Comparative in vitro studies on PBN loaded nanoparticles prepared by biodegradable chitosan, PLGA polymers and their PEGylated block copolymers

α-phenyl-N-tert-butyl nitrone (PBN) is a neuroprotective free radical scavenger however it has low in vivo stability and blood residence time. Aim. of this study is to develop a nanoparticle formulation by using different polymeric system which enhance the blood residence time and in vivo stability of PBN and characterize in terms of particle size, zeta potential, morphology, encapsulation efficiency, in vitro release profiles. Chitosan (CS), poly(D,L-lactide-co-glycolide) (PLGA) and their poly(ethylene glycol) (PEG) block co-polymers were used for comparative study. Results showed that particle sizes of CS, CS-PEG, PLGA and PLGA-PEG nanoparticles are between 142-356 nm. PLGA nanoparticles and their block copolymers' nanoparticle have greatly monodisperse distribution. CS and CS-PEG nanoparticles have zeta potential values between 17-40 mV related to amine groups, contrariwise PLGA and PLGA-PEG nanoparticles have negative zeta potential in the range of (-8)-(-19) mV. Encapsulation efficiency and loading capacity for all formulations are between 12-54 %, 9-68 %, respectively. PLGA-PEG nanoparticles are promising for further studies due to their sufficient encapsulation efficiency and in vitro release profilesAuthors would like to acknowledge that this project was financially supported by Tubitak (Scientific Research Project Number: 110S460)S

An aquaporin 4 antisense oligonucleotide loaded, brain targeted nanoparticulate system design

Aquaporins (AQPs), members of the water-channel protein family, are highly expressed in brain tissue especially in astrocytic end-feet. They are important players for water hemostasis during development of cytotoxic as well as vasogenic edema. Increased expression of AQPs is important in pathophysiology of neurological diseases such as neuroinflammation and ischemia. Unfortunately, there are a few pharmacological inhibitors of AQP4 with several side effects limiting their translation as a drug for use in clinical conditions. Another therapeutic approach is using antisense oligonucleotides (ASOs) to block AQP4 activity. These are short, synthetic, modified nucleic acids that bind RNA to modulate its function. However, they cannot pass the blood brain barrier (BBB). To overcome this obstacle we designed a nanoparticulate system made up of chitosan nanoparticles surface modified with PEG and conjugated with monoclonal anti transferrin receptor-1 antibody via streptavidin-biotin binding. The nanocarrier system could be targeted to the transferrin receptor-1 at the brain endothelial capillaries through monoclonal antibodies. It is hypothesized that the nanoparticles could pass the BBB via receptor mediated transcytosis and reach brain parenchyma. Particle size, zeta potential, loading capacity and release profiles of nanoparticles were investigated. It was observed that all types of chitosau (CS) nanoparticles had positive zeta potential values and nanoparticle particle size distribution varied between 100 and 800 nm. The association efficiency of ASOs into the nanoparticles was between 80–97% and the release profiles of the nanoparticles exhibited an initial burst effect followed by a controlled release. The results showed that the designed chitosan based nanocarriers could be a promising carrier system to transport nucleic acid based drugs to brain parenchymaThis study is supported by The Scientific and Technological Research Council of Turkey (TUBITAK, Project Number: 110S460)S

Systemically Administered Brain-Targeted Nanoparticles Transport Peptides across the Blood—Brain Barrier and Provide Neuroprotection

