Pathogenesis of LMNA-related dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a progressive myocardial disease that leads to dilatation of cardiac ventricles, reduced contractile force, and a high risk of sudden cardiac death. The second most common gene mutated in the familial form of DCM is LMNA, and the founder mutation p.S143P is the most frequently reported mutation among Finnish DCM patients. LMNA gene encodes nuclear proteins lamin A/C that constitute the nuclear lamina and regulate several cellular functions, e.g., nuclear stability and gene expression. However, the mechanisms of how lamin mutations cause DCM are poorly understood, and there are no effective treatments available. The aim of this thesis project was to study how the p.S143P LMNA mutation affects cell function and viability and how these alterations contribute to DCM development. Using primary patient fibroblasts and transfection models, we showed that the p.S143P mutant lamin A/C is more nucleoplasmic, soluble, and dynamic compared to wild-type (WT) lamin A/C. Furthermore, in vitro assembly experiments showed that the p.S143P lamin A is not able to form typical filaments but forms disorganized aggregates. The consequences of the p.S143P mutation on induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were investigated in the second substudy, where mutant cells showed similar nucleoplasmic lamin A/C distribution. CMs were challenged with ischemic stress, which caused significant sarcomere damage and apoptosis in mutant CMs. In the third substudy, we analyzed the function of lamin A/C under heat shock (HS). We demonstrated that lamin A/C are hyperphosphorylated under HS in control and patient cells. However, the patient cells were more sensitive to heat stress than control cells, affecting cell survival during HS recovery. In the fourth substudy, we determined the mechanical stress response of the patient cells. Unlike the control cells, the mutant cells showed nuclear rupture, cytoskeletal damage, and cellular disarray under mechanical strain. To conclude, these results show that the p.S143P mutation changes the intrinsic properties of lamin A/C affecting its incorporation into the lamina and mislocalization to the nucleoplasm. Mislocalization of lamins deteriorates the lamina structure, leading to nuclear rupture and cytoskeletal damage under stress. These alterations inevitably contribute to the development of DCM.LMNA-geenimutaatioiden aiheuttaman laajentavan kardiomyopatian syntymekanismit Laajentava kardiomyopatia (DCM) on etenevä sydänlihassairaus, jolle on ominaista sydämen kammioiden laajeneminen, sydämen vajaatoiminta sekä lisääntynyt äkkikuoleman riski. LMNA-geenimutaatiot ovat yksi perinnöllisen DCM:n aiheuttaja ja suomalaisilla DCM potilailla p.S143P on yleisin tunnistettu LMNA-geenimutaatio. Lamiinit muodostavat tumakalvon sisäpinnalle säieverkoston (lamina), joka tukee tuman muotoa sekä säätelee geenien ilmentymistä. LMNA-geenin aiheuttaman DCM:n syntymekanismit ovat edelleen huonosti ymmärrettyjä eikä tautiin ole saatavilla tehokasta hoitomuotoa. Tämän väitöskirjatutkimuksen tavoitteena oli selvittää, miten p.S143P LMNAmutaatio vaikuttaa solujen toimintaan ja elinkelpoisuuteen sekä miten nämä muutokset vaikuttavat DCM syntyyn. Ensimmäisessä osatyössä analysoimme DCM potilailta eristettyjä fibroblasteja sekä transfektoituja soluja ja havaitsimme p.S143P mutaation estävän lamiini A:ta muodostamasta välikokoisia säikeitä, mikä johti proteiinin poikkeavaan sijoittumiseen tuman sisäosaan ja osassa soluista lamiinien aggregoitumiseen. Toisessa osatyössä tutkimme p.S143P mutaation vaikutuksia potilaiden fibroblasteista kantasolutekniikalla erilaistetuissa sydänsoluissa. Mutaatiota kantavissa sydänsoluissa lamiini A oli vastaavasti sijoittunut enemmän tuman sisäosaan. Iskeemisen stressin aikana, mutanteilla sydänsoluilla havaittiin selvästi enemmän sarkomeerirakenteen vaurioita sekä solukuolemia. Kolmannessa osatyössä tutkimme lamiini A/C:n vastetta lämpösokkiin. Havaitsimme, että lamiini A/C fosforyloituu lämpösokin aikana sekä potilas- että verrokki soluissa. Potilassolut osoittautuivat kuitenkin herkemmäksi lämpösokille kuin verrokkisolut, mikä heikensi potilassolujen elinkelpoisuutta lämpösokin jälkeen. Neljännessä osatyössä tutkimme potilassolujen vastetta mekaaniseen rasitukseen, mikä aiheutti potilassoluille tuman hajoamisen sekä tukirakenteen vaurioita. Tutkimustulosten perusteella voidaan päätellä, että p.S143P mutaatio estää lamin A/C:ta muodostamasta normaaleita välikokoisia säikeitä, mikä johtaa proteiinin poikkeavaan sijaintiin tumassa. Lamiini A/C sijoittuminen tuman sisäosiin heikentää laminan rakennetta ja aiheuttaa tuman hajoamisen sekä tukirangan vaurioita stressin aikana. Nämä tekijät vaikuttavat yhdessä DCM:n kehittymiseen

