Human mesenchymal stem cells are recruited to injured liver in a β1-integrin and CD44 dependent manner

Human bone marrow mesenchymal stem cells (hMSCs) have shown benefit in clinical trials of patients with liver disease. Efficient delivery of cells to target organs is critical to improving their effectiveness. This requires an understanding of the mechanisms governing cellular engraftment into the liver. Binding of hMSCs to normal/injured liver tissue, purified extracellular matrices, and human hepatic sinusoidal endothelial cells (HSECs) were quantified in static and flow conditions. To define the mechanisms underpinning hMSC interactions, neutralizing adhesion molecule antibodies were used. Fluorescently labelled hMSCs were infused intraportally into CCl(4) -injured mice with and without neutralizing antibodies. hMSCs expressed high levels of CD29/β1-integrin and CD44. Using liver tissue binding assays, hMSC adhesion was greatest in diseased human liver versus normal liver (32.2 cells/field versus 20.5 cells/field [P = 0.048]). Neutralizing antibodies against CD29 and CD44 reduced hMSC binding to diseased liver by 34% and 35%, respectively (P = 0.05). hMSCs rolled at 528 μm/second on HSECs in flow assays. This rolling was abolished by CD29 blockade on hMSCs and vascular cell adhesion molecule-1 (VCAM-1) blockade on HSECs. Firm adhesion to HSECs was reduced by CD29 (55% [P = 0.002]) and CD44 (51% [P = 0.04]) blockade. Neutralizing antibodies to CD29 and CD44 reduced hepatic engraftment of hMSCs in murine liver from 4.45 cells/field to 2.88 cells/field (P = 0.025) and 2.35 cells/field (P = 0.03), respectively. hMSCs expressed modest levels of chemokine receptors including CCR4, CCR5, and CXCR3, but these made little contribution to hMSC adhesion in this setting. Conclusion: hMSCs bind preferentially to injured liver. Rolling of hMSCs is regulated by CD29/VCAM-1, whereas CD29/CD44 interactions with VCAM-1, fibronectin, and hyaluronan on HSECs determine firm adhesion both in vitro and in vivo as demonstrated using a murine model of liver injury. (HEPATOLOGY 2012;56:1063-1073).     

The antiapoptotic DeltaNp73 is degraded in a c-Jun–dependent manner upon genotoxic stress through the antizyme-mediated pathway

p73, the structural and functional homologue of p53, exists as two major forms: the transactivation-proficient, proapoptotic TAp73 or the transactivation-deficient, antiapoptotic DNp73. Expectedly, expression of both these major forms has to be coordinated precisely to achieve the desired cellular outcome. Genotoxic insults resulting in cell death lead to the stabilization of TAp73, mainly through posttranslational modifications, and the concomitant degradation of DNp73, through poorly understood mechanisms. We have therefore investigated the possible mechanisms of stress-induced DNp73 degradation and show here that c-Jun, the AP-1 family member activated by stress signals and involved in stabilizing TAp73, promotes DNp73 degradation. Genotoxic stress-mediated DNp73 degradation was found to occur in a c-Jun–dependent manner through a ubiquitin-independent but proteasome-dependent mechanism. Absence or down-regulation of c-Jun expression abrogated the reduction of DNp73 levels upon stress insults, whereas overexpression of c-Jun led to its degradation. c-Jun controlled DNp73 degradation through the nonclassical, polyamine-induced antizyme (Az) pathway by regulating the latter’s processing during stress response. Consistently, expression of c-Jun or Az, or addition of polyamines, promoted DNp73 degradation, whereas silencing Az expression or inhibiting Az activity in cells exposed to stress reduced c-Jun–dependent DNp73 degradation. Moreover, Az was able to bind to DNp73. These data together demonstrate the existence of a c-Jun–dependent mechanism regulating the abundance of the antiapoptotic DNp73 in response to genotoxic stress.     

Mindin is upregulated during colitis and may activate NF-��B in a TLR-9 mediated manner

AIM:To investigate the regulation of mindin expression and the signaling pathway involved during inflammation.METHODS:C57BL/6 mice were treated with 3% dextran sulfate sodium (DSS) in drinking water for 6 d to induce acute colitis,and then the colon was harvested for histological analysis or for RNA isolation.mRNA expression of mindin and nuclear factor (NF)-κB p65 was analyzed by quantitative real time polymerase chain reaction (RT-PCR) and mindin expression construct was conf irmed by Western blotting.Mouse macrophage and intestinal epithelial lineage cells were stimulated with different cytokines and toll-like receptor (TLR) ligands,before pNF-κB-luciferase activity was assessed using the Dual-Luciferase reporter assay system.RESULTS:mRNA expression of mindin was upregulated 4.7 ± 1.1 fold compared with the baseline during DSS-induced intestinal inflammation in the mice.Stimulation with CpG-ODN (a known TLR-9 ligand) induced 4.2 ± 0.3 fold upregulation of mindin expression in RAW 264.7 cells.Full-length of mindin was cloned from cDNA of mouse mesenteric lymph node,then the pCMV-Mindin-Flag expression vector was established and the protein expression level was confi rmed.Transfection of the mindin construct and stimulation with CpG-ODN signifi cantly increased the NF-κB-luciferase activity by 2.5 ± 0.3 and 4.5 ± 0.5 fold in RAW264.7 and CMT93 cells,respectively (P < 0.01).CONCLUSION:Mindin expression is upregulated during intestinal inflammation and may induce NF-κB promoter activation in a TLR-9 mediated manner.     

