Fosforylering av α- och β-kedjan i LFA-1 reglerar dess interaktioner med cytoplasmiska proteiner och reglering av VLA-4 integrinet

Inflammation is a defense response of the body to an event of injury or tissue damage. Leukocytes circulating in the bloodstream are stimulated by chemokines released by endothelial cells that enable them to adhere and transmigrate to the site of infection. Leukocyte extravasation from the blood vessels towards the site of inflammation is a sequential and overlapping process involving leukocyte rolling, adhesion and transendothelial migration. Adhesion is critical for T-cell trafficking and antigen recognition and is mediated in part by integrins, a large family of αβ heterodimeric cell surface proteins. The β2-integrin lymphocyte function-associated antigen-1 (LFA-1 /αLβ2) and the β1-integrin very late antigen-4 (VLA-4/α4β1) promote T cell interactions with their ligands intercellular and vascular cell adhesion molecules (ICAMs and VCAMs) respectively which are expressed on endothelial cells. VLA-4 and LFA-1 directly participate in cell arrest under flow, whereas firm adhesion is mediated by LFA-1. Integrins have unique characteristics of signaling in both directions across the membranes. Inside-out signaling occurs by ligand binding to non-integrin receptors, which can activate integrins through intracellular signal transduction whereas outside-in signaling takes place by binding of ligands to the integrin itself. The complex signaling pathways of LFA-1 are regulated by rapid phosphorylation and dephosphorylation events of LFA-1, which affect its binding affinities and subsequently protein-protein interactions. My interest lies how the activation of LFA-1 by inside-out and outside-in signaling affects the phosphorylation of the αL- and β2-chains, the adhesive property of LFA-1, intracellular binding partners and cross-talk with the VLA-4 integrin. In my study, I have found involvement of Tiam1, a Rac GEF (Guanine nucleotide exchange factor) protein as a new key player in the intracellular signaling of LFA-1. Upon LFA-1 activation by inside-out signaling, Tiam1 forms a complex with β2 phosphorylated on Thr-758 and the scaffolding protein 14-3-3, which activates Rac1, an actin-regulating protein. Downregulation of Tiam1 inhibits Rac1 activation and furthermore, it impairs cell adhesion to the LFA-1 ligand ICAM-1. The next finding was that the activation of LFA-1 via inside-out or outside-in signaling downregulates VLA-4 binding to its ligand VCAM-1. When LFA-1 is activated, β2 is phosphorylated on Thr-758, which recruits 14-3-3 and Tiam1 and results in crosstalk to VLA-4. It leads to dephosphorylation of Thr-788/789 on the β1-chain, which results in the recruitment of more filamin but less 14-3-3 to the β1-chain. I have also demonstrated that the activation of LFA-1 by anti-LFA-1 antibodies binding to the extracellular part is mediated through phospholipase C (PLC) and protein kinase C (PKC) activation, which causes the phosphorylation of the Thr-758 on β2-chain. Furthermore, I have shown that the phosphorylation of the LFA-1 αL-chain at Ser-1140 is essential for the functionally significant phosphorylation of the β-chain Thr-758 and protein interaction with the β2-chain. Mutation of Ser-1140 to alanine in the αL-chain significantly decreased Thr-758 phosphorylation of β2-chain after SDF-1α or anti-CD3 activation. α-Actinin is an actin-binding protein, which links integrins to the actin cytoskeleton and is crucial for cell migration. We showed that mutation of Ser-1140 to alanine in the αL-chain affects the α-actinin interaction with the β2-chain and chemotactic directional migration. Phosphorylation and de-phosphorylation of αL- and β2- chains may be a way to regulate adhesion and deadhesion turnover of cells during migration. De-regulation of integrins’ function may lead to auto-immune and chronic inflammatory diseases. Here in this thesis, I have now revealed some novel, important mechanisms of the regulation of the leukocyte integrins. The knowledge of how integrins are regulated could be beneficial in clinical