In vivo characterization and application of a novel potassium channel-based optogenetic silencer in the healthy and epileptic mouse hippocampus

The performance of available optogenetic inhibitors remains insufficient due to low light sensitivity, short-lasting photocurrents, and unintended changes in ion distributions. To overcome these limitations, a novel potassium channel-based optogenetic silencer was developed and successfully applied in various in vitro and acute in vivo settings (Bernal Sierra et al., 2018). This tool, a two-component construct called PACK, comprises a photoactivated adenylyl cyclase (bPAC) and a cAMP-dependent potassium channel (SthK). Here, we examined the long-term inhibitory action and side effects of the PACK construct in healthy and epileptic adult male mice. We targeted hippocampal CA1 pyramidal cells using a viral vector and enabled illumination of these neurons via an implanted optic fiber. Local field potential (LFP) recordings from the CA1 of freely moving mice revealed significantly reduced neuronal activity during 50-minute intermittent illumination, especially in the beta and gamma frequency ranges. Adversely, PACK expression in healthy mice induced chronic astrogliosis, dispersion of pyramidal cells, and generalized seizures. These side effects were independent of the light application and were also present in mice expressing bPAC without the potassium channel. Additionally, light-activation of bPAC alone increased neuronal activity, presumably via enhanced cAMP signaling. In chronically epileptic mice, the dark activity of bPAC/PACK in CA1 prevented the spread of spontaneous epileptiform activity from the seizure focus to the contralateral bPAC/PACK-expressing hippocampus. Taken together, the PACK tool is a potent optogenetic inhibitor but requires refinement of its light-sensitive domain to avoid unexpected physiological changes.

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Long-term in vivo application of a potassium channel-based optogenetic silencer in the healthy and epileptic mouse hippocampus

BMC Biology ◽

10.1186/s12915-021-01210-1 ◽

2022 ◽

Vol 20 (1) ◽

Author(s):

P. Kleis ◽

E. Paschen ◽

U. Häussler ◽

Y. A. Bernal Sierra ◽

C. A. Haas

Keyword(s):

Side Effects ◽

Potassium Channel ◽

Neuronal Activity ◽

Mammalian Cells ◽

Viral Vector ◽

Epileptiform Activity ◽

Field Potential ◽

Pyramidal Cells

Abstract Background Optogenetic tools allow precise manipulation of neuronal activity via genetically encoded light-sensitive proteins. Currently available optogenetic inhibitors are not suitable for prolonged use due to short-lasting photocurrents, tissue heating, and unintended changes in ion distributions, which may interfere with normal neuron physiology. To overcome these limitations, a novel potassium channel-based optogenetic silencer, named PACK, was recently developed. The PACK tool has two components: a photoactivated adenylyl cyclase from Beggiatoa (bPAC) and a cAMP-dependent potassium channel, SthK, which carries a large, long-lasting potassium current in mammalian cells. Previously, it has been shown that activating the PACK silencer with short light pulses led to a significant reduction of neuronal firing in various in vitro and acute in vivo settings. Here, we examined the viability of performing long-term studies in vivo by looking at the inhibitory action and side effects of PACK and its components in healthy and epileptic adult male mice. Results We targeted hippocampal cornu ammonis (CA1) pyramidal cells using a viral vector and enabled illumination of these neurons via an implanted optic fiber. Local field potential (LFP) recordings from CA1 of freely moving mice revealed significantly reduced neuronal activity during 50-min intermittent (0.1 Hz) illumination, especially in the gamma frequency range. Adversely, PACK expression in healthy mice induced chronic astrogliosis, dispersion of pyramidal cells, and generalized seizures. These side effects were independent of the light application and were also present in mice expressing bPAC without the potassium channel. Light activation of bPAC alone increased neuronal activity, presumably via enhanced cAMP signaling. Furthermore, we applied bPAC and PACK in the contralateral hippocampus of chronically epileptic mice following a unilateral injection of intrahippocampal kainate. Unexpectedly, the expression of bPAC in the contralateral CA1 area was sufficient to prevent the spread of spontaneous epileptiform activity from the seizure focus to the contralateral hippocampus. Conclusion Our study highlights the PACK tool as a potent optogenetic inhibitor in vivo. However, further refinement of its light-sensitive domain is required to avoid unexpected physiological changes.

