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Carmela Santangelo, Angela Scipioni, Lorella Marselli, Piero Marchetti, and Francesco Dotta

Objective: Suppressor of cytokine signaling (SOCS) proteins negatively regulate signal transduction of several cytokines. Since cytokines participate in the pancreatic islet damage in type 1 diabetes, the aim of our study was to investigate the expression of SOCS-1, -2 and -3 in isolated human islets, in basal conditions and after exposure, in vitro, to a combination of interferon (IFN)-γ, interleukin (IL)-1β and tumor necrosis factor (TNF)-α cytokines and in control and in type 1 diabetic human pancreata, to establish (i) whether SOCS molecules are constitutively expressed in human pancreatic islets and (ii) whether their expression can be modulated in vitro by proinflammatory cytokines or ex vivo by an islet inflammatory process.

Methods: Gene expression of SOCS-1, -2 and -3 was evaluated by RT-PCR in untreated and cytokine-treated isolated human pancreatic islets and their protein expression by immunohistochemistry in control and in type 1 diabetic human pancreata paraffin-embedded sections.

Results: We found that SOCS-1, -2 and -3 mRNA is constitutively, although weakly, expressed in human pancreatic islets, similar to the expression observed in control pancreata by immunohistochemistry. SOCS-1, -2 and -3 mRNA expression was strongly increased in human islets after exposure, in vitro, to IFN-γ, IL-1β and TNF-α. Accordingly, an intense and islet-specific immunohistochemical staining for all three SOCS was detected in pancreata from type 1 diabetic patients.

Conclusion: SOCS-1, -2 and -3 genes are constitutively expressed in human pancreatic islets; their expression increases after exposure to proinflammatory cytokines and during an autoimmune inflammatory process, raising the possibility that these molecules act as key regulators of cytokine signaling in pancreatic islets.

Free access

Roberto Lupi, Silvia Del Guerra, Marco Bugliani, Ugo Boggi, Franco Mosca, Scilla Torri, Stefano Del Prato, and Piero Marchetti

Objective: Data from prospective studies suggest a significant reduction in the risk of new diabetes from drug therapies containing angiotensin-converting enzyme (ACE) inhibitors. Since the renin–angiotensin system (RAS) has been found locally in several tissues and cells, including pancreatic islets, we hypothesized that the positive metabolic effects of ACE inhibitors may be due to a beneficial action of these compounds on insulin-secreting β-cells.

Design and methods: Isolated human pancreatic islets were studied after 24 h of incubation with 22.2 mmol/l glucose, with or without the presence in the incubation medium of 0.5–6.0 mmol/l zofenoprilat or enalaprilat, ACE inhibitor drugs which differ by the presence of a sulphydryl or a carboxyl group in their structural formula. Functional and molecular studies were then performed to assess insulin secretion, redox balance, mRNA and protein expression.

Results: Angiotensinogen, ACE and angiotensin type 1 receptor mRNA expression increased in islets cultured in high glucose; this was similarly prevented by the presence of either ACE inhibitor. As expected, preculture of human islets in high glucose determined a marked reduction in insulin secretion which was associated with enhanced oxidative stress, as shown by increased nitrotyrosine concentrations, and enhanced expression of protein kinase C β and NADPH oxidase. The presence of either of the ACE inhibitors counteracted several of the deleterious effects of high glucose exposure, including reduction of insulin secretion and increased oxidative stress; zofenoprilat showed significantly more marked effects.

Conclusions: These results showed that: (a) RAS molecules are present in human islets and their expression is sensitive to glucose concentration, (b) ACE inhibitors, and in particular zofenoprilat, protect human islets from glucotoxicity and (c) the effects of ACE inhibition are associated with decreased oxidative stress. Together, these findings provide evidence that the possible beneficial effects of ACE inhibitors in human diabetes are due, at least in part, to a protective action on pancreatic β-cells.