applications as well as for developing drugs with high specificity in future.Inflammation är kroppens försvarsmekanism mot infektioner och vävnadsskador. Leukocyter som cirkulerar i blodet stimuleras av kemokiner, vilka frisätts av inflammerade endotelceller. Det gör att leukocyterna kan binda till endotelcellerna och transmigrera till infektions-stället. Leukocyt-extravasionen från blodkärlen sker stegvis: leukocyterna rullar på endotelcellerna, binder till dem och migrerar genom endotelcellbarriären ut i vävnaderna. Adhesion behövs för att T-celler skall kunna cirkulera i kroppen och för att de skall känna igen antigener. Dessa processer regleras delvis av integriner, en stor proteinfamilj som består av αβ-heterodimerer uttryckta på cellytan. β2- integrinet LFA-1 (lymphocyte function-associated antigen-1, αLβ2) och β1-integrinet VLA-4 (very late antigen-4, α4β1) främjar T-cell interaktioner med ligander på endotelcellytan; ICAM (intercellulär adhesions molekyl) och VCAM (vaskulär adhesionsmolekyl). Endotelcell-interaktioner via T-cellens LFA-1 och VLA-4 möjliggör celladhesion vid flöde, medan stark adhesion regleras främst av LFA-1. Integriner är unika eftersom de kan signalera i två riktningar över membranen. Signalering inifrån-ut sker då olika cellulära receptorer binder ligander, vilket kan aktivera integriner genom intracellulär signalering, medan signalering från utsidan-in sker då ligander binder direkt till integrinet. LFA-1 kan initiera flera intracellulära signaleringssystem. LFA-1-akiverad signalering regleras av snabba fosforyleringar och defosforyleringar, vilket påverkar LFA-1-proteinets affinitet för specifika proteininteraktioner. Jag är intresserad av hur LFA-1-aktivering via inre och yttre mekanismer påverkar fosforyleringen av αL- och β2-kedjorna, proteinets förmåga att binda extracellulära ligander och intracellulära protein samt hur detta påverkar VLA-4-integrinets aktivitet. I mina studier har jag identifierat en ny komponent i en signalkaskad aktiverad av LFA-1, Tiam1, som är ett Rac GEF protein (guanine nucleotide exchange factor). Då LFA-1 aktiveras via intracellulär signalering, byggs ett komplex upp med LFA-1 β2 fosforylerad på treonin-758, proteinet 14-3-3 och Tiam1. Detta komplex aktiverar Rac1 som reglerar aktin-cytoskelettet. Om Tiam1 nedregleras, inhiberas Rac1 aktivering och cellens förmåga att binda LFA-1-liganden ICAM. Vi visade också att LFA-1-aktivering via inre och yttre signaleringsvägar nedreglerar VLA-4 integrinets förmåga att binda liganden VCAM1. När LFA-1 aktiveras, forsforyleras treonin-758 på β2-kedjan, vilket rekryterar 14-3-3 och Tiam1 och leder till korsreglering av VLA-4 via intracellulär signalering. Detta leder till defosforylering av treoninerna 788/789 på β1, ökad VLA-4-binding till filamin men minskad binding till 14-3-3. Jag har också visat att LFA-1 aktivering med extracellulära antikroppar mot LFA-1 sker via fosfolipas C (PLC) och proteinnkinas C (PKC), vilket leder till fosforylering av treonin-758 på β2 kedjan. Vidare har jag visat att fosforylering av αL-kedjans serin-1140 är nödvändigt för att β2-kedjans funktionellt viktiga treonin-758 skall kunna fosforyleras. Om αL-kedjans serin-1440 är muterat till alanin kan β2 kedjans treonin-758 inte fosforyleras i aktiverade celler och β2 fosforyleringen är reducerad efter anti-CD3 aktivering. α-aktinin är ett aktin-bindande protein som länkar integriner till cellens cytoskelett och är nödvändigt för cellmigration. Vi visade att interaktionen mellan α-aktinin och β2-kedjan minskade, och riktad migration var förhindrad i celler där αL-kedjans serin-1140 var muterat till alanin. Fosforylering och defosforylering av αL- and β2-kedjorna kan vara ett sätt reglera adhesion och de-adhesion när cellen rör på sig. Autoimmuna sjukdomar och kroniska inflammationer kan orsakas av felaktig reglering av integrinets funktioner. I denna avhandling har jag identifierat några nya, viktiga regleringsmekanismer för leukocytintegriner. Kunskapen om hur dessa sker kan vara viktig i kliniska applikationer och för att utveckla läkemedel med hög specificitet

