Kv1.3 Channel Up-Regulation in Peripheral Blood T Lymphocytes of Patients With Multiple Sclerosis

Blocking hippocampal voltage-gated potassium channel Kv1.3 by dalfampridine abrogates cognitive impairment in experimental autoimmune encephalomyelitis mouse model

Multiple sclerosis (MS) is devastating motor disorders accompanied by cognitive impairments. Dalfampridine (Dal), was approved for treating MS via blocking voltage-gated potassium channel (Kv). Kv1.3 is one of Dals' targets that showed insults to cognitive function in preclinical and clinical cases. Yet, there is no study that has assessed the potentiality of Dal on Kv1.3-induced cognitive impairment in MS. Thus, the aim of the present study is to reveal the procognitive influence of Dal in the MS animal model. Mice were randomly assigned into four groups. Saline was administered to group 1, conversely groups 2, 3, and 4 received 2 shots of rat spinal cord emulsified with complete Freund's adjuvant. Group 3 received Dal (10 μg/mouse; p. o), while group 4 received Wortmannin (0.1 μg/mouse; i. c.v), a selective phosphoinositide 3-kinases (PI3K) inhibitor, before Dal administration. After 14 days, Dal alleviated motor deficits in the open field arena and rotarod with cognitive restoration in the novel object recognition task. These were accompanied by the reversal of hippocampal neuronal loss and demyelination in corpus callosum. Additionally, Dal inhibited Kv1.3 that enhanced survival signaling, viz; PI3K/Akt. Such activation abates neuroinflammatory markers, glycogen synthase kinase-3 beta (GSK-3β) and nuclear factor-κB levels with subsequent enhancement of BDNF. All these amendments were reversed by Wortmannin pre-administration. In conclusion, this study declares that blockade of Kv1.3 and modulation of PI3K/Akt/GSK-3β/BDNF axis with Dal could be proposed as a promising neuroprotective and memory-enhancing treatment in MS.

Noninvasive Imaging of Immune Cell Activity in Myocardial Infarction Phases Using 99mTc-HYNIC-mAbKv1.3 SPECT/CT

Acute myocardial infarction (MI) remains a leading cause of mortality worldwide, with inflammatory and reparative phases playing critical roles in disease progression. Currently, there is a pressing need for in vivo imaging techniques to monitor immune cell infiltration and inflammation activity during these phases. We developed a novel probe, 99mTc-HYNIC-mAbKv1.3, utilizing a monoclonal antibody that targets the voltage-gated potassium channel 1.3 (Kv1.3). This probe enables in vivo visualization of immune cells that express high levels of Kv1.3 proteins. In a murine MI model, SPECT/CT imaging with 99mTc-HYNIC-mAbKv1.3 demonstrated specific uptake in an infarcted myocardium during the inflammatory phase, reflecting immune cell infiltration and activity. During the reparative phase, the probe exhibited prolonged retention in the infarcted area, suggestive of ongoing immune cell proliferation. Immunofluorescence staining confirmed the probe's specificity. Biodistribution analysis indicated preferential accumulation in the infarcted myocardium and liver, consistent with SPECT/CT findings. Combined with [18F]FDG PET/CT, these modalities provided comprehensive insights into myocardial viability and inflammation. This study highlights the potential of 99mTc-HYNIC-mAbKv1.3 SPECT/CT as a noninvasive tool to monitor immune cell activity in different phases of MI, guide therapeutic interventions, and predict disease progression. Further translational studies are warranted to explore its clinical applicability in cardiac pathologies.

Characterization and modulation of voltage-gated potassium channels in human lymphocytes in schizophrenia

BACKGROUND

It is known that the immune system is dysregulated in schizophrenia, having a state similar to chronic neuroinflammation. The origin of this process is unknown, but it is known that T and B lymphocytes, which are components of the adaptive immune system, play an important role in the pathogenic mechanisms of schizophrenia.

METHODS

We analysed the membrane of PBMCs from patients diagnosed with schizophrenia through proteomic analysis (n = 5 schizophrenia and n = 5 control). We found the presence of the Kv1.3 voltage-gated potassium channel and its auxiliary subunit β1 (KCNAB1) and β2 (KCNAB2). From a sample of 90 participants, we carried out a study on lymphocytes with whole-cell patch-clamp experiments (n = 7 schizophrenia and n = 5 control), western blot (n = 40 schizophrenia and n = 40 control) and confocal microscopy to evaluate the presence and function of different channels. Kv in both cells.

RESULTS

We demonstrated the overexpression of Kv1.1, Kv1.2, Kv1.3, Kv1.6, Kv4.2, Kv4.3 and Kv7.2 channels in PBMCs from patients with schizophrenia. This study represents a groundbreaking exploration, as it involves an electrophysiological analysis performed on T and B lymphocytes from patients diagnosed of schizophrenia compared to healthy participants. We observed that B lymphocytes exhibited an increase in output current along with greater peak current amplitude and voltage conductance curves among patients with schizophrenia compared with healthy controls.

