DNA Damage and the Activation of the p53 Pathway Mediate Alterations in Metabolic and Secretory Functions of Adipocytes

Activation of the p53 pathway in adipose tissue contributes to insulin resistance associated with obesity. However, the mechanisms of p53 activation and the effect on adipocyte functions are still elusive. Here we found a higher level of DNA oxidation and a reduction in telomere length in adipose tissue of mice fed a high-fat diet and an increase in DNA damage and activation of the p53 pathway in adipocytes. Interestingly, hallmarks of chronic DNA damage are visible at the onset of obesity. Furthermore, injection of lean mice with doxorubicin, a DNA damage-inducing drug, increased the expression of chemokines in adipose tissue and promoted its infiltration by proinflammatory macrophages and neutrophils together with adipocyte insulin resistance. In vitro, DNA damage in adipocytes increased the expression of chemokines and triggered the production of chemotactic factors for macrophages and neutrophils. Insulin signaling and effect on glucose uptake and Glut4 translocation were decreased, and lipolysis was increased. These events were prevented by p53 inhibition, whereas its activation by nutlin-3 reproduced the DNA damage-induced adverse effects. This study reveals that DNA damage in obese adipocytes could trigger p53-dependent signals involved in alteration of adipocyte metabolism and secretory function leading to adipose tissue inflammation, adipocyte dysfunction, and insulin resistance.

Inhibition of Noninfectious Uveitis Using Intravenous Administration of Collagen II-Specific Type 1 Regulatory T Cells

PURPOSE

To evaluate the therapeutic potential of Col-Treg, a collagen II-specific type 1 regulatory T-cell immunotherapy for the treatment of noninfectious uveitis (NIU).

METHODS

Col-Treg cells were produced from collagen II-specific T cell receptor (TCR) transgenic mice or peripheral blood of healthy donors. Phenotypic characterization was performed by flow cytometry, and cytokine secretion was evaluated with Flowcytomix or ELISA. In vitro functional characterization included ATP hydrolysis, cytotoxicity, and contact-independent T-cell suppression and plasticity assays. Col-Treg migration was assessed by quantitative PCR specific to Col-Treg TCR. Col-Treg cells were administered intravenously in mice displaying experimental autoimmune uveitis (EAU) induced by interphotoreceptor retinoid-binding protein (IRBP) immunizations. Efficacy of Col-Treg was assessed by ophthalmology, histology, and immunohistochemistry.

RESULTS

Mice Col-Treg cells displayed identity features of type 1 Treg cells with expression of CD25, FoxP3, low surface expression of CD127, and cytokine secretion profile (IL-10(high), IL-4(low), IFN-γ(int)). In vitro functional assays demonstrated Col-Treg suppressive capacity via soluble factor-dependent immunosuppression, cytotoxicity, and ATP hydrolysis. Col-Treg cells expressed granzyme B, CD39, and glucocorticoid-induced TNF-related protein (GITR). Administration of Col-Treg in EAU mice inhibited clinical and morphologic signs of uveitis and decreased ocular leukocyte infiltration. Col-Treg cells homed in the ocular tissues 24 hours after intravenous injection. Human Col-Treg cells were comparable to mice Col-Treg cells in identity and function and did not show the capacity to differentiate into Th17 cells in vitro.

CONCLUSIONS

These results demonstrate the therapeutic potential of Col-Treg cells as a targeted approach for the treatment of NIU and the feasibility of translating this approach to the human clinical setting.

