Inter-organ insulin-leptin signal crosstalk from the liver enhances survival during food shortages.

Crosstalk among organs/tissues is important for regulating systemic metabolism. Here, we demonstrate inter-organ crosstalk between hepatic insulin and hypothalamic leptin actions, which maintains survival during food shortages. In inducible liver insulin receptor knockout mice, body weight is increased with hyperphagia and decreased energy expenditure, accompanied by increased circulating leptin receptor (LepR) and decreased hypothalamic leptin actions. Additional hepatic LepR deficiency reverses these metabolic phenotypes. Thus, decreased hepatic insulin action suppresses hypothalamic leptin action with increased liver-derived soluble LepR. Human hepatic and circulating LepR levels also correlate negatively with hepatic insulin action indices. In mice, food restriction decreases hepatic insulin action and energy expenditure with increased circulating LepR. Hepatic LepR deficiency increases mortality with enhanced energy expenditure during food restriction. The liver translates metabolic cues regarding energy-deficient status, which is reflected by decreased hepatic insulin action, into soluble LepR, thereby suppressing energy dissipation and assuring survival during food shortages.

Two cases with fulminant type 1 diabetes that developed long after cessation of immune checkpoint inhibitor treatment.

Various immune-related adverse events (irAEs), including fulminant type 1 diabetes (FT1D), are known to be associated with immune checkpoint inhibitors (ICIs). We experienced two lung adenocarcinoma cases who developed fulminant type 1 diabetes long after discontinuation of ICI therapies. One, a 74-year-old male, received nivolumab and developed fulminant type 1 diabetes 44 days after the last infusion. The other, an 85-year-old male, received atezolizumab and developed fulminant type 1 diabetes 171 days after the last infusion. Clinical ICI treatment guidelines recommend laboratory tests during ICI treatments but the necessity of tests in patients whose ICI therapy has been discontinued is not clearly described. These cases indicate that blood glucose monitoring should be continued at least for several months, and that patients should be informed of the possibility of fulminant type 1 diabetes after ICI discontinuation, because fulminant type 1 diabetes progresses rapidly and can be life-threatening if not promptly recognized.

SIPA1L1/SPAR1 Interacts with the Neurabin Family of Proteins and is Involved in GPCR Signaling.

Signal-induced proliferation-associated 1 (SIPA1)-like 1 (SIPA1L1; also known as SPAR1) has been proposed to regulate synaptic functions that are important in maintaining normal neuronal activities, such as regulating spine growth and synaptic scaling, as a component of the PSD-95/NMDA-R-complex. However, its physiological role remains poorly understood. Here, we performed expression analyses using super-resolution microscopy (SRM) in mouse brain and demonstrated that SIPA1L1 is mainly localized to general submembranous regions in neurons, but surprisingly, not to PSD. Our screening for physiological interactors of SIPA1L1 in mouse brain identified spinophilin and neurabin-1, regulators of G-protein-coupled receptor (GPCR) signaling, but rejected PSD-95/NMDA-R-complex components. Furthermore, Sipa1l1-/- mice showed normal spine size distribution and NMDA-R-dependent synaptic plasticity. Nevertheless, Sipa1l1-/- mice showed aberrant responses to α2-adrenergic receptor (a spinophilin target) or adenosine A1 receptor (a neurabin-1 target) agonist stimulation, and striking behavioral anomalies, such as hyperactivity, enhanced anxiety, learning impairments, social interaction deficits, and enhanced epileptic seizure susceptibility. Male mice were used for all experiments. Our findings revealed unexpected properties of SIPA1L1, suggesting a possible association of SIPA1L1 deficiency with neuropsychiatric disorders related to dysregulated GPCR signaling, such as epilepsy, attention deficit hyperactivity disorder (ADHD), autism, or fragile X syndrome (FXS).SIGNIFICANCE STATEMENT Signal-induced proliferation-associated 1 (SIPA1)-like 1 (SIPA1L1) is thought to regulate essential synaptic functions as a component of the PSD-95/NMDA-R-complex. In our screening for physiological SIPA1L1-interactors, we identified G-protein-coupled receptor (GPCR)-signaling regulators. Moreover, SIPA1L1 knock-out (KO) mice showed striking behavioral anomalies, which may be relevant to GPCR signaling. Our findings revealed an unexpected role of SIPA1L1, which may open new avenues for research on neuropsychiatric disorders that involve dysregulated GPCR signaling. Another important aspect of this paper is that we showed effective methods for checking PSD association and identifying native protein interactors that are difficult to solubilize. These results may serve as a caution for future claims about interacting proteins and PSD proteins, which could eventually save time and resources for researchers and avoid confusion in the field.