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Spike Timing of Lacunosom-Moleculare Targeting Interneurons and CA3 Pyramidal Cells During High-Frequency Network Oscillations In Vitro

Journal of Neurophysiology ◽

10.1152/jn.00188.2007 ◽

2007 ◽

Vol 98 (1) ◽

pp. 96-104 ◽

Cited By ~ 20

Author(s):

Jay Spampanato ◽

Istvan Mody

Keyword(s):

High Frequency ◽

Epileptiform Activity ◽

Field Potential ◽

Pyramidal Cells ◽

Gamma Oscillations ◽

Spike Timing ◽

Network Activity ◽

Network Oscillations ◽

Ca3 Pyramidal Cells

Network activity in the 200- to 600-Hz range termed high-frequency oscillations (HFOs) has been detected in epileptic tissue from both humans and rodents and may underlie the mechanism of epileptogenesis in experimental rodent models. Slower network oscillations including theta and gamma oscillations as well as ripples are generated by the complex spike timing and interactions between interneurons and pyramidal cells of the hippocampus. We determined the activity of CA3 pyramidal cells, stratum oriens lacunosum-moleculare (O-LM) and s. radiatum lacunosum-moleculare (R-LM) interneurons during HFO in the in vitro low-Mg2+ model of epileptiform activity in GIN mice. In these animals, interneurons can be identified prior to cell-attached recordings by the expression of green-fluorescent protein (GFP). Simultaneous local field potential recordings from s. pyramidale and on-cell recordings of individual interneurons and principal cells revealed three primary firing behaviors of the active cells: 36% of O-LM interneurons and 60% of pyramidal cells fired action potentials at high frequencies during the HFO. R-LM interneurons were biphasic in that they fired at high frequency at the beginning of the HFO but stopped firing before its end. When considering only the highest frequency component of the oscillations most pyramidal cells fired on the rising phase of the oscillation. These data provide evidence for functional distinction during HFOs within otherwise homogeneous groups of O-LM interneurons and pyramidal cells.

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Modeling unitary fields and the single-neuron contribution to local field potentials in the hippocampus

10.1101/602953 ◽

2019 ◽

Cited By ~ 2

Author(s):

Maria Teleńczuk ◽

Bartosz Teleńczuk ◽

Alain Destexhe

Keyword(s):

Local Field ◽

Computational Models ◽

Pyramidal Neurons ◽

Field Potential ◽

Pyramidal Cells ◽

Inhibitory Synapses ◽

Simple Method ◽

Hippocampal Pyramidal Neurons

AbstractSynaptic currents represent a major contribution to the local field potential (LFP) in brain tissue, but the respective contribution of excitatory and inhibitory synapses is not known. Here, we provide estimates of this contribution by using computational models of hippocampal pyramidal neurons, constrained by in vitro recordings. We focus on the unitary LFP (uLFP) generated by single neurons in the CA3 region of the hippocampus. We first reproduce experimental results for hippocampal basket cells, and in particular how inhibitory uLFP are distributed within hippocampal layers. Next, we calculate the uLFP generated by pyramidal neurons, using morphologically-reconstructed CA3 pyramidal cells. The model shows that the excitatory uLFP is of small amplitude, smaller than inhibitory uLFPs. Indeed, when the two are simulated together, inhibitory uLFPs mask excitatory uLFPs, which might create the illusion that the inhibitory field is generated by pyramidal cells. These results provide an explanation for the observation that excitatory and inhibitory uLFPs are of the same polarity, in vivo and in vitro. These results also show that somatic inhibitory currents are large contributors of the LFP, which is important information to interpret this signal. Finally, the results of our model might form the basis of a simple method to compute the LFP, which could be applied to point neurons for each cell type, thus providing a simple biologically-grounded method to calculate LFPs from neural networks.

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A Comparative Ex Vivo Study of Plasminogen Activators and Proteases for Fibrinolytic Activity and Side Effects in Rabbits

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649213 ◽

1977 ◽

Vol 37 (01) ◽

pp. 154-161 ◽

Cited By ~ 1

Author(s):

B. A Janik ◽

S. E Papaioannou

Keyword(s):