Shallow-water mining undermines global sustainability goals

Coastal mineral resources are pro-moted as a sustainable option to meet increasing metal demands. However, shallow-water mining contradicts international conserva-tion and sustainability goals and its regulative legislation is still being de-veloped. In the absence of thorough comparisons of different mining practices, there are no justifications in favour of shallow-water mining.Peer reviewe

Temporal and spatial turnover of freshwater diatoms : Implications for bioassessment

Water quality in streams usually changes fast, and sensitive biological indicators are essential for monitoring these changes. Diatoms are widely used in biological stream quality assessments. However, there are temporal and spatial variations in diatom communities that may result in unreliable quality assessments. Under different kinds of environmental stressors, diatoms can produce deformed frustules. Heavy metals are among the most common causes of these teratological forms. In addition to eutrophication and organic pollution, diatoms could potentially be used for indicators of heavy metal enrichment. The aim here was to examine the interannual and intra-annual turnover of stream diatom communities. The focus of this study was on whether specific species traits and species local abundance and regional distribution affected temporal occurrence of diatom species. The study also included an examination of how stable diatom inferred stream classifications are in time and if pure spatial variation in diatoms should be considered when assessing stream water quality based on diatoms. The final aspect of the study was to determine which heavy metals, and to what extent, trigger the occurrence of deformations in diatom Achnanthidium minutissimum. Our results imply that abundant and widely distributed species with larger niches and the ability to attach to the substratum sustain persistent populations in varying environmental conditions typical for streams. The most persistent species are thus perhaps the most reliable species to be used as indicators of water quality. The stream classification based on diatoms resulted in temporally stable and statistically distinct community types. Thus, the results suggest that sampling of diatoms in every three years seems to be a reliable procedure to assess biological water quality. The investigation also revealed that study regions differ in their diatom species composition more than in their environmental features indicating that diatoms are structured not only by the local environment but also by large-scale processes, possibly related to climate, dispersal and history. As diatom species composition varies between regions, future bioassessments would benefit from regional stratification. Finally, study results indicated that two metals, copper and zinc, and a metalloid, antimony, were the most likely triggers of A. minutissimum deformations. The definition of their morphological and quantitative characteristics, along with a better taxonomic circumscription of the affected species, should allow the use of deformations as a reliable indicator of heavy metal enrichment in freshwater habitats.Veden laatu joissa vaihtelee jatkuvasti, ja herkät bioindikaattorit ovat tärkeitä näiden muutoksien havaitsemiseksi. Piileviä käytetään laajalti veden laadun biologisissa seurannoissa. Ajallinen ja paikallinen vaihtelu piileväyhteisöissä voi kuitenkin hankaloittaa veden laadun arviointia. Erilaiset ympäristötekijät voivat myös aiheuttaa epämuodostumia piilevien kuorissa. Raskasmetallit ovat yleisin syy näille epämuodostumille. Rehevöitymisen ja orgaanisen kuormituksen lisäksi piileviä olisi mahdollista käyttää indikaattoreina myös raskasmetallikuormitukselle. Tutkimuksen tavoitteena on selvittää sekä vuosien sisäistä että vuosien välistä vaihtelua virtavesien piileväyhteisöissä. Tutkimuksessa tarkastellaan, vaikuttavatko tietyt piilevälajien ominaisuudet sekä lajien paikallinen runsaus ja alueellinen levinneisyys niiden esiintymiseen ajassa. Tutkimuksessa selvitettiin lisäksi miten vakaita piileviin perustuvat jokiluokittelut ovat ajassa, ja tulisiko myös alueellinen lajiston vaihtelu huomioida veden laadun arvioinneissa. Lopuksi määritettiin mitkä raskasmetallit ja missä määrin aiheuttavat epämuodostumia Achnanthidium minutissimum- lajille. Tulokset osoittavat, että runsaat ja laajalle levinneet lajit, joilla on lisäksi laaja ekologinen lokero ja kyky kiinnittyä alustaansa, ovat pysyvimpiä jokien kaltaisissa vaihtelevissa elinympäristöissä. Pysyvimmät lajit ovat mahdollisesti luotettavimpia veden laadun indikaattoreita. Myös jokien piileviin perustuva luokittelu pysyi vakaana vuosien välillä. Täten piilevien määritys kolmen vuoden välein näyttää olevan luotettava menetelmä veden laadun arvioimiseksi. Tutkimus paljasti myös, että tutkimusalueet eroavat piileväyhteisöiltään enemmän kuin ympäristötekijöiltään. Paikallisten ympäristötekijöiden lisäksi myös laaja-alaisemmat tekijät, kuten ilmasto, levinneisyys ja muut historialliset tekijtä, muokkaavat piileväyhteisöjä. Tulevaisuudessa piilevien alueellinen vaihtelu tulisi ottaa huomioon veden laadun arvioinneissa. Lisäksi tulokset osoittavat, että kaksi metallia, kupari ja sinkki, sekä puolimetalli, antimoni, aiheuttavat todennäköisimmin epämuodostumia A. minutissimum- lajissa. Epämuodostumien yksityiskohtaisempi laadullinen ja määrällinen määrittely, sekä lajin parempi taksonominen tuntemus, mahdollistavat epämuodostumien käytön myös raskasmetallikuormituksen indikaattorina virtavesissä

