The impact of expression vector position on transgene transcription allows for rational expression vector design in a targeted integration system.

Site-specific integration (SSI) technology has emerged as an effective approach by the pharmaceutical industry for the development of recombinant Chinese hamster ovary (CHO) cell lines. While SSI systems have been demonstrated to be effective for the development of CHO cell lines, they can be limiting in terms of both transgene expression and in the case of multi-specifics, the ability to generate the correct product of interest. To maximize the performance of Pfizer's dual SSI expression system for expressing monoclonal and multi-specific antibodies, we used a novel approach to investigate the positional effect of transgenes within expression vectors by engineering nucleotide polymorphisms (NP)s to use as biomarkers to track the level of transcript output from each expression vector position. We observed differences in transcript level for two different transgenes across all four expression vector positions interrogated. We then applied these learnings to rationally design expression vectors for six different mAbs and a multi-specific antibody. We showed enhanced productivity and optimal product quality when compared to a conventional expression vector topology. The learnings gained here can potentially aid in the determination of optimal vector topologies for several IgG-like multi-specific formats.

Risk Factors of Peripheral Vascular Disease in Diabetes Mellitus in Abbottabad, Pakistan: A Cross-Sectional Study.

Introduction Diabetes mellitus (DM) is a significant and common risk factor for the development of peripheral vascular disease (PVD). Peripheral vascular disease is the atherosclerotic narrowing of peripheral arteries and has a high prevalence among patients with diabetes. Material and methods A cross-sectional study was conducted in the Department of Medicine of Ayub Teaching Hospital, Abbottabad. A total of 271 diagnosed diabetic patients aged 40 years or above were included in the study. Ankle-brachial pressure index (ABPI) was measured using a hand-held Doppler device and sphygmomanometer. An ABPI < 0.9 was taken to be abnormal. The risk factors were noted through history taking, physical examination, and appropriate investigations.  Results Our study sample included 271 patients. A hundred and forty-five (53.5%) of them were males, and 126 (46.5%) were females. Fifty-three (19.9%) out of 271 patients had peripheral vascular disease. The prevalence of peripheral vascular disease was stratified among smoking (p=0.00), hypertension (p=0.00), obesity (p=0.004), and hypercholesterolemia (p=0.005) to determine if there was any association between these and peripheral vascular disease. A p-value less than 0.05 was taken to be significant. Conclusion This study showed a significant association between PVD and smoking, hypertension, hypercholesterolemia, and obesity.

Fetal Congenital Heart Block Associated With Maternal Primary Systemic Lupus Erythematosus and Sjogren's Syndrome.

Congenital heart block is a grave condition reported in 0.5% of 100 live births. Systemic lupus erythematosus (SLE) and Sjogren's syndrome (SS) are chronic autoimmune and inflammatory condition, which affects multiple systems. The association of SLE and SS with pregnancy has been seen in the past. Usually, it shows anti-Ro/SSA and anti-Ro/SSB auto-antibodies in maternal serum, which is proportional to fetal Outcome. In this report, we present a case of a 29-year-old female gravida 4, para one and aborta 3, with a history of polycystic ovarian disease and multiple abortions. At 20 weeks of gestation, her antenatal examination revealed fetal bradycardia and heart block, which further led to SLE and SS diagnosis in her. She was treated with steroids to prevent further fetal complications. The patient delivered a healthy neonate at 38 weeks of gestation. The neonate eventually received a cardiac pacemaker and is now on regular follow-up.

Syndrome of Inappropriate Antidiuretic Hormone Secretion-Induced Encephalopathy in a Patient With COVID-19.

Various electrolyte imbalances have been documented in coronavirus disease 2019 (COVID-19) patients who progress to severe acute respiratory syndrome coronavirus-2 infection. Patients with co-morbidities like diabetes, hypertension, obesity, ischemic heart disease, chronic kidney disease, and chronic obstructive pulmonary disease are more vulnerable to developing complications in the form of electrolyte disturbance. We report a case of acute severe hyponatremia in a middle-aged man who was admitted to the hospital with viral pneumonia due to a coronavirus-2 infection. A dramatic drop of plasma sodium was preceded by gastrointestinal symptoms and followed by encephalopathy. On clinical assessment his plasma sodium was found to be critically low, i.e. 105 mmol/L. His chest x-ray showed minimal pleural effusion. The patient was managed in the ICU and his serum sodium was normalized gradually with partial but rapid correction of this severe hyponatremia with hypertonic sodium chloride and followed by fluid restriction.

