Browsing by Subject "SMOOTH-MUSCLE"

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  • Rao, Shailaja P.; Riederer, Monika; Lechleitner, Margarete; Hermansson, Martin; Desoye, Gernot; Hallstroem, Seth; Graier, Wolfgang F.; Frank, Sasa (2013)
  • Malmström, Kristiina; Lohi, Jouko; Malmberg, Leo Pekka; Kotaniemi-Syrjänen, Anne; Lindahl, Harry; Sarna, Seppo; Pelkonen, Anna S.; Mäkelä, Mika J. (2020)
    Abstract Background The relationship of airway hyperresponsiveness to airway remodeling and inflammation in infants with wheeze is unclear. Objective To investigate airway hyperresponsiveness, remodeling and inflammation in infants with wheeze and troublesome breathing. Methods Inclusion criteria: full-term, 3-23 months of age; doctor diagnosed wheeze and persistent recurrent troublesome breathing; without obvious structural defect, suspicion of ciliary dyskinesia, cystic fibrosis, immune deficiency or specified use of corticosteroids. Airway hyperresponsiveness (AHR) was evaluated by performing a methacholine bronchial challenge test combined with whole body pletysmography and rapid thoracoabdominal compression. Endobronchial biopsies were analyzed for remodeling (thickness of reticular basement membrane and amount of airway smooth muscle) and for inflammation (numbers of inflammatory cells). Correlation analyses were performed. Results Forty-nine infants fulfilled the inclusion criteria for the present study. Median age was 1.06 years (IQR 0.6; 1.5). Lung function was impaired in 39/49 (80%) children, at the median age of 1.1 years. Methacholine challenge was successfully performed in 38/49 children. Impaired baseline lung function correlated with AHR (p=0.047, Spearman). In children with the most sensitive quartile of AHR, the percentage of median bronchial airway smooth muscle % and the number of bronchial mast cells in airway smooth muscle were not significantly higher compared to others (p=0.057 and 0.056 respectively). No association was found between AHR and thickness of reticular basement membrane or inflammatory cells. Only a small group of children with both atopy and AHR (the most reactive quartile) had thicker airway smooth muscle area than non-atopics with AHR (p=0.031). Conclusions & Clinical Relevance These findings don not support the concept that AHR in very young children with wheeze is determined by eosinophilic inflammation or clear-cut remodeling although it is associated with impaired baseline lung function. The possible association of increased airway smooth muscle area among atopic children with AHR remains to be confirmed.
  • Malmberg, Leo Pekka; Malmström, Kristiina; Kotaniemi-Syrjänen, Anne; Lohi, Jouko; Pelkonen, Anna S.; Sarna, Seppo; Mäkelä, Mika J. (2020)
  • Boczkowska, Malgorzata; Rebowski, Grzegorz; Kremneva, Elena; Lappalainen, Pekka; Dominguez, Roberto (2015)
    How proteins sharing a common fold have evolved different functions is a fundamental question in biology. Tropomodulins (Tmods) are prototypical actin filament pointed-end-capping proteins, whereas their homologues, Leiomodins (Lmods), are powerful filament nucleators. We show that Tmods and Lmods do not compete biochemically, and display similar but distinct localization in sarcomeres. Changes along the polypeptide chains of Tmods and Lmods exquisitely adapt their functions for capping versus nucleation. Tmods have alternating tropomyosin (TM)- and actin-binding sites (TMBS1, ABS1, TMBS2 and ABS2). Lmods additionally contain a C-terminal extension featuring an actin-binding WH2 domain. Unexpectedly, the different activities of Tmods and Lmods do not arise from the Lmodspecific extension. Instead, nucleation by Lmods depends on two major adaptations-the loss of pointed-end-capping elements present in Tmods and the specialization of the highly conserved ABS2 for recruitment of two or more actin subunits. The WH2 domain plays only an auxiliary role in nucleation.
  • Hukkinen, Maria; Kivisaari, Reetta; Koivusalo, Antti; Pakarinen, Mikko P. (2017)
    Background: In remains unclear why in some short bowel syndrome (SBS) patients, the remaining small bowel (SB) dilates excessively leading to requirement of tapering surgery. Methods: Among SBS children, we retrospectively analyzed risk factors for tapering surgery with logistic regression and compared the outcome of operated patients (n = 16) to those managed conservatively (n = 44) with Cox proportional hazards regression. Results: SBS was caused by necrotizing enterocolitis (NEC) (n = 31), SB atresia (SBA) (n = 13), midgut volvulus (n = 12), or gastroschisis (n = 4). Patients with spontaneous symptomatic SB dilatation unable to wean parenteral nutrition (PN) underwent tapering surgery at median age of 1.04 (interquartile range 0.70-3.27) years. Missing ICV was related to an 8-fold (p = 0.003) increased risk while SBA diagnosis was related to a 13-fold risk of tapering surgery (p <0.001). Increasing SB length and NEC diagnosis were protective of tapering (p = 0.027-0.004). Of operated patients, 75% reached enteral autonomy during follow-up and their postoperative adjusted PN weaning rate was similar to nonoperated children (p = 0.842). Conclusion: SBS children with short remaining SB, missing ICV, and SBA etiology are more likely while NEC patients are less likely than others to necessitate tapering surgery. Postoperative PN weaning rates were comparable to patients who initially had more favorable intestinal anatomy and adapted without surgery. (C) 2017 Elsevier Inc. All rights reserved.