CONCLUSIONS

This study showed the importance of the B lymphocyte in schizophrenia. We know that the immune system is altered in schizophrenia, but the physiological mechanisms of this system are not very well known. We suggest that the B lymphocyte may be relevant in the pathophysiology of schizophrenia and that it should be investigated in more depth, opening a new field of knowledge and possibilities for new treatments combining antipsychotics and immunomodulators. The limitation is that all participants received antipsychotic medication, which may have influenced the differences observed between patients and controls. This implies that more studies need to be done where the groups can be separated according to the antipsychotic drug.

Regulation of T Lymphocyte Functions through Calcium Signaling Modulation by Nootkatone

Recent advancements in understanding the intricate molecular mechanisms underlying immunological responses have underscored the critical involvement of ion channels in regulating calcium influx, particularly in inflammation. Nootkatone, a natural sesquiterpenoid found in Alpinia oxyphylla and various citrus species, has gained attention for its diverse pharmacological properties, including anti-inflammatory effects. This study aimed to elucidate the potential of nootkatone in modulating ion channels associated with calcium signaling, particularly CRAC, KV1.3, and KCa3.1 channels, which play pivotal roles in immune cell activation and proliferation. Using electrophysiological techniques, we demonstrated the inhibitory effects of nootkatone on CRAC, KV1.3, and KCa3.1 channels in HEK293T cells overexpressing respective channel proteins. Nootkatone exhibited dose-dependent inhibition of channel currents, with IC50 values determined for each channel. Nootkatone treatment did not significantly affect cell viability, indicating its potential safety for therapeutic applications. Furthermore, we observed that nootkatone treatment attenuated calcium influx through activated CRAC channels and showed anti-proliferative effects, suggesting its role in regulating inflammatory T cell activation. These findings highlight the potential of nootkatone as a natural compound for modulating calcium signaling pathways by targeting related key ion channels and it holds promise as a novel therapeutic agent for inflammatory disorders.

De novo variants in KCNA3 cause developmental and epileptic encephalopathy

OBJECTIVE

Variants in several potassium channel genes, including KCNA1 and KCNA2, cause Developmental and Epileptic Encephalopathies (DEEs). We investigated whether variants in KCNA3, another mammalian homologue of the Drosophila shaker family and encoding for Kv1.3 subunits, can cause DEE.

METHODS

Genetic analysis of study individuals was performed by routine exome or genome sequencing, usually of parent-offspring trios. Phenotyping was performed via a standard clinical questionnaire. Currents from wild-type and/or mutant Kv1.3 subunits were investigated by whole-cell patch-clamp upon their heterologous expression.

RESULTS

Fourteen individuals, each carrying a de novo heterozygous missense variant in KCNA3, were identified. Most (12/14; 86%) had DEE with marked speech delay with or without motor delay, intellectual disability, epilepsy, and autism spectrum disorder. Functional analysis of Kv1.3 channels carrying each variant revealed heterogeneous functional changes, ranging from "pure" loss-of-function (LoF) effects due to faster inactivation kinetics, depolarized voltage-dependence of activation, slower activation kinetics, increased current inactivation, reduced or absent currents with or without dominant-negative effects, to "mixed" loss- and gain-of-function (GoF) effects. Compared to controls, Kv1.3 currents in lymphoblasts from 1 of the proband displayed functional changes similar to those observed upon heterologous expression of channels carrying the same variant. The antidepressant drug fluoxetine inhibited with similar potency the currents from wild-type and 1 of the Kv1.3 GoF variant.

INTERPRETATION

We describe a novel association of de novo missense variants in KCNA3 with a human DEE, and provide evidence that fluoxetine might represent a potential targeted treatment for individuals carrying variants with significant GoF effects. ANN NEUROL 2024;95:365-376.

Kv1.3 in the spotlight for treating immune diseases

INTRODUCTION

Kv1.3 is the main voltage-gated potassium channel of leukocytes from both the innate and adaptive immune systems. Channel function is required for common processes such as Ca2+ signaling but also for cell-specific events. In this context, alterations in Kv1.3 are associated with multiple immune disorders. Excessive channel activity correlates with numerous autoimmune diseases, while reduced currents result in increased cancer prevalence and immunodeficiencies.

AREAS COVERED

This review offers a general view of the role of Kv1.3 in every type of leukocyte. Moreover, diseases stemming from dysregulations of the channel are detailed, as well as current advances in their therapeutic research.

EXPERT OPINION

Kv1.3 arises as a potential immune target in a variety of diseases. Several lines of research focused on channel modulation have yielded positive results. However, among the great variety of specific channel blockers, only one has reached clinical trials. Future investigations should focus on developing simpler administration routes for channel inhibitors to facilitate their entrance into clinical trials. Prospective Kv1.3-based treatments will ensure powerful therapies while minimizing undesired side effects.

The role of ion channels in T cell function and disease

T lymphocytes (T cells) are an important sub-group of cells in our immune system responsible for cell-mediated adaptive responses and maintaining immune homeostasis. Abnormalities in T cell function, lead the way to the persistence of infection, impaired immunosurveillance, lack of suppression of cancer growth, and autoimmune diseases. Ion channels play a critical role in the regulation of T cell signaling and cellular function and are often overlooked and understudied. Little is known about the ion "channelome" and the interaction of ion channels in immune cells. This review aims to summarize the published data on the impact of ion channels on T cell function and disease. The importance of ion channels in health and disease plus the fact they are easily accessible by virtue of being expressed on the surface of plasma membranes makes them excellent drug targets.