The Curious Case of Lennox-Gastaut Syndrome: Treatment-Resistant Seizures in a Patient With Autism Spectrum Disease With Lennox-Gastaut Syndrome.

Lennox-Gastaut syndrome (LGS) is a childhood epilepsy disorder seen between the ages of one to eight years with the electroencephalogram (EEG) changes showing slow spiked-wave complex bursts or paroxysms of generalized fast activity and intellectual disability and often needing multiple lines of treatment. Autism spectrum disease (ASD) is rare but catastrophic comorbidity seen in a patient with LGS. We report an eight-year-old boy presenting to the emergency department with seizures and mental retardation. His first seizure was at the age of five months but was symptomatically treated without any specific diagnosis. On further investigation, the patient was diagnosed with LGS with concomitant ASD. The patient has successfully been treated for his treatment-resistant seizures and is now on regular follow-ups. This article aims to highlight this rare combination of LGS along with ASD and understand the disease course.

Differential Modulation of the Voltage-Gated Na+ Channel 1.6 by Peptides Derived From Fibroblast Growth Factor 14.

The voltage-gated Na+ (Nav) channel is a primary molecular determinant of the initiation and propagation of the action potential. Despite the central role of the pore-forming α subunit in conferring this functionality, protein:protein interactions (PPI) between the α subunit and auxiliary proteins are necessary for the full physiological activity of Nav channels. In the central nervous system (CNS), one such PPI occurs between the C-terminal domain of the Nav1.6 channel and fibroblast growth factor 14 (FGF14). Given the primacy of this PPI in regulating the excitability of neurons in clinically relevant brain regions, peptides targeting the FGF14:Nav1.6 PPI interface could be of pre-clinical value. In this work, we pharmacologically evaluated peptides derived from FGF14 that correspond to residues that are at FGF14's PPI interface with the CTD of Nav1.6. These peptides, Pro-Leu-Glu-Val (PLEV) and Glu-Tyr-Tyr-Val (EYYV), which correspond to residues of the ß12 sheet and ß8-ß9 loop of FGF14, respectively, were shown to inhibit FGF14:Nav1.6 complex assembly. In functional studies using whole-cell patch-clamp electrophysiology, PLEV and EYYV were shown to confer differential modulation of Nav1.6-mediated currents through mechanisms dependent upon the presence of FGF14. Crucially, these FGF14-dependent effects of PLEV and EYYV on Nav1.6-mediated currents were further shown to be dependent on the N-terminal domain of FGF14. Overall, these data suggest that the PLEV and EYYV peptides represent scaffolds to interrogate the Nav1.6 channel macromolecular complex in an effort to develop targeted pharmacological modulators.

The Unfamiliar Case of COVID-19 Induced Cerebral Venous Sinus Thrombosis in a Pediatric Patient.

The SARS-CoV-2 virus responsible for COVID-19 infection has affected the world from the end of 2019 with pulmonary and extrapulmonary manifestations. Hematologic complications are a rare but severe complication of the COVID-19 infection. There have been very few cases reported in the past showing thrombotic complications in the pediatric age group. We present a case of a 12-year-old male child showing cerebral venous sinus thrombosis (CVST) who tested positive for COVID-19 at the same time. We highlight the potential of this complication in the pediatric age group and discuss the treatment, which is an infrequent phenomenon.

Popliteal Pterygium With Van Der Woude Syndrome.