  • Hukkinen, Maria; Kivisaari, Reetta; Merras-Salmio, Laura; Koivusalo, Antti; Pakarinen, Mikko P. (2017)
    Objective: To analyze risk factors and prognostic significance of small bowel (SB) dilatation in children with short bowel syndrome (SBS). Background: In SBS, the remaining SB may dilate as part of intestinal adaptation. The impact of dilatation on parenteral nutrition (PN) dependence and survival has not been studied systematically. Methods: SB diameter of SBS children (n = 61) was measured in contrast SB series (n = 169, median age 0.94, range 0.32-2.7 years) during 2002 to 2015, and expressed as millimeters (SB width) and as ratio to L5 vertebra height (SB diameter ratio). Linear regression was used to examine risk factors for dilatation. PN weaning and survival were analyzed with Cox proportional hazards regression. Results: Maximal SB diameter ratio during follow-up was predicted by PN dependence and SB atresia, while maximal absolute SB width by birth weight, age, PN duration, and remaining bowel length. Weaning off PN was 14-fold more likely in patients with maximal SB diameter ratio <2.00 compared with > 3.00 (P = 0.005), and 5.4-fold more likely when maximal SB width was <20mm compared with > 30mm (P = 0.023). After adjustment for age, remaining SB length, and the presence of ileocecal valve, both estimates of maximal SB dilatation remained significant independent predictors for weaning off PN. When all measurements were included, the cumulative survival was worse if SB diameter ratio exceeded 2.00 (P = 0.002-0.042). Conclusions: SB dilatation predicts prolonged PN duration and decreased survival in SBS children. Measurement of maximal SB diameter standardized to L5 vertebra height may be a valuable objective tool for patient follow-up and assessment of prognosis.
  • Kaerki, Tytti; Rajakylae, Eeva Kaisa; Acheva, Anna; Tojkander, Sari (2020)
    Epithelial integrity is lost upon cancer progression as cancer cells detach from the primary tumor site and start to invade to the surrounding tissues. Invasive cancers of epithelial origin often express altered levels of TRP-family cation channels. Upregulation of TRPV6 Ca2+-channel has been associated with a number of human malignancies and its high expression in breast cancer has been linked to both proliferation and invasive disease. The mechanisms behind the potential of TRPV6 to induce invasive progression have, however, not been well elucidated. Here we show that TRPV6 is connected to both E-cadherin-based adherens junctions and intracellular cytoskeletal structures. Loss of TRPV6 from normal mammary epithelial cells led to disruption of epithelial integrity and abnormal 3D-mammo sphere morphology. Furthermore, expression level of TRPV6 was tightly linked to the levels of common EMT markers, suggesting that TRPV6 may have a role in the mesenchymal invasion of breast cancer cells. Thus, either too low or too high TRPV6 levels compromise homeostasis of the mammary epithelial sheets and may promote the progression of pathophysiological conditions.
  • Lehtimaki, Jaakko I.; Fenix, Aidan M.; Kotila, Tommi M.; Balistreri, Giuseppe; Paavolainen, Lassi; Varjosalo, Markku; Burnette, Dylan T.; Lappalainen, Pekka (2017)
    Contractile actomyosin bundles, stress fibers, are crucial for adhesion, morphogenesis, and mechanosensing in nonmuscle cells. However, the mechanisms by which nonmuscle myosin II (NM-II) is recruited to those structures and assembled into functional bipolar filaments have remained elusive. We report that UNC-45a is a dynamic component of actin stress fibers and functions as a myosin chaperone in vivo. UNC-45a knockout cells display severe defects in stress fiber assembly and consequent abnormalities in cell morphogenesis, polarity, and migration. Experiments combining structured-illumination microscopy, gradient centrifugation, and proteasome inhibition approaches revealed that a large fraction of NM-II and myosin-1c molecules fail to fold in the absence of UNC-45a. The remaining properly folded NM-II molecules display defects in forming functional bipolar filaments. The C-terminal UNC-45/Cro1/She4p domain of UNC-45a is critical for NM-II folding, whereas the N-terminal tetratricopeptide repeat domain contributes to the assembly of functional stress fibers. Thus, UNC-45a promotes generation of contractile actomyosin bundles through synchronized NM-II folding and filament-assembly activities.