Mindin is upregulated during colitis and may activate NF-κB in a TLR-9 mediated manner

AIM:To investigate the regulation of mindin expression and the signaling pathway involved during inflammation.METHODS:C57BL/6 mice were treated with 3% dextran sulfate sodium (DSS) in drinking water for 6 d to induce acute colitis,and then the colon was harvested for histological analysis or for RNA isolation.mRNA expression of mindin and nuclear factor (NF)-κB p65 was analyzed by quantitative real time polymerase chain reaction (RT-PCR) and mindin expression construct was conf irmed by Western blotting.Mou...     

From the Cover: Ghrelin secretion stimulated by β1-adrenergic receptors in cultured ghrelinoma cells and in fasted mice

Ghrelin, an octanoylated peptide hormone produced in the stomach, rises dramatically in mouse plasma during chronic severe calorie deprivation, an event that is essential to maintain life. The mechanism for this increase is not understood. Here, we study the control of ghrelin secretion in tissue culture cells derived from mice bearing ghrelinomas induced by a tissue-specific SV40 T-antigen transgene. We found that the ghrelin-secreting cells express high levels of mRNA encoding β₁-adrenergic receptors. Addition of norepinephrine or epinephrine to the culture medium stimulated ghrelin secretion, and this effect was blocked by atenolol, a selective β₁-adrenergic antagonist. When WT mice were treated with reserpine to deplete adrenergic neurotransmitters from sympathetic neurons, the fasting-induced increase in plasma ghrelin was blocked. Inhibition was also seen following atenolol administration. We conclude that ghrelin secretion during fasting is induced by adrenergic agents released by sympathetic neurons and acting directly on β₁ receptors on the ghrelin-secreting cells of the stomach.     

Collecting duct renin: a major player in angiotensin II–dependent hypertension

Recently, interest on the role of the renin-angiotensin system (RAS) in the pathophysiology of hypertension has shifted toward greater emphasis on new developments in local RAS in specific tissues. We have focused our recent investigations on the role of the intrarenal-intratubular RAS in hypertension. All of the components needed for angiotensin II generation are present within the various compartments in the kidney. This brief review is focused on recent evidence that inappropriate activation of renin in distal nephron segments, by acting on angiotensinogen generated in the proximal tubule cells and delivered to the distal nephron may contribute to increased distal intrarenal angiotensin II formation, sodium retention, and development and progression of hypertension.     

Dorsal hippocampal N-methyl-D-aspartate glutamatergic and δ-opioidergic systems modulate anxiety behaviors in rats in a noninteractive manner

The present study aimed to investigate the effects of N-methyl-d-aspartate (NMDA)-type glutamate receptor agonist, NMDA, on anxiety-like behavior induced by δ-opioid receptor agents in rats, using the elevated plus maze instrument. The dorsal hippocampus (CA1) is known to play an important role in anxiety formation and modulation. Bilateral administration of different doses of δ-opioid receptor agonist, [d-pen2,5] enkephalin acetate hydrate (1 μg/rat, 2 μg/rat, 5 μg/rat, and 10 μg/rat; 1 μL/rat; 0.5 μL/rat in each side), into CA1 area induced an anxiolytic-like effect, demonstrated by substantial increases in the percent of open arm time (OAT%) and percent of open arm entries (OAE%). Intra-CA1 injection of different doses of δ-opioid receptor antagonist, naltrindole hydrochloride (0.25 μg/rat, 0.5 μg/rat, 1 μg/rat, and 2 μg/rat), produced significant anxiogenic-like behavior. Furthermore, intra-CA1 administration of NMDA glutamate receptor agonist, NMDA (0.125 μg/rat, 0.25 μg/rat, 0.5 μg/rat, and 0.75 μg/rat), increased the OAT% and OAE%, indicating anxiolytic-like behavior. However, administration of different doses of NMDA glutamatergic antagonist, MK801 (0.125 μg/rat, 0.25 μg/rat, 0.5 μg/rat, and 1 μg/rat), showed no significant effect on the OAT% but decreased the OAE% significantly. The ineffective dose of NMDA (0.125 μg/rat), when coadministered with enkephalin (1 μg/rat, 2 μg/rat, 5 μg/rat, and 10 μg/rat), did not decrease the anxiety behavior significantly. An effective dose of NMDA (0.5 μg/rat), in combination with different doses of naltrindole hydrochloride (0.25 μg/rat, 0.5 μg/rat, 1 μg/rat, and 2 μg/rat), demonstrated no significant interaction with the OAT%, OAE%, and locomotor activity. These results suggest that CA1 δ-opioid and NMDA glutamatergic systems modulate anxiety behaviors in a noninteractive manner.     