Van der Woude syndrome (VWS) is an autosomal dominant syndrome due to mutation of a gene located in the long arm of chromosome 1 (1q32.3-q4) called the interferon regulatory factor-6 (IRF6) gene. VW syndrome-affected children are born with a cleft lip or palate, hypodontia (absent teeth), and bilateral paramedian lower-lip pits, which are usually moist because they are often associated with accessory salivary glands and mucous glands that empty into the pits. Popliteal pterygium syndrome (PPS), also known as a fasciogenito-popliteal syndrome or popliteal web syndrome is a rare autosomal dominant disorder with an incidence of approximately 1 in 300,000 live births. The most common clinical manifestations are popliteal webbing, cleft palate, cleft lip, syndactyly, and genital and nail anomalies. This report describes the clinical features in one case with positive family history, showing the range of anomalies found in popliteal pterygium with VWS.

A KCNC1 mutation in epilepsy of infancy with focal migrating seizures produces functional channels that fail to be regulated by PKC phosphorylation.

Channelopathies caused by mutations in genes encoding ion channels generally produce a clear change in channel function. Accordingly, mutations in KCNC1, which encodes the voltage-dependent Kv3.1 potassium channel, result in progressive myoclonus epilepsy as well as other developmental and epileptic encephalopathies, and these have been shown to reduce or fully abolish current amplitude. One exception to this is the mutation A513V Kv3.1b, located in the cytoplasmic C-terminal domain of the channel protein. This de novo variant was detected in a patient with epilepsy of infancy with focal migrating seizures (EIFMS), but no difference could be detected between A513V Kv3.1 current and that of wild-type Kv3.1. Using both biochemical and electrophysiological approaches, we have now confirmed that this variant produces functional channels but find that the A513V mutation renders the channel completely insensitive to regulation by phosphorylation at S503, a nearby regulatory site in the C-terminus. In this respect, the mutation resembles those in another channel, KCNT1, which are the major cause of EIFMS. Because the amplitude of Kv3.1 current is constantly adjusted by phosphorylation in vivo, our findings suggest that loss of such regulation contributes to EIFMS phenotype and emphasize the role of channel modulation for normal neuronal function.NEW & NOTEWORTHY Ion channel mutations that cause serious human diseases generally alter the biophysical properties or expression of the channel. We describe a de novo mutation in the Kv3.1 potassium channel that causes severe intellectual disability with early-onset epilepsy. The properties of this channel appear identical to those of wild-type channels, but the mutation prevents phosphorylation of the channel by protein kinase C. Our findings emphasize the role of channel modulation in normal brain function.

Mapping of the FGF14:Nav1.6 complex interface reveals FLPK as a functionally active peptide modulating excitability.

The voltage-gated sodium (Nav) channel complex is comprised of pore-forming α subunits (Nav1.1-1.9) and accessory regulatory proteins such as the intracellular fibroblast growth factor 14 (FGF14). The cytosolic Nav1.6 C-terminal tail binds directly to FGF14 and this interaction modifies Nav1.6-mediated currents with effects on intrinsic excitability in the brain. Previous studies have identified the FGF14V160 residue within the FGF14 core domain as a hotspot for the FGF14:Nav1.6 complex formation. Here, we used three short amino acid peptides around FGF14V160 to probe for the FGF14 interaction with the Nav1.6 C-terminal tail and to evaluate the activity of the peptide on Nav1.6-mediated currents. In silico docking predicts FLPK to bind to FGF14V160 with the expectation of interfering with the FGF14:Nav1.6 complex formation, a phenotype that was confirmed by the split-luciferase assay (LCA) and surface plasmon resonance (SPR), respectively. Whole-cell patch-clamp electrophysiology studies demonstrate that FLPK is able to prevent previously reported FGF14-dependent phenotypes of Nav1.6 currents, but that its activity requires the FGF14 N-terminal tail, a domain that has been shown to contribute to Nav1.6 inactivation independently from the FGF14 core domain. In medium spiny neurons in the nucleus accumbens, where both FGF14 and Nav1.6 are abundantly expressed, FLPK significantly increased firing frequency by a mechanism consistent with the ability of the tetrapeptide to interfere with Nav1.6 inactivation and potentiate persistent Na+ currents. Taken together, these results indicate that FLPK might serve as a probe for characterizing molecular determinants of neuronal excitability and a peptide scaffold to develop allosteric modulators of Nav channels.

