| 1. |
- Abels, Mia, et al.
(författare)
-
CART is overexpressed in human type 2 diabetic islets and inhibits glucagon secretion and increases insulin secretion
- 2016
-
Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 59:9, s. 1928-1937
-
Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis Insufficient insulin release and hyperglucagonaemia are culprits in type 2 diabetes. Cocaine- and amphetamine-regulated transcript (CART, encoded by Cartpt) affects islet hormone secretion and beta cell survival in vitro in rats, and Cart(-/-) mice have diminished insulin secretion. We aimed to test if CART is differentially regulated in human type 2 diabetic islets and if CART affects insulin and glucagon secretion in vitro in humans and in vivo in mice. Methods CART expression was assessed in human type 2 diabetic and non-diabetic control pancreases and rodent models of diabetes. Insulin and glucagon secretion was examined in isolated islets and in vivo in mice. Ca2+ oscillation patterns and exocytosis were studied in mouse islets. Results We report an important role of CART in human islet function and glucose homeostasis in mice. CART was found to be expressed in human alpha and beta cells and in a subpopulation of mouse beta cells. Notably, CART expression was several fold higher in islets of type 2 diabetic humans and rodents. CART increased insulin secretion in vivo in mice and in human and mouse islets. Furthermore, CART increased beta cell exocytosis, altered the glucose-induced Ca2+ signalling pattern in mouse islets from fast to slow oscillations and improved synchronisation of the oscillations between different islet regions. Finally, CART reduced glucagon secretion in human and mouse islets, as well as in vivo in mice via diminished alpha cell exocytosis. Conclusions/interpretation We conclude that CART is a regulator of glucose homeostasis and could play an important role in the pathophysiology of type 2 diabetes. Based on the ability of CART to increase insulin secretion and reduce glucagon secretion, CART-based agents could be a therapeutic modality in type 2 diabetes.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Blom, Anna, et al.
(författare)
-
Structural requirements for the complement regulatory activities of C4BP
- 2001
-
Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 276:29, s. 27136-27144
-
Tidskriftsartikel (refereegranskat)abstract
- C4b-binding protein (C4BP) is a regulator of the classical complement pathway C3 convertase (C4bC2a complex). It is a disulfide-linked polymer of seven alpha-chains and a unique beta-chain; the alpha- and beta-chains are composed of eight and three complement control protein (CCP) domains, respectively. To elucidate the importance of the polymeric nature of C4BP and the structural requirements for the interaction between C4b and the alpha-chain, 19 recombinant C4BP variants were created. Six truncated monomeric variants, nine polymeric variants in which individual CCPs were deleted, and finally, four variants in which double alanine residues were introduced between CCPs were functionally characterized. The smallest truncated C4BP variant still active in regulating fluid phase C4b comprised CCP1-3. The monomeric variants were less efficient than polymeric C4BP in degrading C4b on cell surfaces. All three N-terminal CCP domains contributed to the binding of C4b and were important for full functional activity; CCP2 and CCP3 were the most important. The spatial arrangements of the first CCPs were found to be important, as introduction of alanine residues between CCPs 1 and 2, CCPs 2 and 3, and CCPs 3 and 4 resulted in functional impairment. The results presented here elucidate the structural requirements of individual CCPs of C4BP, as well as their spatial arrangements within and between subunits for expression of full functional activity.
|
|
| 5. |
- Kallak, Theodora Kunovac, 1985-, et al.
(författare)
-
Higher than expected estradiol levels in aromatase inhibitor-treated, postmenopausal breast cancer patients
- 2012
-
Ingår i: Climacteric. - London, United Kingdom : Informa Healthcare. - 1369-7137 .- 1473-0804. ; 15:5, s. 473-480
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Vaginal estradiol is considered contraindicated in aromatase inhibitor (AI)-treated patients because of the risk of elevated estrogen levels. This leaves limited treatment options for patients experiencing gynecological symptoms. However, in clinical practice, no precise estimation has been performed of circulating estrogens and aromatase index in postmenopausal breast cancer patients on long-lasting AI or tamoxifen treatment.Methods: Steroid hormones were measured using liquid chromatography tandem mass spectrometry (LC-MS/MS) and extraction radioimmunoassay (RIA). Postmenopausal AI-treated patients (n =33) were compared with tamoxifen-treated patients (n =34) and controls without vaginal treatment (n =56), with vaginal estradiol (n =25), or with estriol (n =11) treatment.Results: By use of LC-MS/MS, median (range) estradiol plasma concentrations were 16.7 (2.4-162.6), 31.0 (13.4-77.1), 27.2 (7.8-115.8) and 33.3 (20.3-340.1) pmol/l in AI-treated breast cancer patients, tamoxifen-treated breast cancer patients, postmenopausal controls and postmenopausal controls on vaginal estradiol, respectively. The AI-treated group and subgroups had significantly lower estradiol and estrone concentrations than all other groups (p <0.05). There was extensive interindividual variation in estradiol concentration within the AI-treated group, measured using both LC-MS/MS (2.3-182.0 pmol/l) and extraction RIA (2.4-162.6 pmol/l). The AI-treated group had lower aromatase index compared to all other groups (p <0.05-0.001).Conclusion: Circulating estrogen levels may have been underestimated in previous longitudinal studies of AI-treated breast cancer patients. Additional studies are required to further evaluate the role of circulating estrogens in breast cancer patients suffering from gynecological symptoms.
|
|
| 6. |
- Kask, Jan, et al.