Dissolution and Precipitation Behaviour during Continuous Heating of Al–Mg–Si Alloys in a Wide Range of Heating Rates

In the present study, the dissolution and precipitation behaviour of four different aluminium alloys (EN AW-6005A, EN AW-6082, EN AW-6016, and EN AW-6181) in four different initial heat treatment conditions (T4, T6, overaged, and soft annealed) was investigated during heating in a wide dynamic range. Differential scanning calorimetry (DSC) was used to record heating curves between 20 and 600 °C. Heating rates were studied from 0.01 K/s to 5 K/s. We paid particular attention to control baseline stability, generating flat baselines and allowing accurate quantitative evaluation of the resulting DSC curves. As the heating rate increases, the individual dissolution and precipitation reactions shift to higher temperatures. The reactions during heating are significantly superimposed and partially run simultaneously. In addition, precipitation and dissolution reactions are increasingly suppressed as the heating rate increases, whereby exothermic precipitation reactions are suppressed earlier than endothermic dissolution reactions. Integrating the heating curves allowed the enthalpy levels of the different initial microstructural conditions to be quantified. Referring to time–temperature–austenitisation diagrams for steels, continuous heating dissolution diagrams for aluminium alloys were constructed to summarise the results in graphical form. These diagrams may support process optimisation in heat treatment shops.     

Is there a role for estrogen and progesterone receptors in gall bladder cancer?

Background/Aims. The concept of metaplastic and non-metaplastic types of gall bladder cancer and the likelihood of hormone receptor expression in the nuclei of tumour cells raised the possibility of a potential role for anti-estrogen therapy in gall bladder cancer. This study was carried out to determine the hormone receptors (ER/PR) expression level in gall bladder cancer using specific immunohistochemical assays and correlate it with patient and tumour histopathological characteristics. Patients and methods. Histopathological tumour specimens of 62 patients who underwent a radical cholecystectomy were analysed. Pronase pretreatment and primary monoclonal antibodies were used to perform immunohistochemical analysis for ER and PR. Results. The histology was adenocarcinoma – predominantly, moderately to poorly differentiated (91%). Gallstones were present in 90% of the individuals. Of the 62 specimens analysed, 62 (100%) and 61 (98%) were negative for ER and PR, respectively. Conclusion. The high incidence of gallstone-related gall bladder cancer in India is associated with metaplasia and a tendency to poorer differentiation in the tumour histology. These tumours are consequently less likely to express hormone receptors. Thus, there does not seem to be a role for anti-hormone therapy in patients with histogenesis similar to that seen in India.     

Hyponatraemia and changes in natraemia during hospitalization for acute heart failure and associations with in-hospital and long-term outcomes – from the ESC-HFA EORP Heart Failure Long-Term Registry

Aims

To comprehensively assess hyponatraemia in acute heart failure (AHF) regarding prevalence, associations, hospital course, and post-discharge outcomes.

Methods and results

Of 8298 patients in the European Society of Cardiology Heart Failure Long-Term Registry hospitalized for AHF with any ejection fraction, 20% presented with hyponatraemia (serum sodium <135 mmol/L). Independent predictors included lower systolic blood pressure, estimated glomerular filtration rate (eGFR) and haemoglobin, along with diabetes, hepatic disease, use of thiazide diuretics, mineralocorticoid receptor antagonists, digoxin, higher doses of loop diuretics, and non-use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and beta-blockers. In-hospital death occurred in 3.3%. The prevalence of hyponatraemia and in-hospital mortality with different combinations were: 9% hyponatraemia both at admission and discharge (hyponatraemia Yes/Yes, in-hospital mortality 6.9%), 11% Yes/No (in-hospital mortality 4.9%), 8% No/Yes (in-hospital mortality 4.7%), and 72% No/No (in-hospital mortality 2.4%). Correction of hyponatraemia was associated with improvement in eGFR. In-hospital development of hyponatraemia was associated with greater diuretic use and worsening eGFR but also more effective decongestion. Among hospital survivors, 12-month mortality was 19% and adjusted hazard ratios (95% confidence intervals) were for hyponatraemia Yes/Yes 1.60 (1.35–1.89), Yes/No 1.35 (1.14–1.59), and No/Yes 1.18 (0.96–1.45). For death or heart failure hospitalization they were 1.38 (1.21–1.58), 1.17 (1.02–1.33), and 1.09 (0.93–1.27), respectively.

Conclusion

Among patients with AHF, 20% had hyponatraemia at admission, which was associated with more advanced heart failure and normalized in half of patients during hospitalization. Admission hyponatraemia (possibly dilutional), especially if it did not resolve, was associated with worse in-hospital and post-discharge outcomes. Hyponatraemia developing during hospitalization (possibly depletional) was associated with lower risk.