An Epilepsy-Associated KCNT1 Mutation Enhances Excitability of Human iPSC-Derived Neurons by Increasing Slack KNa Currents.

Mutations in the KCNT1 (Slack, KNa1.1) sodium-activated potassium channel produce severe epileptic encephalopathies. Expression in heterologous systems has shown that the disease-causing mutations give rise to channels that have increased current amplitude. It is not known, however, whether such gain of function occurs in human neurons, nor whether such increased KNa current is expected to suppress or increase the excitability of cortical neurons. Using genetically engineered human induced pluripotent stem cell (iPSC)-derived neurons, we have now found that sodium-dependent potassium currents are increased several-fold in neurons bearing a homozygous P924L mutation. In current-clamp recordings, the increased KNa current in neurons with the P924L mutation acts to shorten the duration of action potentials and to increase the amplitude of the afterhyperpolarization that follows each action potential. Strikingly, the number of action potentials that were evoked by depolarizing currents as well as maximal firing rates were increased in neurons expressing the mutant channel. In networks of spontaneously active neurons, the mean firing rate, the occurrence of rapid bursts of action potentials, and the intensity of firing during the burst were all increased in neurons with the P924L Slack mutation. The feasibility of an increased KNa current to increase firing rates independent of any compensatory changes was validated by numerical simulations. Our findings indicate that gain-of-function in Slack KNa channels causes hyperexcitability in both isolated neurons and in neural networks and occurs by a cell-autonomous mechanism that does not require network interactions.SIGNIFICANCE STATEMENTKCNT1 mutations lead to severe epileptic encephalopathies for which there are no effective treatments. This study is the first demonstration that a KCNT1 mutation increases the Slack current in neurons. It also provides the first explanation for how this increased potassium current induces hyperexcitability, which could be the underlining factor causing seizures.

Identification of peptidomimetics as novel chemical probes modulating fibroblast growth factor 14 (FGF14) and voltage-gated sodium channel 1.6 (Nav1.6) protein-protein interactions.

The voltage-gated sodium (Nav) channel is the molecular determinant of action potential in neurons. Protein-protein interactions (PPI) between the intracellular Nav1.6 C-tail and its regulatory protein fibroblast growth factor 14 (FGF14) provide an ideal and largely untapped opportunity for development of neurochemical probes. Based on a previously identified peptide FLPK, mapped to the FGF14:FGF14 PPI interface, we have designed and synthesized a series of peptidomimetics with the intent of increasing clogP values and improving cell permeability relative to the parental lead peptide. In-cell screening using the split-luciferase complementation (LCA) assay identified ZL0177 (13) as the most potent inhibitor of the FGF14:Nav1.6 channel complex assembly with an apparent IC50 of 11 µM. Whole-cell patch-clamp recordings demonstrated that ZL0177 significantly reduced Nav1.6-mediated transient current density and induced a depolarizing shift of the channel voltage-dependence of activation. Docking studies revealed strong interactions between ZL0177 and Nav1.6, mediated by hydrogen bonds, cation-π interactions and hydrophobic contacts. All together these results suggest that ZL0177 retains some key features of FGF14-dependent modulation of Nav1.6 currents. Overall, ZL0177 provides a chemical scaffold for developing Nav channel modulators as pharmacological probes with therapeutic potential of interest for a broad range of CNS and PNS disorders.

Innate Immune Interactions between Bacillus anthracis and Host Neutrophils.

Bacillus anthracis, the causative agent of anthrax, has been a focus of study in host-pathogen dynamics since the nineteenth century. While the interaction between anthrax and host macrophages has been extensively modeled, comparatively little is known about the effect of anthrax on the immune function of neutrophils, a key frontline effector of innate immune defense. Here we showed that depletion of neutrophils significantly enhanced mortality in a systemic model of anthrax infection in mice. Ex vivo, we found that freshly isolated human neutrophils can rapidly kill anthrax, with specific inhibitor studies showing that phagocytosis and reactive oxygen species (ROS) generation contribute to this efficient bacterial clearance. Anthrax toxins, comprising lethal toxin (LT) and edema toxin (ET), are known to have major roles in B. anthracis macrophage resistance and systemic toxicity. Employing isogenic wild-type and mutant toxin-deficient B. anthracis strains, we show that despite previous studies that reported inhibition of neutrophil function by purified LT or ET, endogenous production of these toxins by live vegetative B. anthracis failed to alter key neutrophil functions. The lack of alteration in neutrophil function is accompanied by rapid killing of B. anthracis by neutrophils, regardless of the bacteria's expression of anthrax toxins. Lastly, our study demonstrates for the first time that anthrax induced neutrophil extracellular trap (NET) formation.

