Obesity is an epidemic, calling for innovative and reliable pharmacological strategies. Here, we show that ShK-186, a selective and potent blocker of the voltage-gated Kv1.3 channel, counteracts the ...negative effects of increased caloric intake in mice fed a diet rich in fat and fructose. ShK-186 reduced weight gain, adiposity, and fatty liver; decreased blood levels of cholesterol, sugar, HbA1c, insulin, and leptin; and enhanced peripheral insulin sensitivity. These changes mimic the effects of Kv1.3 gene deletion. ShK-186 did not alter weight gain in mice on a chow diet, suggesting that the obesity-inducing diet enhances sensitivity to Kv1.3 blockade. Several mechanisms may contribute to the therapeutic benefits of ShK-186. ShK-186 therapy activated brown adipose tissue as evidenced by a doubling of glucose uptake, and increased β-oxidation of fatty acids, glycolysis, fatty acid synthesis, and uncoupling protein 1 expression. Activation of brown adipose tissue manifested as augmented oxygen consumption and energy expenditure, with no change in caloric intake, locomotor activity, or thyroid hormone levels. The obesity diet induced Kv1.3 expression in the liver, and ShK-186 caused profound alterations in energy and lipid metabolism in the liver. This action on the liver may underlie the differential effectiveness of ShK-186 in mice fed a chow vs. an obesity diet. Our results highlight the potential use of Kv1.3 blockers for the treatment of obesity and insulin resistance.
Dry eye disease is a very common condition that causes morbidity and healthcare burden and decreases the quality of life. There is a need for a suitable dry eye animal model to test novel ...therapeutics to treat autoimmune dry eye conditions. This protocol describes a chronic autoimmune dry eye rat model. Lewis rats were immunized with an emulsion containing lacrimal gland extract, ovalbumin, and complete Freund's adjuvant. A second immunization with the same antigens in incomplete Freund's adjuvant was administered two weeks later. These immunizations were administered subcutaneously at the base of the tail. To boost the immune response at the ocular surface and lacrimal glands, lacrimal gland extract and ovalbumin were injected into the forniceal subconjunctiva and lacrimal glands 6 weeks after the first immunization. The rats developed dry eye features, including reduced tear production, decreased tear stability, and increased corneal damage. Immune profiling by flow cytometry showed a preponderance of CD3
effector memory T cells in the eyeball.
Voltage-gated sodium (Na V) and potassium (K V) channels are critical components of neuronal action potential generation and propagation. Here, we report that Na Vβ1 encoded by SCN1b , an integral ...subunit of Na V channels, coassembles with and modulates the biophysical properties of K V1 and K V7 channels, but not K V3 channels, in an isoform-specific manner. Distinct domains of Na Vβ1 are involved in modulation of the different K V channels. Studies with channel chimeras demonstrate that Na Vβ1-mediated changes in activation kinetics and voltage dependence of activation require interaction of Na Vβ1 with the channel’s voltage-sensing domain, whereas changes in inactivation and deactivation require interaction with the channel’s pore domain. A molecular model based on docking studies shows Na Vβ1 lying in the crevice between the voltage-sensing and pore domains of K V channels, making significant contacts with the S1 and S5 segments. Cross-modulation of Na V and K V channels by Na Vβ1 may promote diversity and flexibility in the overall control of cellular excitability and signaling.
•The Kv1.3 channel in T cells is a validated therapeutic target for autoimmune diseases.•The most potent blockers are peptides from scorpions and sea anemones.•Phase 1 clinical trials with dalazatide ...(ShK-186) show highly promising results.•Buccal and pulmonary administration are suitable for delivering Kv1.3-blocking peptides.•Peptides can be conjugated with larger carriers but this may not be necessary for efficacy in vivo.
The voltage-gated Kv1.3 channel in T lymphocytes is a validated therapeutic target for diverse autoimmune diseases. Here we review the discovery of Kv1.3, its physiological role in T cells, and why it is an attractive target for modulating autoimmune responses. We focus on peptide inhibitors because the first Kv1.3-selective inhibitor in human trials is a peptide derived from a marine organism. Two broad classes of peptides block Kv1.3, the first from scorpions and the second from sea anemones. We describe their structures, their binding site in the external vestibule of Kv1.3, how they have been engineered to improve Kv1.3-specificity, and their pharmacokinetic and pharmacodynamic properties. Finally, we highlight the therapeutic potential of Kv1.3 peptide inhibitors to treat autoimmune diseases without compromising protective immune responses.
For more than 25 years, it has been widely appreciated that Ca²⁺ influx is essential to trigger T-lymphocyte activation. Patch clamp analysis, molecular identification, and functional studies using ...blockers and genetic manipulation have shown that a unique contingent of ion channels orchestrates the initiation, intensity, and duration of the Ca²⁺ signal. Five distinct types of ion channels - Kv1.3, KCa3.1, Orai1+ stromal interacting molecule 1 (STIM1) Ca²⁺-release activating Ca²⁺ (CRAC) channel, TRPM7, and Clswell- comprise a network that performs functions vital for ongoing cellular homeostasis and for T-cell activation, offering potential targets for immunomodulation. Most recently, the roles of STIM1 and Orai1 have been revealed in triggering and forming the CRAC channel following T-cell receptor engagement. Kv1.3, KCa3.1, STIM1, and Orai1 have been found to cluster at the immunological synapse following contact with an antigen-presenting cell; we discuss how channels at the synapse might function to modulate local signaling. Immuno-imaging approaches are beginning to shed light on ion channel function in vivo. Importantly, the expression pattern of Ca²⁺ and K⁺ channels and hence the functional network can adapt depending upon the state of differentiation and activation, and this allows for different stages of an immune response to be targeted specifically.