Although growth factors and anti-apoptotic peptides have been shown to be neuroprotective in stroke models, translation of these experimental findings to clinic is hampered by limited penetration of peptides to the brain. Here, we show that a large peptide like the basic fibroblast growth factor (bFGF) and a small peptide inhibitor of caspase-3 (z-DEVD-FMK) can effectively be transported to the brain after systemic administration by incorporating these peptides to brain-targeted nanoparticles (NPs). Chitosan NPs were loaded with peptides and then functionalized by conjugating with antibodies directed against the transferrin receptor-1 on brain endothelia to induce receptor-mediated transcytosis across the blood—brain barrier (BBB). Pre-ischemic systemic administration of bFGF- or z-DEVD-FMK-loaded NPs significantly decreased the infarct volume after 2-hour middle cerebral artery occlusion and 22-hour reperfusion in mice. Co-administration of bFGF- or z-DEVD-FMK-loaded NPs reduced the infarct volume further and provided a 3-hour therapeutic window. bFGF-loaded NPs were histologically detected in the brain parenchyma and also restored ischemia-induced Akt dephosphorylation. The neuroprotection was not observed when receptor-mediated transcytosis was inhibited with imatinib or when bFGF-loaded NPs were not conjugated with the targeting antibody, which enables them to cross the BBB. Nanoparticles targeted to brain are promising drug carriers to transport large as well as small BBB-impermeable therapeutics for neuroprotection against strokeTurgay Dalkara’s work is supported by the Turkish Academy of Sciences. This study is supported by The Scientific and Technological Research Council of Turkey (TUBITAK, Project Number: 109S017)S

Pericyte morphology and function

The proper delivery of blood is essential for healthy neuronal function. The anatomical substrate for this precise mechanism is the neurovascular unit, which is formed by neurons, glial cells, endothelia, smooth muscle cells, and pericytes. Based on their particular location on the vessel wall, morphology, and protein expression, pericytes have been proposed as cells capable of regulating capillary blood flow. Pericytes are located around the microvessels, wrapping them with their processes. Their morphology and protein expression substantially vary along the vascular tree. Their contractibility is mediated by a unique cytoskeleton organization formed by filaments of actin that allows pericyte deformability with the consequent mechanical force transferred to the extracellular matrix for changing the diameter. Pericyte ultrastructure is characterized by large mitochondria likely to provide energy to regulate intracellular calcium concentration and fuel contraction. Accordingly, pericytes with compromised energy show a sustained intracellular calcium increase that leads to persistent microvascular constriction. Pericyte morphology is highly plastic and adapted for varying contractile capability along the microvascular tree, making pericytes ideal cells to regulate the capillary blood flow in response to local neuronal activity. Besides the vascular regulation, pericytes also play a role in the maintenance of the blood-brain/retina barrier, neovascularization and angiogenesis, and leukocyte transmigration. Here, we review the morphological and functional features of the pericytes as well as potential specific markers for the study of pericytes in the brain and retin

Data Of Ascending Cortical Vein Occlusion Induced Spreading Depression

The data presented in this article are related to the research article entitled “Microembolism of single cortical arterioles can induce spreading depression and ischemic injury; a potential trigger for migraine and related MRI lesions” (Donmez-Demir et al., 2018) [1]. This article presents data showing that thrombosis of a small ascending cortical vein (25 µm) in the mouse may also trigger spreading depression as does penetrating arteriole occlusion, although less frequently (22% vs. 100%).PubMe

Farelerde Ağrıya Bağlı Yüz İfadesinin Otomatik Değerlendirilmesi (FARE-MİMİK)