Persisting non-albicans candidemia in low birth weight neonates in a tertiary care hospital, Jammu and Kashmir

Background: Neonatal candidemia is among the leading causes of mortality in neonatal intensive care units of the developing countries like India. This work aimed at determining the prevalence of candidemia, spectrum of disease, risk factors and the antifungal susceptibility in low birth weight neonates in neonatal intensive care unit (NICU)’s at a tertiary care level. Methods: This was a prospective cross-sectional study of blood culture positive candidemia cases in neonates admitted to the neonatal intensive care unit of tertiary care hospital, SMHS, Jammu and Kashmir, India, between July 2021 to December 2022. All neonates with a clinical suspicion of candidemia with a positive blood culture (BacT alert) were identified. Patient demographics, clinical details, neonatal risk factors, and laboratory data and antifungal susceptibilities (using VITEK 2 compact system) were recorded and analyzed. Results: A total of 680 neonatal blood culture samples were collected from NICU’s, out of which 88 (12.94%) developed candidemia. Low birth weight (33.33%), indwelling catheters (31.52%), prematurity (31.31%) and prolonged use of antibiotics were important risk factors. The commonest clinical manifestation was feed intolerance 66.1% and respiratory distress 62.2%. Non-albicans candida was seen in majority cases 86.36% with Candida krusei 77.27%. All the Candida spp. showed 100% sensitivity to voriconazole and caspofugin followed by amphotericin B, fluconazole and micafugin. Conclusions: In this study, we focussed on determining the prevalence of candidemia in low birth weight neonates. The persistently emerging non-albicans Candida particularly Candida krusei has emerged as a big concern and needs attention for its prevention and treatment to minimize the morbidity and mortality rate

Prevalence and spectrum of dermatophytes in patients attending a tertiary care hospital Srinagar, Kashmir

Background: Dermatophyte infections are a global health problem but very neglected in Kashmir. India. This work aimed at determining prevalence and spectrum of dermatophytosis isolated from patients attending tertiary care hospital Srinagar. Kashmir.Methods: A total of 510 samples of skin, hair and nail scrapings were collected and processed using standard microscopy (KOH) and cultural methods as per the standard protocol.Results: Out of 510 samples collected, 272 (53.33%) patients were confirmed cases of dermatophytosis (confirmed clinically and on fungal culture). The prevalence of dermatophytosis was significantly associated with age groups of participants with higher infection among those aged 18-32 which accounted for 35.29%, followed by age group 1-17 with 30.14%. Out of 510 samples, 110 ( 21.56%) were both KOH (microscopy) and culture positive, 162 (31.76%) cases were only culture positive and 130 (25.49%) clinical samples were only positive for fungal elements on microscopy. 133 (26.07%) fungal isolates were obtained which included both dermatophyte and non-dermatophytic fungi(excluded in this study). T. mentagrophytes had highest distribution 40.44% among dermatophytes species and T. Unguium 114 (41.96%) accounted for most common site for dermatophytic infections. Poor hygiene was predominant risk factor in 143 cases (52.57%). Patients from lower socioeconomic status were affected more than others (34.92%).Conclusions: In this study we have focused to determine the prevalence, clinical pattern and pathogenic profile of dermatophytosis according to the age, gender, site, and fungal distribution. Improvization of these conditions more accurately can result in decreased incidence of dermatophytosis in this area.

A Statistical Analysis of Stock Performance Linking the Pandemic/Epidemic Outbreaks from 2010 till 2020: A Profound Look into the U.S Stock Market

The paper analyses the stock performance during the pandemic outbreaks from 2010 till 2020, particularly concentrating in the U.S. stock market. The key focus of this dissertation is to highlight the implications of behavioural finance and investments. In order to do this, stock performances are analysed through "fear index", also known as VIX and Daily treasure yield curve rate. Panel data analysis is conducted on the 5 major stock indexes to provide an overall glimpse of the U.S. economy. No primary research (such as Interviews, Surveys etc.) had been conducted to fulfil the study. The paper incorporates both qualitative and quantitative analysis. Quantitative analysis focuses on the three panel data models to determine the statistical significance of the variables, with an additional test to determine the most efficient model. The qualitative part conducts a thorough analysis on the medicine sector, particularly the pharmaceutical industries during epidemic times. Overall, the paper tried to illustrate the importance of market psychologies through various analysis