Free access

Alessandro Antonelli, Silvia Martina Ferrari, Poupak Fallahi, Piero Berti, Gabriele Materazzi, Ivo Marchetti, Clara Ugolini, Fulvio Basolo, Paolo Miccoli, and Ele Ferrannini

Objective

Anaplastic thyroid cancer (ATC) is often unoperable and chemotherapy and radiotherapy are the main treatments. Until now ‘primary ATC cell cultures’ (ANA) have been developed from surgical biopsies. The possibility to obtain ANA from fine-needle aspiration (FNA-ANA) and to test their sensitivity to different drugs could increase the effectiveness of treatments and avoid unnecessary surgical procedures.

Design

To obtain FNA-ANA from six ATC patients before undergoing surgery and to evaluate the chemosensitivity of FNA-ANA to chemotherapeutic agents and thiazolidinediones (TZD).

Methods and results

FNA-ANA from the six ATC patients were cultured in RPMI 1640 and propagated in DMEM. Chemosensitivity was evaluated by inhibiting the proliferation with increasing concentrations of five different chemotherapeutic agents (bleomycin, cisplatin, gemcitabine, etoposide, and carboplatin) or TZD (rosiglitazone). Chemotherapeutic agents significantly inhibited (P<0.0001) FNA-ANA proliferation, such as TZD (P<0.001); etoposide was the most effective in reducing cell growth. Another ANA culture for each patient was obtained from a biopsy specimen; the results for the chemosensitivity tests were similar to those obtained with FNA-ANA. The V600E BRAF mutation was observed in two ATC patients; the inhibition of proliferation by drugs was similar in tumors with or without V600E BRAF mutation.

Conclusions

Our study demonstrates 1) the possibility to obtain FNA-ANA, and opens the way to the use of FNA-ANA to test the chemosensitivity to different drugs (chemotherapeutic agents or TZD; and possibly the radiosensitivity) in each patient, avoiding unnecessary surgical procedures and the administration of inactive chemotherapeutics; and 2) that etoposide is highly effective in reducing ATC cell growth in vitro.

Restricted access

Maria Lytrivi, Valérie Senée, Paraskevi Salpea, Federica Fantuzzi, Anne Philippi, Baroj Abdulkarim, Toshiaki Sawatani, Sandra Marín-Cañas, Nathalie Pachera, Anne Degavre, Pratibha Singh, Céline Derbois, Doris Lechner, Laurence Ladrière, Mariana Igoillo-Esteve, Cristina Cosentino, Lorella Marselli, Jean-François Deleuze, Piero Marchetti, Décio L Eizirik, Marc Nicolino, Annabelle Chaussenot, Cécile Julier, and Miriam Cnop

Objective

DNAJC3, also known as P58IPK, is an Hsp40 family member that interacts with and inhibits PKR-like ER-localized eIF2α kinase (PERK). Dnajc3 deficiency in mice causes pancreatic β-cell loss and diabetes. Loss-of-function mutations in DNAJC3 cause early-onset diabetes and multisystemic neurodegeneration. The aim of our study was to investigate the genetic cause of early-onset syndromic diabetes in two unrelated patients, and elucidate the mechanisms of β-cell failure in this syndrome.

Methods

Whole exome sequencing was performed and identified variants were confirmed by Sanger sequencing. DNAJC3 was silenced by RNAi in INS-1E cells, primary rat β-cells, human islets, and induced pluripotent stem cell-derived β-cells. β-cell function and apoptosis were assessed, and potential mediators of apoptosis examined.

Results

The two patients presented with juvenile-onset diabetes, short stature, hypothyroidism, neurodegeneration, facial dysmorphism, hypoacusis, microcephaly and skeletal bone deformities. They were heterozygous compound and homozygous for novel loss-of-function mutations in DNAJC3. DNAJC3 silencing did not impair insulin content or secretion. Instead, the knockdown induced rat and human β-cell apoptosis and further sensitized cells to endoplasmic reticulum stress, triggering mitochondrial apoptosis via the pro-apoptototic Bcl-2 proteins BIM and PUMA.

Conclusions

This report confirms previously described features and expands the clinical spectrum of syndromic DNAJC3 diabetes, one of the five monogenic forms of diabetes pertaining to the PERK pathway of the endoplasmic reticulum stress response. DNAJC3 deficiency may lead to β-cell loss through BIM- and PUMA-dependent activation of the mitochondrial pathway of apoptosis.