Genotyping of Hepatitis C virus by nucleotide sequencing: A robust method for a diagnostic laboratory

Abstract Hepatitis C virus (HCV) is a globally significant blood-borne agent causing liver diseases, and it has infected over 170 million people worldwide. HCV is a diverse group of RNA viruses currently divided into genotypes 1–7 as well as subtypes. HCV infection can be treated with antiviral drugs, but the HCV genotype has to be determined for optimal selection of treatment strategy. The aim of this study was to set up a sequencing-based HCV genotyping method suitable for the workflow of a diagnostic laboratory. The established method is robust and stable, and it utilizes a one-step reverse transcription and PCR amplification of the 5’ untranslated region (5’UTR) and partial Core region of the HCV genome. Amplification products are sequenced using the standard Sanger method, and the genotype is determined by using a freely accessible web-based genotyping tool. The method was validated at the Helsinki University Hospital Laboratory using 238 previously genotyped serum samples. • A new one-step RT-PCR method for the amplification of the 5’ untranslated region and partial Core region of hepatitis C virus was established. • HCV genotype is determined using Sanger sequencing and a freely accessible, easy-to-use web-based genotyping tool. • The method is robust, reproducible and suitable for diagnostic laboratory workflow, and it requires no costly instrumentation or specialized sequence analysis skills.Peer reviewe

Job Contract at Birth of the First Child as a Predictor of Women’s Labor Market Attachment: Trajectory Analyses over 11 Years

There is a lot of evidence that pre-birth employment and access to parental leave are important predictors of mothers’ labor market attachment after childbirth. This register-based study from Finland aimed to analyze in which ways the type of job contract (none, temporary, or permanent) at the start of maternity leave predicts labor market attachment in the long term. The mother cohorts were followed up for 11 years. Labor market attachment was analyzed with latent class growth analysis, which makes it possible to identify subgroups with differing track and level of development. Lack of employment and having a temporary contract at baseline were associated with slower and weaker labor market attachment irrespective of mother’s age, socioeconomic status, and subsequent births. These findings suggest that the polarization of women into the core and periphery of the labor market structure tends to continue after the birth of the first child. Temporary employment might be an obstacle for having rights for a job-protected family leave and have long-term consequences on the continuity of employment and the division of paid and unpaid work in the family

Patient Aggression and the Wellbeing of Nurses : A Cross-Sectional Survey Study in Psychiatric and Non-Psychiatric Settings