Side Effects ◽

Effective Dose ◽

Fibrinolytic Activity ◽

Ex Vivo ◽

Plasminogen Activators ◽

Assay System ◽

Coagulation Parameters ◽

Ex Vivo Assay

SummaryUrokinase, streptokinase, Brinase, trypsin, and SN 687, a bacterial exoprotease, have been evaluated in an ex vivo assay system. These enzymes were injected into rabbits and the fibrinolytic activity as well as other coagulation parameters were measured by in vitro techniques. Dose-response correlations have been made using the euglobulin lysis time as a measure of fibrinolytic activity and the 50% effective dose has been determined for each enzyme. Loading doses, equal to four times the 50% effective dose, were administered to monitor potential toxicity revealing that Brinase, trypsin, and SN 687 were very toxic at this concentration.Having established the 50% effective dose for each enzyme, further testing was conducted where relevant fibrinolytic and coagulation parameters were measured for up to two days following a 50% effective dose bolus injection of each enzyme. Our results have demonstrated that urokinase and streptokinase are plasminogen activators specifically activating the rabbit fibrinolytic system while Brinase, trypsin and SN 687 increase the general proteolytic activity in vivo.The advantages of this ex vivo assay system for evaluating relative fibrinolytic potencies and side effects for plasminogen activators and fibrinolytic proteases have been discussed.

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Current Status and Future Perspective for Research on Medicinal Plants with Anticancerous Activity and Minimum Cytotoxic Value

Current Drug Targets ◽

10.2174/1389450120666190429120314 ◽

2019 ◽

Vol 20 (12) ◽

pp. 1227-1243

Author(s):

Hina Qamar ◽

Sumbul Rehman ◽

D.K. Chauhan

Keyword(s):

Side Effects ◽

Medicinal Plants ◽

Anticancer Agents ◽

Drug Targets ◽

Psidium Guajava ◽

Current Status ◽

Future Perspective ◽

Wide Range

Cancer is the second leading cause of morbidity and mortality worldwide. Although chemotherapy and radiotherapy enhance the survival rate of cancerous patients but they have several acute toxic effects. Therefore, there is a need to search for new anticancer agents having better efficacy and lesser side effects. In this regard, herbal treatment is found to be a safe method for treating and preventing cancer. Here, an attempt has been made to screen some less explored medicinal plants like Ammania baccifera, Asclepias curassavica, Azadarichta indica, Butea monosperma, Croton tiglium, Hedera nepalensis, Jatropha curcas, Momordica charantia, Moringa oleifera, Psidium guajava, etc. having potent anticancer activity with minimum cytotoxic value (IC50 >3μM) and lesser or negligible toxicity. They are rich in active phytochemicals with a wide range of drug targets. In this study, these medicinal plants were evaluated for dose-dependent cytotoxicological studies via in vitro MTT assay and in vivo tumor models along with some more plants which are reported to have IC50 value in the range of 0.019-0.528 mg/ml. The findings indicate that these plants inhibit tumor growth by their antiproliferative, pro-apoptotic, anti-metastatic and anti-angiogenic molecular targets. They are widely used because of their easy availability, affordable price and having no or sometimes minimal side effects. This review provides a baseline for the discovery of anticancer drugs from medicinal plants having minimum cytotoxic value with minimal side effects and establishment of their analogues for the welfare of mankind.

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Mannose Conjugated Starch Nanoparticles for Preferential Targeting of Liver Cancer

Current Drug Delivery ◽

10.2174/1567201817666200903171124 ◽

2020 ◽

Vol 17 ◽

Author(s):

Akhlesh Kumar Jain ◽

Hitesh Sahu ◽

Keerti Mishra ◽

Suresh Thareja

Keyword(s):