•Recurrent ovarian cancer is a challenging disease with various therapeutic entities. Optimal cytoreduction is the key determinant of survival outcomes. This paper also highlights the importance of ...appropriate patient selection and surgical expertise in optimizing outcomes.
Ovarian cancer is a disease that presents in advanced stage, due to the absence of any specific or overtly dramatic symptoms. The standard of care is primary debulking surgery, followed by chemotherapy. Ovarian cancer recurrence treatment is very challenging and there is always a debate between cytoreduction vs chemotherapy.
The electronic medical records of all patients who underwent secondary cytoreductive surgery for recurrent ovarian cancer between January 2011 and December 2019 were retrieved the patients with platinum sensitive recurrent ovarian cancer who underwent secondary cytoreductive surgery in our department during this time period were included.
A total of 52 patients underwent secondary cytoreductive surgery for recurrent ovarian cancer during the study period. Median treatment free interval after primary treatment was 20 months (range 6–132). The secondary cytoreductive surgery was highly complex in 4(8 %) patients,19 (37 %) had intermediate surgical complexity score, 29 (55 %) had low surgical complexity score according to the Aletti complexity score. Secondary cytoreductive surgery was complete (no macroscopic residual disease) in 31(60 %); Optimal (R1) in 17 (33 %) and suboptimal in only 4 (7 %) of the patients. Out of the 52 patients,8 expired, 16 had a second recurrence, and 10 were lost to follow up over time.
Successful surgery is possible in well selected patients, which in turn can lead to a meaningful progression free and overall survival benefit. Meticulous individualisation of cases should be done keeping in mind the patient’s performance status, prior treatment history & toxicity; distribution & extent of disease, and the patient’s overall life goals.
Peptide toxins found in a wide array of venoms block K+ channels, causing profound physiological and pathological effects. Here we describe the first functional K+ channel-blocking toxin domain in a ...mammalian protein. MMP23 (matrix metalloprotease 23) contains a domain (MMP23TxD) that is evolutionarily related to peptide toxins from sea anemones. MMP23TxD shows close structural similarity to the sea anemone toxins BgK and ShK. Moreover, this domain blocks K+ channels in the nanomolar to low micromolar range (Kv1.6 > Kv1.3 > Kv1.1 = Kv3.2 > Kv1.4, in decreasing order of potency) while sparing other K+ channels (Kv1.2, Kv1.5, Kv1.7, and KCa3.1). Full-length MMP23 suppresses K+ channels by co-localizing with and trapping MMP23TxD-sensitive channels in the ER. Our results provide clues to the structure and function of the vast family of proteins that contain domains related to sea anemone toxins. Evolutionary pressure to maintain a channel-modulatory function may contribute to the conservation of this domain throughout the plant and animal kingdoms.
The tumour necrosis factor (TNF) family ligands BAFF (B-cell activating factor of TNF family) and APRIL (a proliferation-inducing ligand) are essential for B-cell survival and function. Elevated ...serum levels of BAFF and APRIL have been reported earlier in patients with systemic lupus erythematosus (SLE). Since autoantibody formation in the central nervous system (CNS) is a distinct feature of neuropsychiatric SLE (NPSLE), we have investigated whether NPSLE is associated with an enhanced intrathecal production of APRIL and BAFF.
Levels of BAFF and APRIL in cerebrospinal fluid (CSF) and serum from healthy controls, SLE patients without CNS involvement, and patients with NPSLE were determined by enzyme-linked immunosorbent assay. Interleukin-6 (IL-6) levels were determined by an IL-6-specific bioassay.
SLE patients had levels of APRIL in CSF that were more than 20-fold higher and levels of BAFF in CSF that were more than 200-fold higher than those of healthy controls. Separate analyses of SLE patients with and without CNS involvement revealed that NPSLE patients had enhanced levels of APRIL in CSF. BAFF and APRIL were likely produced locally in the CNS as CSF and serum levels did not correlate. Moreover, CSF levels of APRIL correlated with BAFF but not with IL-6, suggesting that APRIL and BAFF in the CNS are regulated together but that they are produced independently of IL-6.
To our knowledge this is the first study to show elevated levels of BAFF and APRIL in CSF of SLE patients. APRIL was augmented in NPSLE patients compared with SLE patients without CNS involvement. APRIL and BAFF antagonists breeching the blood-brain barrier therefore could have beneficial effects on SLE patients, in particular patients with NPSLE.
Voltage-gated Kv1.3 potassium channels are key regulators of T lymphocyte activation, proliferation and cytokine production, by providing the necessary membrane hyper-polarization for calcium influx ...following immune stimulation. It is noteworthy that an accumulating body of
and
evidence links these channels to multiple sclerosis pathophysiology. Here we studied the electrophysiological properties and the transcriptional and translational expression of T lymphocyte Kv1.3 channels in multiple sclerosis, by combining patch clamp recordings, reverse transcription polymerase chain reaction and flow cytometry on freshly isolated peripheral blood T lymphocytes from two patient cohorts with multiple sclerosis, as well as from healthy and disease controls. Our data demonstrate that T lymphocytes in MS, manifest a significant up-regulation of Kv1.3 mRNA, Kv1.3 membrane protein and Kv1.3 current density and therefore of functional membrane channel protein, compared to control groups (
< 0.001). Interestingly, patient sub-grouping shows that Kv1.3 channel density is significantly higher in secondary progressive, compared to relapsing-remitting multiple sclerosis (
< 0.001). Taking into account the tight connection between Kv1.3 channel activity and calcium-dependent processes, our data predict and could partly explain the reported alterations of T lymphocyte function in multiple sclerosis, while they highlight Kv1.3 channels as potential therapeutic targets and peripheral biomarkers for the disease.
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