Wellbeing of nurses is associated with patient aggression. Little is known about the differences in these associations between nurses working in different specialties. We aimed to estimate and compare the prevalence of patient aggression and the associations between patient aggression and the wellbeing of nurses in psychiatric and non-psychiatric specialties (medical and surgical, and emergency medicine). A sample of 5288 nurses (923 psychiatric nurses, 4070 medical and surgical nurses, 295 emergency nurses) participated in the study. Subjective measures were used to assess both the occurrence of patient aggression and the wellbeing of nurses (self-rated health, sleep disturbances, psychological distress and perceived work ability). Binary logistic regression with interaction terms was used to compare the associations between patient aggression and the wellbeing of nurses. Psychiatric nurses reported all types of patient aggression more frequently than medical and surgical nurses, whereas nurses working in emergency settings reported physical violence and verbal aggression more frequently than psychiatric nurses. Psychiatric nurses reported poor self-rated health and reduced work ability more frequently than both of the non-psychiatric nursing groups, whereas medical and surgical nurses reported psychological distress and sleep disturbances more often. Psychiatric nurses who had experienced at least one type of patient aggression or mental abuse in the previous year, were less likely to suffer from psychological distress and sleep disturbances compared to medical and surgical nurses. Psychiatric nurses who had experienced physical assaults and armed threats were less likely to suffer from sleep disturbances compared to nurses working in emergency settings. Compared to medical and surgical nurses, psychiatric nurses face patient aggression more often, but certain types of aggression are more common in emergency settings. Psychiatric nurses have worse subjective health and work ability than both of the non-psychiatric nursing groups, while their psychiatric wellbeing is better and they have less sleep problems compared to medical and surgical nurses. Psychiatric nurses maintain better psychiatric wellbeing and experience fewer sleep problems than non-psychiatric nurses after events of exposure to patient aggression. This suggest that more attention should be given to non-psychiatric settings for maintaining the wellbeing of nurses after exposure to patient aggression.Peer reviewe

Network structure of depression symptomology in participants with and without depressive disorder : the population-based Health 2000-2011 study

Purpose Putative causal relations among depressive symptoms in forms of network structures have been of recent interest, with prior studies suggesting that high connectivity of the symptom network may drive the disease process. We examined in detail the network structure of depressive symptoms among participants with and without depressive disorders (DD; consisting of major depressive disorder (MDD) and dysthymia) at two time points. Methods Participants were from the nationally representative Health 2000 and Health 2011 surveys. In 2000 and 2011, there were 5998 healthy participants (DD-) and 595 participants with DD diagnosis (DD+). Depressive symptoms were measured using the 13-item version of the Beck Depression Inventory (BDI). Fused Graphical Lasso was used to estimate network structures, and mixed graphical models were used to assess network connectivity and symptom centrality. Network community structure was examined using the walktrap-algorithm and minimum spanning trees (MST). Symptom centrality was evaluated with expected influence and participation coefficients. Results Overall connectivity did not differ between networks from participants with and without DD, but more simple community structure was observed among those with DD compared to those without DD. Exploratory analyses revealed small differences between the samples in the order of one centrality estimate participation coefficient. Conclusions Community structure, but not overall connectivity of the symptom network, may be different for people with DD compared to people without DD. This difference may be of importance when estimating the overall connectivity differences between groups with and without mental disorders.Peer reviewe

Social isolation and loneliness as risk factors for myocardial infarction, stroke and mortality : UK Biobank cohort study of 479 054 men and women

Objective To examine whether social isolation and loneliness (1) predict acute myocardial infarction (AMI) and stroke among those with no history of AMI or stroke, (2) are related to mortality risk among those with a history of AMI or stroke, and (3) the extent to which these associations are explained by known risk factors or pre-existing chronic conditions. Methods Participants were 479 054 individuals from the UK Biobank. The exposures were self-reported social isolation and loneliness. AMI, stroke and mortality were the outcomes. Results Over 7.1 years, 5731 had first AMI, and 3471 had first stroke. In model adjusted for demographics, social isolation was associated with higher risk of AMI (HR 1.43, 95% CI 1.3 to -1.55) and stroke (HR 1.39, 95% CI 1.25 to 1.54). When adjusted for all the other risk factors, the HR for AMI was attenuated by 84% to 1.07 (95% CI 0.99 to 1.16) and the HR for stroke was attenuated by 83% to 1.06 (95% CI 0.96 to 1.19). Loneliness was associated with higher risk of AMI before (HR 1.49, 95% CI 1.36 to 1.64) but attenuated considerably with adjustments (HR 1.06, 95% CI 0.96 to 1.17). This was also the case for stroke (HR 1.36, 95% CI 1.20 to 1.55 before and HR 1.04, 95% CI 0.91 to 1.19 after adjustments). Social isolation, but not loneliness, was associated with increased mortality in participants with a history of AMI (HR 1.25, 95% CI 1.03 to 1.51) or stroke (HR 1.32, 95% CI 1.08 to 1.61) in the fully adjusted model. Conclusions Isolated and lonely persons are at increased risk of AMI and stroke, and, among those with a history of AMI or stroke, increased risk of death. Most of this risk was explained by conventional risk factors.Peer reviewe