Study and analysis of motion artifacts for ambulatory electroencephalography

Motion artifacts contribute complexity in acquiring clean electroencephalography (EEG) data. It is one of the major challenges for ambulatory EEG. The performance of mobile health monitoring, neurological disorders diagnosis and surgeries can be significantly improved by reducing the motion artifacts. Although different papers have proposed various novel approaches for removing motion artifacts, the datasets used to validate those algorithms are questionable. In this paper, a unique EEG dataset was presented where ten different activities were performed. No such previous EEG recordings using EMOTIV EEG headset are available in research history that explicitly mentioned and considered a number of daily activities that induced motion artifacts in EEG recordings. Quantitative study shows that in comparison to correlation coefficient, the coherence analysis depicted a better similarity measure between motion artifacts and motion sensor data. Motion artifacts were characterized with very low frequency which overlapped with the Delta rhythm of the EEG. Also, a general wavelet transform based approach was presented to remove motion artifacts. Further experiment and analysis with more similarity metrics and longer recording duration for each activity is required to finalize the characteristics of motion artifacts and henceforth reliably identify and subsequently remove the motion artifacts in the contaminated EEG recordings

The relationship between male factor infertility and Chlamydia infection, still an undecided issue

Background: Seropositivity of Chlamydia trachomatis in men is suggestive of chronic and recurrent infection with this sexually transmitted organism. Most males with urogenital Chlamydia infection have serum immunoglobulin G (IgG) antibodies to C. trachomatis that persist for years. Serologic studies linking C. trachomatis to male infertility and sperm quality lead to highly variable results. The objective of the study was to examine the effect of Chlamydia infection, as determined by Chlamydia seropositivity on semen quality.Methods: One hundred men having semen analysis as part of infertility work up had anti-Chlamydia antibody test. They were grouped into those who are seropositive for Chlamydia antibody IgG and those who were not. The sperm parameters and prevalence of different semen abnormalities were compared between the two groups, Chlamydia positive and Chlamydia negative.Results: There are no significant difference in semen parameters and prevalence of different semen abnormalities between the two groups. The sonographical finding of epididymal cyst is 45.8% in Chlamydia positive compared to 12.2% in Chlamydia negative; the difference is significant.Conclusions: Seropositivity of Chlamydia infection in infertile male is not predictive of semen abnormalities. Serological screening of the male partner for Chlamydia trachomatis provides no more benefit than identifying the female partner at risk of tubal factor infertility and males at risk of epididymal obstruction

Phosphorylation of the α-chain in the integrin LFA-1 enables β2-chain phosphorylation and α-actinin binding required for cell adhesion

The integrin leukocyte function-associated antigen-1 (LFA-1) plays a pivotal role in leukocyte adhesion and migration, but the mechanism(s) by which this integrin is regulated has remained incompletely understood. LFA-1 integrin activity requires phosphorylation of its 2-chain and interactions of its cytoplasmic tail with various cellular proteins. The -chain is constitutively phosphorylated and necessary for cellular adhesion, but how the -chain regulates adhesion has remained enigmatic. We now show that substitution of the -chain phosphorylation site (S1140A) in T cells inhibits the phosphorylation of the functionally important Thr-758 in the 2-chain, binding of -actinin and 14-3-3 protein, and expression of an integrin-activating epitope after treatment with the stromal cell-derived factor-1. The presence of this substitution resulted in a loss of cell adhesion and directional cell migration. Moreover, LFA-1 activation through the T-cell receptor in cells expressing the S1140A LFA-1 variant resulted in less Thr-758 phosphorylation, -actinin and talin binding, and cell adhesion. The finding that the LFA-1 -chain regulates adhesion through the -chain via specific phosphorylation at Ser-1140 in the -chain has not been previously reported and emphasizes that both chains are involved in the regulation of LFA-1 integrin activity.Peer reviewe