All tyrosine kinase inhibitor-resistant chronic myelogenous cells are highly sensitive to ponatinib

The advent of tyrosine kinase inhibitor (TKI) therapy has considerably improved the survival of patients suffering chronic myelogenous leukemia (CML). Indeed, inhibition of BCR-ABL by imatinib, dasatinib or nilotinib triggers durable responses in most patients suffering from this disease. Moreover, resistance to imatinib due to kinase domain mutations can be generally circumvented using dasatinib or nilotinib, but the multi-resistant T315I mutation that is insensitive to these TKIs, remains to date a major clinical problem. In this line, ponatinib (AP24534) has emerged as a promising therapeutic option in patients with all kinds of BCR-ABL mutations, especially the T315I one. However and surprisingly, the effect of ponatinib has not been extensively studied on imatinib-resistant CML cell lines. Therefore, in the present study, we used several CML cell lines with different mechanisms of resistance to TKI to evaluate the effect of ponatinib on cell viability, apoptosis and signaling. Our results show that ponatinib is highly effective on both sensitive and resistant CML cell lines, whatever the mode of resistance and also on BaF3 murine B cells carrying native BCR-ABL or T315I mutation. We conclude that ponatinib could be effectively used for all types of TKI-resistant patients.

Simalikalactone E (SkE), a new weapon in the armamentarium of drugs targeting cancers that exhibit constitutive activation of the ERK pathway

Simalikalactone E (SkE) is a quassinoid extracted from a widely used Amazonian antimalarial remedy. Although SkE has previously been shown to have cytostatic and/or cytotoxic activities in some tumor cell lines, its mechanism of action has not yet been characterized. We show here that SkE in the high nanomolar range inhibited the growth of various leukemic and solid tumor cell lines. Importantly, SkE was highly efficient at inhibiting chronic myelogenous leukemia (CML) cells that exhibit constitutive activation of the MAPK pathway and, accordingly, it impaired the phosphorylation of ERK1/2. SkE also abrogated MEK1/2 and B-Raf phosphorylation but had no effect on Ras activity. Moreover, SkE was particularly effective against melanoma cell lines carrying the B-Raf-V600E mutation. Importantly, SkE resensitized the PLX-4032-resistant 451Lu melanoma cell line (451Lu-R) and was more efficient than U0126, a MEK inhibitor, and PLX-4032 (PLX) at inducing the apoptosis of two Hairy Cell Leukemia (HCL) patient samples carrying the B-Raf-V600E mutation. Finally, SkE was as efficient as imatinib at inhibiting tumor formation in a xenograft model of CML cells in athymic mice. In conclusion, we show that SkE, a very potent inhibitor of B-Raf-V600E, is highly effective against cancer cell lines that exhibit constitutive activation of the ERK1/2 pathway.

Ongoing measles outbreak, Geneva, Switzerland, January to March 2011

An outbreak of measles is ongoing in Geneva, Switzerland, since January 2011, in the context of a measles epidemic in neighbouring Rhône-Alpes, France. A total of 41 confirmed cases have been reported, the majority among young adults, many unaware of their non-immune status. There is no large clustering of cases and 14 cases were imported or linked to imported cases. Catch-up vaccination, especially among young adults, may be necessary to prevent further extension of this outbreak.

Dichotomous responses of inter and postprandial hyperglycaemia to short-term calorie restriction in patients with type 2 diabetes

BACKGROUND

In type 2 diabetes the effects of short-term calorie restrictions on glycaemia are usually judged on fasting plasma glucose. As fasting duration rarely exceeds 2-3 h, we determined the effects of calorie restriction over different daytime periods using a continuous glucose monitoring system (CGMS) in noninsulin-using patients with type 2 diabetes.

DESIGN

Fourteen poorly controlled (mean HbA1c = 9.3%) overweight or obese patients (mean body mass index = 30.1 +/- 0.7 kg m(-2)) with type 2 diabetes were investigated twice with a CGMS, at baseline and at the end of a 18-day calorie-restricted diet (1490 kcal day(-1)). Areas under curves (AUCs) of 24-h glucose monitoring were measured and divided into postprandial and interprandial AUCs according to meal times.

RESULTS

Areas under curves of 24-h glucose monitoring were significantly decreased after dieting: -37%, P = 0.0047. Both post and interprandial AUCs were significantly diminished (-26%, P = 0.0186 and -48%, P = 0.0037, respectively), but changes in interprandial AUCs were more marked than changes in postprandial AUCs (P = 0.0060). Nycthemeral peaks of glucose were observed at mid-morning times and were not significantly different before (242 +/- 15 mg dL(-1)) and after dieting (227 +/- 16 mg dL(-1)).