Functional Modulation of Voltage-Gated Sodium Channels by a FGF14-Based Peptidomimetic.

Protein-protein interactions (PPI) offer unexploited opportunities for CNS drug discovery and neurochemical probe development. Here, we present ZL181, a novel peptidomimetic targeting the PPI interface of the voltage-gated Na+ channel Nav1.6 and its regulatory protein fibroblast growth factor 14 (FGF14). ZL181 binds to FGF14 and inhibits its interaction with the Nav1.6 channel C-tail. In HEK-Nav1.6 expressing cells, ZL181 acts synergistically with FGF14 to suppress Nav1.6 current density and to slow kinetics of fast inactivation, but antagonizes FGF14 modulation of steady-state inactivation that is regulated by the N-terminal tail of the protein. In medium spiny neurons in the nucleus accumbens, ZL181 suppresses excitability by a mechanism that is dependent upon expression of FGF14 and is consistent with a state-dependent inhibition of FGF14. Overall, ZL181 and derivatives could lay the ground for developing allosteric modulators of Nav channels that are of interest for a broad range of CNS disorders.

Identification of Amino Acid Residues in Fibroblast Growth Factor 14 (FGF14) Required for Structure-Function Interactions with Voltage-gated Sodium Channel Nav1.6.

The voltage-gated Na(+) (Nav) channel provides the basis for electrical excitability in the brain. This channel is regulated by a number of accessory proteins including fibroblast growth factor 14 (FGF14), a member of the intracellular FGF family. In addition to forming homodimers, FGF14 binds directly to the Nav1.6 channel C-tail, regulating channel gating and expression, properties that are required for intrinsic excitability in neurons. Seeking amino acid residues with unique roles at the protein-protein interaction interface (PPI) of FGF14·Nav1.6, we engineered model-guided mutations of FGF14 and validated their impact on the FGF14·Nav1.6 complex and the FGF14:FGF14 dimer formation using a luciferase assay. Divergence was found in the ß-9 sheet of FGF14 where an alanine (Ala) mutation of Val-160 impaired binding to Nav1.6 but had no effect on FGF14:FGF14 dimer formation. Additional analysis revealed also a key role of residues Lys-74/Ile-76 at the N-terminal of FGF14 in the FGF14·Nav1.6 complex and FGF14:FGF14 dimer formation. Using whole-cell patch clamp electrophysiology, we demonstrated that either the FGF14(V160A) or the FGF14(K74A/I76A) mutation was sufficient to abolish the FGF14-dependent regulation of peak transient Na(+) currents and the voltage-dependent activation and steady-state inactivation of Nav1.6; but only V160A with a concomitant alanine mutation at Tyr-158 could impede FGF14-dependent modulation of the channel fast inactivation. Intrinsic fluorescence spectroscopy of purified proteins confirmed a stronger binding reduction of FGF14(V160A) to the Nav1.6 C-tail compared with FGF14(K74A/I76A) Altogether these studies indicate that the ß-9 sheet and the N terminus of FGF14 are well positioned targets for drug development of PPI-based allosteric modulators of Nav channels.

Split-luciferase complementation assay to detect channel-protein interactions in live cells.

