},

abstract = {L-Lactate is increasingly appreciated as a key metabolite and signaling molecule in mammals. However, investigations of the inter- and intra-cellular dynamics of L-lactate are currently hampered by the limited selection and performance of L-lactate-specific genetically encoded biosensors. Here we now report a spectrally and functionally orthogonal pair of high-performance genetically encoded biosensors: a green fluorescent extracellular L-lactate biosensor, designated eLACCO2.1, and a red fluorescent intracellular L-lactate biosensor, designated R-iLACCO1. eLACCO2.1 exhibits excellent membrane localization and robust fluorescence response. To the best of our knowledge, R-iLACCO1 and its affinity variants exhibit larger fluorescence responses than any previously reported intracellular L-lactate biosensor. We demonstrate spectrally and spatially multiplexed imaging of L-lactate dynamics by coexpression of eLACCO2.1 and R-iLACCO1 in cultured cells, and in vivo imaging of extracellular and intracellular L-lactate dynamics in mice.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid37817802,

title = {A robust and reliable methodology to perform GECI-based multi-time point neuronal calcium imaging within mixed cultures of human iPSC-derived cortical neurons},

author = {Niraj Patel and Vincent Ouellet and François Paquet-Mercier and Nizar Chetoui and Erik Bélanger and Marie-Eve Paquet and Antoine G Godin and Pierre Marquet},

doi = {10.3389/fnins.2023.1247397},

issn = {1662-4548},

year  = {2023},

date = {2023-01-01},

journal = {Front Neurosci},

volume = {17},

pages = {1247397},

abstract = {INTRODUCTION: Human induced pluripotent stem cells (iPSCs), with their ability to generate human neural cells (astrocytes and neurons) from patients, hold great promise for understanding the pathophysiology of major neuropsychiatric diseases such as schizophrenia and bipolar disorders, which includes alterations in cerebral development. Indeed, the  neurodifferentiation of iPSCs, while recapitulating certain major stages of neurodevelopment , makes it possible to obtain networks of living human neurons. The culture model presented is particularly attractive within this framework since it involves iPSC-derived neural cells, which more specifically differentiate into cortical neurons of diverse types (in particular glutamatergic and GABAergic) and astrocytes. However, these  neuronal networks, which may be heterogeneous in their degree of differentiation, remain challenging to bring to an appropriate level of maturation. It is therefore necessary to develop tools capable of analyzing a large number of cells to assess this maturation process. Calcium (Ca) imaging, which has been extensively developed, undoubtedly offers an incredibly good approach, particularly in its versions using genetically encoded calcium indicators. However, in the context of these iPSC-derived neural cell cultures, there is a lack of studies that propose Ca imaging methods that can finely characterize the evolution of neuronal maturation during the neurodifferentiation process.nnMETHODS: In this study, we propose a robust and reliable method for specifically measuring neuronal activity at two different time points of the neurodifferentiation process in such human neural cultures. To this end, we have developed a specific Ca signal analysis procedure and tested a series of different AAV serotypes to obtain expression levels of GCaMP6f under the control of the neuron-specific human synapsin1 (hSyn) promoter.nnRESULTS: The retro serotype has been found to be the most efficient in driving the expression of the GCaMP6f and is compatible with multi-time point neuronal Ca imaging in our human iPSC-derived neural cultures. An AAV2/retro carrying GCaMP6f under the hSyn promoter (AAV2/retro-hSyn-GCaMP6f) is an efficient vector that we have identified. To establish the method, calcium measurements were carried out at two time points in the neurodifferentiation process with both hSyn and CAG promoters, the latter being known to provide high transient gene expression across various cell types.nnDISCUSSION: Our results stress that this methodology involving AAV2/retro-hSyn-GCaMP6f is suitable for specifically measuring neuronal calcium activities over multiple time points and is compatible with the neurodifferentiation process in our mixed human neural cultures.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid36816616,

title = {Modulating the activity of human nociceptors with a SCN10A promoter-specific viral vector tool},

author = {Stephanie Mouchbahani-Constance and Camille Lagard and Justine Schweizer and Isabelle Labonté and Miltiadis Georgiopoulos and Colombe Otis and Manon St-Louis and Eric Troncy and Philippe Sarret and Alfredo Ribeiro-Da-Silva and Jean A Ouellet and Philippe Séguéla and Marie-Eve Paquet and Reza Sharif-Naeini},

doi = {10.1016/j.ynpai.2023.100120},

issn = {2452-073X},

year  = {2023},

date = {2023-01-01},

journal = {Neurobiol Pain},

volume = {13},

pages = {100120},

abstract = {Despite the high prevalence of chronic pain as a disease in our society, there is a lack of effective treatment options for patients living with this condition. Gene therapies using recombinant AAVs are a direct method to selectively express genes of interest in target cells with the potential of, in the case of nociceptors, reducing neuronal firing in pain conditions. We designed a recombinant AAV vector expressing cargos whose expression was driven by a portion of the SCN10A (Na1.8) promoter, which is predominantly active in nociceptors. We validated its specificity for nociceptors in mouse and human dorsal root ganglia and showed that it can drive the expression of functional proteins. Our viral vector and promoter package drove the expression of both excitatory or inhibitory DREADDs in primary human DRG cultures and in whole cell electrophysiology experiments, increased or decreased neuronal firing, respectively. Taken together, we present a novel viral tool that drives expression of cargo specifically in human nociceptors. This will allow for future specific studies of human nociceptor properties as well as pave the way for potential future gene therapies for chronic pain.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}