CONCLUSIONS

Short-term calorie restriction in overweight or obese patients with type 2 diabetes resulted in dichotomous responses between interprandial and postprandial glycaemic excursions. The resistance of mid-morning glucose peaking to calorie restriction should result in additional dietary or pharmacological measures at breakfast.

[Treatment of psoriatic rheumatism]

The authors report on the results of a cooperative study done in collaboration with dermatologists and rheumatologists in order to determine the therapeutic incompatibilities resulting from the co-existence of two diseases, both of unknown cause, namely arthropathies and dermopathies. They make an non exhaustive review of the litearature concerning the different medical or physical methods used. They attempt to outline a therapeutic schema according to the different clinical forms and the more or less large extent of the skin disease.

[Study of 108 cases of cervico-brachial neuralgia: the concepts of idiopathic cervico-brachial neuralgia and cervico-arthrotic cervico-brachial neuralgia]

On the basis of a series of 108 cases of cervicobrachial neuralgia a study was made of the clinical characteristics, circumstances of appearance, associated neurological signs, sequelae, relapses, and aetiologies of these observations. This series permits consideration of the aetiopathogenesis of cervicobrachial neuralgias of rheumatic origin from a new angle. The disco-osteophytic nodule does not appear to play the role classically attributed to it. Three forms are distinguished: idiopathic cervicobrachial neuralgia of transient occurrence with a cyclic duration and little tendency to recurrence and not related to concomitant arthrotic lesions; long-term cervicobrachial neuralgia lasting more than 20 weeks and always requiring a search for narrow canal and root anomaly -sometimes the form of onset of cervicarthrotic myelopathies; cervico brachialgia caused by cervicarthrosis seen after the age of 60 and consisting of projected pain rather than true cervicobrachial neuralgia, often recurrent.

[Rheumatic manifestations of Gougerot-Houwers-Sjögren syndrome]

The authors retrospectively survey the concept of the Gougerot-Houwers-5jögren syndrome which links articular disease with the "dry" syndrome (pharyngitis sicca) and then go on to study the rheumatic conditions found in the Gougerot-Houwers-Sjögren syndrome. They point out that the association between the "dry" syndrome and rheumatic appearances varies in frequency according as whether the problem is seen from a rheumatological, dermatological, ophthalmological or stomatological point of view. They establish the frequency of the various rheumatic conditions, stressing the importance of the association with rheumatoid polyarthritis. They study the associated biological and visceral backgrounds, the thyroid, renal, digestive, blood, neural, allergic and immunological conditions and describe the rheumatic appearances of the other collagenoses associated with the "dry" syndrome. They conclude with the current difficulty of restricting the scope of the Gougerot-Houwers-Sjögren syndrome when histological and scintigraphic techniques have broadened it. They would like to see exact criteria adopted to define this syndrome.

[Neurosensory complications of Paget's disease]

The authors made a bibliographic study and report their conclusions with reference to problems concerning a personal series of 17 patients who had undergone an ocular examination, a cranial radiography studying the joint, a bilateral radiotomographic study of the ossicles and of the petrosal bone, an audiogram, and a bilateral electronystagmogram: 1. the rarity of angioid striae, the existence of which, in the view of the authors, does not allow Paget's disease to be included within the framework of the systemized elastorrhexis, 2. the frequency of ocular vascular lesions, 3. deafness is a constant phenomenon, when the cranial arch is affected usually in combination with other lesions ; the deafness is sometimes of transmission or sometimes of perception, but it can precede the cranial lesions. The signs of these can be found radiologically in the chain of ossicles and in the cochlea by means of special projections. The part played by basilar pressure in this deafness is negligible. Labyrinth disorders are rarely met.