(författare)
-
Mortality in Women With Anorexia Nervosa : The Role of Comorbid Psychiatric Disorders
- 2016
-
Ingår i: Psychosomatic Medicine. - 0033-3174 .- 1534-7796. ; 78:8, s. 910-919
-
Tidskriftsartikel (refereegranskat)abstract
- Objective To investigate mortality in anorexia nervosa (AN) with a psychiatric comorbidity. Methods Using Swedish registers, data for 8069 female inpatients with AN were retrospectively collected for 1973-2010. Mortality patterns were assessed using standardized mortality ratios (SMRs), Cox regression-derived hazard ratios, and incidence rate ratios. A control cohort of 76,995 women was used. Results Patients with AN and a psychiatric comorbidity had higher mortality rates did than those without a comorbidity. The SMRs for patients with AN and a psychiatric comorbidity were 5.4 (95% confidence interval [CI] = 4.6-6.4) and 18.1 (95% CI = 15.2-21.3) for natural and unnatural causes of death, respectively. The SMRs for patients with AN without a comorbidity were 2.8 (95% CI = 2.3-3.5) and 3.1 (95% CI = 2.2-4.1) for natural and unnatural causes of death, respectively. The adjusted hazard ratios for mortality from natural or unnatural causes were 2.0 (95% CI = 1.5-2.7) and 5.7 (95% CI = 3.9-8.2), respectively. Incidence rate ratios comparing patients with AN and controls, both with psychiatric comorbidities, suggest a negative synergistic effect of comorbid AN and psychiatric disorder on mortality, which was greater for unnatural causes of death. Conclusions Mortality in patients with AN was greater in the presence of a psychiatric comorbidity, and even more pronounced for unnatural causes of death and suicides. Substance abuse, especially alcohol use disorder, increased mortality from natural causes of death. These findings highlight the need for early detection and treatment of psychiatric comorbidity in AN, to potentially improve long-term outcomes.
|
|
| 7. |
- Kask, Lena, et al.
(författare)
-
Identification of Novel Downstream Molecules of Tissue Factor Activation by Comparative Proteomic Analysis
- 2014
-
Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 13:2, s. 477-488
-
Tidskriftsartikel (refereegranskat)abstract
- Tissue factor (TF) is both an initiator of blood coagulation and a signaling receptor. Using a proteomic approach, we investigated the role of TF in cell signaling when stimulated by its ligand, activated factor VII (FVIIa). From a 2-D difference gel electrophoresis (DIGE) study we found forty one spots that were differentially regulated over time in FVIIa stimulated cells or in comparison to nonstimulated cells. Mass spectrometry identifies 23 out of these as 13 different proteins. One of them, elongation factor 2 (EF-2), was investigated in greater detail by Western blot, a protein synthesis assay and cell cycle analysis. When tissue factor was stimulated by FVIIa, the phosphorylation of EF-2 increased which inactivates this protein. Analyzing the effect using site inactivated FVIIa (FVIIai), as well as the protease activated receptor 2 (PAR-2) agonist SLIGKV, indicated that the inactivation was not PAR-2 dependent. A panel of tissue factor mutants was analyzed further to try to pinpoint what part of the cytoplasmic domain that is needed for this effect. Performing a protein synthesis assay in two different cell lines we could confirm that protein synthesis decreased upon stimulation by FVIIa. Cell cycle analysis showed that FVIIa also promotes a higher degree of cell proliferation.
|
|
| 8. |
- Kask, Lena, et al.
(författare)
-
Proteomic analysis of tissue factor activation
- 2013
-
Ingår i: Journal of Thrombosis and Haemostasis. - 1538-7933 .- 1538-7836. ; 11:S2, s. 379-380
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 9. |
|
|
| 10. |
- Kask, Lena, et al.
(författare)
-
Signatures in in vitro infection of NSC-34 mouse neurons and their cell nucleus with Rickettsia helvetica
- 2023
-
Ingår i: BMC Microbiology. - : BioMed Central (BMC). - 1471-2180. ; 23
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Rickettsia helvetica, a spotted fever rickettsia, is transmitted to humans via ticks in Europe, North Africa, and Asia. The central nervous system is a crucial target for rickettsial diseases, which has been reported for 12 of the 31 species, of which R. helvetica is one. This study aimed, in an experimental model, to identify characteristics of R. helvetica infection in a mouse neuronal cell line, NSC-34.Results: NSC-34, a fusion cell line of mouse motor spinal cord neurons and neuroblastoma cells, was used as a model. Propagation of R. helvetica in neurons was confirmed. Short actin tails were shown at the polar end of the bacteria, which makes it likely that they can move intracellularly, and even spread between cells. Another protein, Sca4, which with the cell adhesion protein vinculin enables the passage of the cell membrane, was expressed during infection. No significant increase in TNF alpha levels was seen in the infected neurons, which is of interest because TNF alpha protects the host cell from infection-induced apoptotic death which is crucial for host cell survival. The bacteria were also shown to invade and grow in the cell nucleus of the neuron.Conclusions: The findings suggest that a R. helvetica infection may be harmful to NSC-34 neurons under these in vitro conditions, but the full effects of the infection on the cell need to be studied further, also on human neurons, to also understand the possible significance of this infection in relation to pathogenetic mechanisms.
|
|