Side Effects ◽

Liver Cancer ◽

Entrapment Efficiency ◽

Xrd Analysis ◽

In Vitro Cytotoxicity ◽

Physical Interaction ◽

Scanning Calorimetry ◽

Starch Nanoparticles

Aim: To design D-Mannose conjugated 5-Fluorouracil (5-FU) loaded Jackfruit seed starch nanoparticles (JFSSNPs) for site specific delivery. Background: Liver cancer is the third leading cause of death in world and fifth most often diagnosed cancer is the major global threat to public health. Treatment of liver cancer with conventional method bears several side effects, thus to undertake these side effects as a formulation challenge, it is necessary to develop novel target specific drug delivery system for the effective and better localization of drug into the proximity of target with restricting the movement of drug in normal tissues. Objective: To optimize and characterize the developed D-Mannose conjugated 5-Fluorouracil (5-FU) loaded Jackfruit seed starch nanoparticles (JFSSNPs) for effective treatment of liver cancer. Materials and methods: 5-FU loaded JFSSNPs were prepared and optimized formulation had higher encapsulation efficiency were conjugated with D-Mannose. These formulations were characterized for size, morphology, zeta potential, X-Ray Diffraction, and Differential Scanning Calorimetry. Potential of NPs were studied using in vitro cytotoxicity assay, in vivo kinetic studies and bio-distribution studies. Result and discussion: 5-Fluorouracil loaded NPs had particle size between 336 to 802nm with drug entrapment efficiency was between 64.2 to 82.3%. In XRD analysis, 5-FU peak was diminished in the diffractogram, which could be attributed to the successful incorporation of drug in amorphous form. DSC study suggests there was no physical interaction between 5- FU and Polymer. NPs showed sustained in vitro 5-FU release up to 2 hours. In vivo, mannose conjugated NPs prolonged the plasma level of 5-FU and assist selective accumulation of 5-FU in the liver (vs other organs spleen, kidney, lungs and heart) compared to unconjugated one and plain drug. Conclusion: In vivo, bio-distribution and plasma profile studies resulted in significantly higher concentration of 5- Fluorouracil liver suggesting that these carriers are efficient, viable, and targeted carrier of 5-FU treatment of liver cancer.

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The Topical Nanodelivery of Vismodegib Enhances Its Skin Penetration and Performance In Vitro While Reducing Its Toxicity In Vivo

Pharmaceutics ◽

10.3390/pharmaceutics13020186 ◽

2021 ◽

Vol 13 (2) ◽

pp. 186

Author(s):

Maria Natalia Calienni ◽

Daniela Maza Vega ◽

C. Facundo Temprana ◽

María Cecilia Izquierdo ◽

David E. Ybarra ◽

...

Keyword(s):

Side Effects ◽

Water Solubility ◽

Polymeric Micelles ◽

Skin Penetration ◽

Distribution Volume ◽

And Performance ◽

Oral Doses ◽

Advanced Basal Cell Carcinoma

Vismodegib is a first-in-class inhibitor for advanced basal cell carcinoma treatment. Its daily oral doses present a high distribution volume and several side effects. We evaluated its skin penetration loaded in diverse nanosystems as potential strategies to reduce side effects and drug quantities. Ultradeformable liposomes, ethosomes, colloidal liquid crystals, and dendrimers were able to transport Vismodegib to deep skin layers, while polymeric micelles failed at this. As lipidic systems were the most effective, we assessed the in vitro and in vivo toxicity of Vismodegib-loaded ultradeformable liposomes, apoptosis, and cellular uptake. Vismodegib emerges as a versatile drug that can be loaded in several delivery systems for topical application. These findings may be also useful for the consideration of topical delivery of other drugs with a low water solubility.

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Potentially Curative Therapeutic Activity of NEO212, a Perillyl Alcohol-Temozolomide Conjugate, in Preclinical Cytarabine-Resistant Models of Acute Myeloid Leukemia

Cancers ◽

10.3390/cancers13143385 ◽

2021 ◽

Vol 13 (14) ◽

pp. 3385

Author(s):

Axel H. Schönthal ◽

Steve Swenson ◽

Radu O. Minea ◽

Hye Na Kim ◽

Heeyeon Cho ◽

...

Keyword(s):

Cell Death ◽

Acute Myeloid Leukemia ◽

Side Effects ◽

Anticancer Activity ◽

Myeloid Leukemia ◽

Perillyl Alcohol ◽

Therapeutic Activity ◽

Acute Myeloid

Despite progress in the treatment of acute myeloid leukemia (AML), the clinical outcome remains suboptimal and many patients are still dying from this disease. First-line treatment consists of chemotherapy, which typically includes cytarabine (AraC), either alone or in combination with anthracyclines, but drug resistance can develop and significantly worsen prognosis. Better treatments are needed. We are developing a novel anticancer compound, NEO212, that was created by covalent conjugation of two different molecules with already established anticancer activity, the alkylating agent temozolomide (TMZ) and the natural monoterpene perillyl alcohol (POH). We investigated the anticancer activity of NEO212 in several in vitro and in vivo models of AML. Human HL60 and U937 AML cell lines, as well as different AraC-resistant AML cell lines, were treated with NEO212 and effects on cell proliferation, cell cycle, and cell death were investigated. Mice with implanted AraC-sensitive or AraC-resistant AML cells were dosed with oral NEO212, and animal survival was monitored. Our in vitro experiments show that treatment of cells with NEO212 results in growth inhibition via potent G2 arrest, which is followed by apoptotic cell death. Intriguingly, NEO212 was equally potent in highly AraC-resistant cells. In vivo, NEO212 treatment strikingly extended survival of AML mice and the majority of treated mice continued to thrive and survive without any signs of illness. At the same time, we were unable to detect toxic side effects of NEO212 treatment. All in all, the absence of side effects, combined with striking therapeutic activity even in an AraC-resistant context, suggests that NEO212 should be developed further toward clinical testing.