The understanding of ion channel function continues to be a significant driver in molecular pharmacology. In this field of study, protein-protein interactions are emerging as fundamental molecular determinants of ion channel function and as such are becoming an attractive source of highly specific targets for drug development. The investigation of ion channel macromolecular complexes, however, still relies on conventional methods that are usually technically challenging and time-consuming, significantly hampering our ability to identify, characterize and modify ion channel function through targeted molecular approaches. As a response to the urgent need of developing rapid and albeit accurate technologies to survey ion channel molecular complexes, we describe a new application of the split-luciferase complementation assay to study the interaction of the voltage-gated Na + channel with the intracellular fibroblast growth factor 14 and its dynamic regulation in live cells. We envision that the flexibility and accessibility of this assay will have a broad impact in the ion channel field complementing structural and functional studies, enabling the interrogation of protein-channel dynamic interactions in complex cellular contexts and laying the basis for new frameworks in drug discovery campaigns.

Quantitative proteomics reveals protein-protein interactions with fibroblast growth factor 12 as a component of the voltage-gated sodium channel 1.2 (nav1.2) macromolecular complex in Mammalian brain.

Voltage-gated sodium channels (Nav1.1-Nav1.9) are responsible for the initiation and propagation of action potentials in neurons, controlling firing patterns, synaptic transmission and plasticity of the brain circuit. Yet, it is the protein-protein interactions of the macromolecular complex that exert diverse modulatory actions on the channel, dictating its ultimate functional outcome. Despite the fundamental role of Nav channels in the brain, information on its proteome is still lacking. Here we used affinity purification from crude membrane extracts of whole brain followed by quantitative high-resolution mass spectrometry to resolve the identity of Nav1.2 protein interactors. Of the identified putative protein interactors, fibroblast growth factor 12 (FGF12), a member of the nonsecreted intracellular FGF family, exhibited 30-fold enrichment in Nav1.2 purifications compared with other identified proteins. Using confocal microscopy, we visualized native FGF12 in the brain tissue and confirmed that FGF12 forms a complex with Nav1.2 channels at the axonal initial segment, the subcellular specialized domain of neurons required for action potential initiation. Co-immunoprecipitation studies in a heterologous expression system validate Nav1.2 and FGF12 as interactors, whereas patch-clamp electrophysiology reveals that FGF12 acts synergistically with CaMKII, a known kinase regulator of Nav channels, to modulate Nav1.2-encoded currents. In the presence of CaMKII inhibitors we found that FGF12 produces a bidirectional shift in the voltage-dependence of activation (more depolarized) and the steady-state inactivation (more hyperpolarized) of Nav1.2, increasing the channel availability. Although providing the first characterization of the Nav1.2 CNS proteome, we identify FGF12 as a new functionally relevant interactor. Our studies will provide invaluable information to parse out the molecular determinant underlying neuronal excitability and plasticity, and extending the relevance of iFGFs signaling in the normal and diseased brain.

Disease patterns and outcomes of neonatal admissions at a secondary care hospital in pakistan.

OBJECTIVES: This study aimed to determine the disease patterns and outcome of patients admitted to the neonatal unit of a secondary care hospital in Pakistan from January to December 2009. METHODS: Retrospective data from the medical records of all neonates admitted during the study period were reviewed and analysed for age, weight, sex, reason for admission, duration of hospital stay, diagnosis and final outcome. Trends were examined to identify the indicators of inpatient neonatal deaths. RESULTS: The total number of neonates admitted during the study period was 1,554; 979 were male (63%), and 575 were female (37%). A total of 891 patients (57.3%) were born in the hospital while 663 (42.7%) were born elsewhere. The majority were admitted during the first 24 hours of life (51.3%). A total of 13 patients (0.8%) weighed <1 Kg; 85 (5.4%) weighed 1-1.49 Kg, and 587 (37.7%) between 1.5-2.5 Kg. Prematurity and infection were the main reasons for admission (27.9% and 20.33%, respectively), followed by birth asphyxia (13%) and neonatal jaundice (11.3%). A total of 1,287 patients (82.8%) were discharged, 41 left against medical advice (2.6%), 59 were referred to tertiary care hospitals (3.79%) and 106 (6.8%) died. CONCLUSION: Prematurity, low birth weight, birth asphyxia and neonatal jaundice were the major causes of neonatal admissions. This could be reduced by appropriate antenatal care, timely intervention, and in-time referral to tertiary care centres for the deliveries of all high-risk pregnancies. The major cause of neonatal mortality was prematurity.