Effect of Hydrogen Peroxide Concentration on 100% Cotton Knit Fabric Bleaching

This paper focuses on the effect of different concentration of hydrogen peroxide (an oxidizing bleaching agent) on 100% single jersey cotton knit fabric. Five different concentrations (25%, 30%, 35%, 40% and 45%) of hydrogen peroxide solution (5% stock solution) were adopted for this experiment. For each individual concentration, bleaching was performed in three different quantities (6gm/L, 8gm/L and 10gm/L) at the same temperature (100˚C) and same time (60 minute) cycle. 5gm samples were taken where 1:10 material and liquor ratio was maintained in each operation. Spectrophotometer (data color 650) was used to test the reflectance of all bleached samples, and their bursting strengths were measured by an Auto burst instrument following ISO 13938-1 method. The effects of hydrogen peroxide concentration on various physical properties such as weight loss, absorbency, GSM, bursting strength, and whiteness was studied to minimize the cost of bleaching process by optimizing the concentration of hydrogen peroxide. As majority of industries have concerned to alineate the production cost with maximum quality assurance which has been obtained through bleaching at 30% concentration

Population size, behavior and threats to Indian Skimmers (<i>Rhynchops albicollis</i>) at their largest known wintering site

Bangladesh hosts most of what is left of Indian Skimmer (Rhynchops albicollis) populations, a globally endangered species. Each October-March from 2015-2020, 21 surveys of nonbreeding birds were made in Nijhum Dweep National Park, Bangladesh. High tide or evening roosts were counted from vantage points whenever a buildup or breakdown of skimmer concentrations was noticed, and site use noted by marking all observations of presence and activity on maps. The largest single count was 3,108 skimmers on 18 February 2020, constituting 30-50% of the known global population. Indian Skimmers mostly occurred in Damar Char West and at the tip of the Majher Char. Throughout the day with incoming tide, skimmers moved between preferred roosting areas to forage in the shallows. We describe a unique group-foraging strategy in which skimmers chase fish from deep water to shallow water along the shoreline. Circling high over the tidal channel, the flock of skimmers dives down in unison to just above the water surface, then spreading like a net towards the shore. Raptors caused disturbances to roosting skimmers, and we observed one instance of predation of a skimmer by a White-bellied Sea Eagle (Haliaeetus leucogaster). Human fishing activities disturbed nearshore foraging and shoreline roosting skimmers. We suggest protecting Damar Char West by regulating human activities to minimize disturbance from December to March

MEDICINAL PLANTS AND FORMULATIONS USED BY THE SOREN CLAN OF THE SANTAL TRIBE IN RAJSHAHI DISTRICT, BANGLADESH FOR TREATMENT OF VARIOUS AILMENTS

The Santals form the largest tribal community in northern Bangladesh reside primarily in Rajshahi and Rangpur Divisions, where they live in the districts of Rajshahi, Rangpur, Thakurgaon, Dinajpur, and Panchagarh. Although they are fast losing their traditional medicinal practices, they still have their own medicinal practitioners who rely mostly on medicinal plants for treatment of a variety of ailments. The traditional medicinal practices vary quite extensively between the twelve clans of the Santals. The objective of the present study was to conduct an ethnomedicinal survey amongst the Soren clan of the Santal community residing in two villages of Tanor Santal Para in Rajshahi district to collect information on their use of medicinal plants. Interviews were conducted of the two existing Santal traditional medicinal practitioners of the Soren clan with the help of a semi-structured questionnaire and using the guided field-walk method. Plant specimens as pointed out by the practitioners were collected and pressed on the field and identification completed at the Bangladesh National Herbarium. Information on 53 medicinal plants distributed into 32 families was obtained in this survey. Ailments treated by these plants included skin disorders, respiratory tract disorders, gastro-intestinal disorders, sexual dysfunctions, sexually transmitted diseases, diabetes, helminthiasis, pain, urinary problems, filariasis, leprosy, tuberculosis, epilepsy, snake bite, enlarged heart, and paralysis. The medicinal plants used by the Santals merit further scientific studies for some of their formulations are used to treat diseases like diabetes, paralysis, enlarged heart, tuberculosis, and filariasis for which modern medicine has no known cure or medicines have developed resistant vectors