TÜBİTAK EEEAG Proje01.05.2018Moleküler agrı mekanizmalarının temellerinin anlasılmasındaki önemli ilerlemelere veendüstrideki büyük yatırımlara karsın, agrı kesici ilaç gelistirme için yapılan temel arastırma ileklinik uygulama arasındaki translasyonel çalısmalardaki basarılar oldukça sınırlı kalmıstır. Buarayısın önündeki önemli engellerden biri mevcut hayvan modellerindeki sezinlenebilirlik(specifity) basarısının düsük olması, dolayısı ile gelistirilecek ilaçlar için hızlı ve güvenilir birdeneysel tarama testinin bulunmamasıdır. Bu ihtiyacı karsılamaya yönelik olarak bu projede, fare deneylerinde agrı paradigmalarıuygulanarak farelerin yüzlerinde olusan agrı mimiklerinin video kayıtlarından otomatik olarakderecelendirilmesini saglayacak hesaplamalı yöntemlerin gelistirilmesi hedeflenmistir.Literatürde Langford ve ekibi (2010) tarafından gelistirilen Fare YüzburusturmasıDerecelendirmesi (Mouse Grimace Scaling, MGS) isimli manuel bir yöntem mevcuttur.Farelerde agrı mimiklerinin otomatik derecelendirilmesi, hız ve daha tarafsız bir etiketlemebasarısının saglanmasının yanısıra etiketlemeyi manuel olarak yapabilecek uzmanlarınyetistirilmesi zorunlulugunu ortadan kaldırmasından dolayı da önem tasımaktadır. Proje, ortak doktora programı bulunan Hacettepe Üniversitesi (HÜ) ile Orta Dogu TeknikÜniversitesi'nin (ODTÜ) nörolojik bilimler ve teknoloji alanlarındaki deneyimleri bir arayagetirilerek yürütülmüstür. Projede HÜ Nörolojik Bilimler ve Psikiyatri Enstitüsü (NBPE)tarafında yapılan çalısmalarda, iki degisik agrı paradigması kullanılarak farelerde basagrısı vekarın agrısı yaratılmıs, farelerde olusan agrıya baglı yüz ifadeleriyle ilgili video kayıtlarıtoplanmıs, agrı miktarı uzmanlar tarafından manuel derecelendirilerek veri etiketlemesiyapılmıstır. ODTÜ Nörobilim ve Nöroteknoloji (NSNT) - Elektrik ve Elektronik Mühendisligi(EEMB) tarafındaki çalısmalarda ise toplanan video verilerinde fare yüzünün tespit ve takipedilmesini ve yüz ifadelerinden agrının otomatik derecelendirilmesini saglamak üzerebilgisayarla görme ve derin ögrenme adı verilen makine ögrenmesine dayalı hesaplamalıyöntemlerin gelistirilmesi yoluna gidilmistir. Serbest dolasan farelerde otomatik agrı derecelendirmek üzere, bu projede önerilerekgelistirilen 6 kameralı ODTÜ-HÜ gözlem kutusu, farenin hareketlerinin kısıtlandıgı 2 kameralıLangford kutusuna göre daha kullanıslı ve basarılı olmustur. Bu projeyle gelistirilen yöntem,farklı agrıların fare yüz ifadelerinden otomatik tespitinde ve potansiyel agrı kesicilerin hızlıtaranması için tranlasyonel tıp alanında nesnel, kolay uygulanır ve güvenilir bir yaklasımgetirmesi açısından önem tasımaktadır.Despite important improvements in understanding of molecular pain mechanisms and biginvestments in pain industry, translational success of basic science findings into clinicalpractice remained limited. One important limitation is the low specifity of the present animalmodels, and thus, a lack of rapid and reliable experimental tests for screening potentialanalgesic molecules.In order to meet this need, this project aims to develop computational methods thatautomatically grade pain mimics on mouse from video recordings of pain induced mice. Inthe literature there is a manual method named Mouse Grimace Scaling (MGS) developed byLangford et al. (2010). Automatic scoring of pain mimics in mice is also important because itspeeds up and achieves a more neutral labeling success, as well as eliminates the need totrain specialists who can do the labeling manually.The project was carried out by bringing together the expertise of Hacettepe University(HU) and Middle East Technical University (METU) in neurological sciences and technology.Headache and abdominal pain were induced in mice using two different pain paradigms bythe HU Institute of Neurological Sciences and Psychiatry (NBPE) group. Video recordings ofpain-related face expressions in mice were collected and manually scored by trainedexperimenters for data labeling. METU Neuroscience and Neurotechnology (NSNT) groupdeveloped computational methods based on computer vision and machine learning (deeplearning) for mice face detection, tracking and automatic scoring of pain from mice mimics inthe video recordings collected.The 6-camera METU-HU observation box, which was proposed and developed in thisproject for automatic pain rating in freely moving mice, has been more useful and successfulthan the 2-camera Langford box, which restricts the movement of mice. The methodologydeveloped by this project provides an objective, easy-to-implement and reliable approach inthe field of transranial medicine for automatic detection of various painful mouse facialexpressions and rapid screening of potential painkillers.Keywords: pain, headache, migraine, pain paradigms, mouse grimace, automaticfacial expression recognition, computer vision, video processing, machine learning,pattern recognition, biomedical signal processin