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KCNN4 promotes the progression of lung adenocarcinoma by activating the AKT and ERK signaling pathways

Cancer Biomarkers ◽

10.3233/cbm-201045 ◽

2021 ◽

pp. 1-15

Author(s):

Ping Xu ◽

Xiao Mo ◽

Ruixue Xia ◽

Long Jiang ◽

Chengfei Zhang ◽

...

Keyword(s):

Potassium Channels ◽

Lung Adenocarcinoma ◽

Potassium Channel ◽

Signaling Pathways ◽

Epithelial To Mesenchymal Transition ◽

Tumor Biology ◽

Erk Signaling ◽

Mesenchymal Transition

BACKGROUND: Potassium channels, encoded by more than seventy genes, are cell excitability transmembrane proteins and become evident to play essential roles in tumor biology. OBJECTIVE: The deregulation of potassium channel genes has been related to cancer development and patient prognosis. The objective of this study is to understand the role of potassium channels in lung cancer. METHODS: We examined all potassium channel genes and identified that KCNN4 is the most significantly overexpressed one in lung adenocarcinoma. The role and mechanism of KCNN4 in lung adenocarcinoma were further investigated by in vitro cell and molecular assay and in vivo mouse xenograft models. RESULTS: We revealed that the silencing of KCNN4 significantly inhibits cell proliferation, migration, invasion, and tumorigenicity of lung adenocarcinoma. Further studies showed that knockdown of KCNN4 promotes cell apoptosis, induces cell cycle arrested in the S phase, and is associated with the epithelial to mesenchymal transition (EMT) process. Most importantly, we demonstrated that KCNN4 regulates the progression of lung adenocarcinoma through P13K/AKT and MEK/ERK signaling pathways. The use of inhibitors that targeted AKT and ERK also significantly inhibit the proliferation and metastasis of lung adenocarcinoma cells. CONCLUSIONS: This study investigated the function and mechanism of KCNN4 in lung adenocarcinoma. On this basis, this means that KCNN4 can be used as a tumor marker for lung adenocarcinoma and is expected to become an important target for a potential drug.

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A Preclinical Evaluation of the Antitumor Activities of Edible and Medicinal Mushrooms: A Molecular Insight

Integrative Cancer Therapies ◽

10.1177/1534735417736861 ◽

2017 ◽

Vol 17 (2) ◽

pp. 200-209 ◽

Cited By ~ 10

Author(s):

Thomson Patrick Joseph ◽

Warren Chanda ◽

Arshad Ahmed Padhiar ◽

Samana Batool ◽

Shao LiQun ◽

...

Keyword(s):

Side Effects ◽

Biological Activities ◽

Genetic Alterations ◽

In Vivo Models ◽

Medicinal Mushrooms ◽

Chemotherapy Drugs ◽

Development Of Resistance ◽

Preclinical And Clinical Studies

Cancer is the leading cause of morbidity and mortality around the globe. For certain types of cancer, chemotherapy drugs have been extensively used for treatment. However, severe side effects and the development of resistance are the drawbacks of these agents. Therefore, development of new agents with no or minimal side effects is of utmost importance. In this regard, natural compounds are well recognized as drugs in several human ailments, including cancer. One class of fungi, “mushrooms,” contains numerous compounds that exhibit interesting biological activities, including antitumor activity. Many researchers, including our own group, are focusing on the anticancer potential of different mushrooms and the underlying molecular mechanism behind their action. The aim of this review is to discuss PI3K/AKT, Wnt-CTNNB1, and NF-κB signaling pathways, the occurrence of genetic alterations in them, the association of these aberrations with different human cancers and how different nodes of these pathways are targeted by various substances of mushroom origin. We have given evidence to propose the therapeutic attributes and possible mode of molecular actions of various mushroom-originated compounds. However, anticancer effects were typically demonstrated in in vitro and in vivo models and very limited number of studies have been conducted in the human population. It is our belief that this review will help the research community in designing concrete preclinical and clinical studies to test the anticancer potential of mushroom-originated compounds on different cancers harboring particular genetic alteration(s).

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