Metformin directly binds the alarmin HMGB1 and inhibits its proinflammatory activity.

Metformin is the first-line drug in the treatment of type 2 diabetes. In addition to its hypoglycemic effect, metformin has an anti-inflammatory function, but the precise mechanism promoting this activity remains unclear. High mobility group box 1 (HMGB1) is an alarmin that is released from necrotic cells and induces inflammatory responses by its cytokine-like activity and is, therefore, a target of anti-inflammatory therapies. Here we identified HMGB1 as a novel metformin-binding protein by affinity purification using a biotinylated metformin analogue. Metformin directly bound to the C-terminal acidic tail of HMGB1. Both in vitro and in vivo, metformin inhibited inflammatory responses induced by full-length HMGB1 but not by HMGB1 lacking the acidic tail. In an acetaminophen-induced acute liver injury model in which HMGB1 released from injured cells exacerbates the initial injury, metformin effectively reduced liver injury and had no additional inhibitory effects when the extracellular HMGB1 was blocked by anti-HMGB1-neutralizing antibody. In summary, we report for the first time that metformin suppresses inflammation by inhibiting the extracellular activity of HMGB1. Because HMGB1 plays a major role in inflammation, our results suggest possible new ways to manage HMGB1-induced inflammation.

Prostaglandin E2 inhibits neutrophil extracellular trap formation through production of cyclic AMP.

BACKGROUND AND PURPOSE: Upon stimulation, neutrophils release their nuclear contents called neutrophil extracellular traps (NETs), which contain unfolded chromatin and lysosomal enzymes. NETs have been demonstrated to play a critical role in host defence, although the role of PGE2 , a bioactive substance generated in inflammatory tissues, in the formation of NETs remains unclear. EXPERIMENTAL APPROACH: The effects of PGE2 , agonists and antagonists of its receptors, and modulators of the cAMP-PKA pathway on the formation of NETs were examined in vitro in isolated neutrophils and in vivo in a newly established mouse model. KEY RESULTS: PGE2 inhibited PMA-induced NET formation in vitro through EP2 and EP4 Gαs-coupled receptors. Incubation with a cell-permeable cAMP analogue, dibutyryl cAMP, or various inhibitors of a cAMP-degrading enzyme, PDE, also suppressed NET formation. In the assay established here, where an agarose gel was s.c. implanted in mice and NET formation was detected on the surface of the gel, the extent of the NET formed was inhibited in agarose gels containing rolipram, a PDE4 inhibitor, and butaprost, an EP2 receptor agonist. CONCLUSIONS AND IMPLICATIONS: PGE2 inhibits NET formation through the production of cAMP. These findings will contribute to the development of novel treatments for NETosis-related diseases.

Effects of ipsilateral cerebellum ablation on acquisition and retention of classically conditioned eyeblink responses in rats.

The ipsilateral cerebellum to the trained eye has been reported to be essential for acquisition and retention of the conditioned response (CR) in rabbit eyeblink conditioning. Although pharmacological studies have suggested its important roles in other species too, to what degree does eyeblink conditioning in rats depend on the ipsilateral cerebellum is not clear. In this work, we ablated the ipsilateral cerebellum in rats before or after conditioning to examine its roles in acquisition and retention of the CR. In the first experiment, rats received ablation of the ipsilateral cerebellum and recovered for more than 3 weeks. They then underwent eyeblink conditioning for 7 days with a tone and a periorbital electrical shock. Consistent with other previous reports, hemicerebellectomized rats showed significant impairment compared to sham-lesioned rats. However, the hemicerebellectomized rats acquired CRs to some degree, and the acquired CR showed adaptive timing. In the second experiment, rats received the hemicerebellectomy after acquiring CR by 7 days of conditioning in a delay paradigm. After more than 3 weeks of recovery, they were again conditioned in a delay paradigm. Rats with ipsilateral cerebellar lesions showed severe impairment in retention of the pre-acquired CR; however, they reacquired CR to some degree during the subsequent reconditioning sessions. These results suggest that the ipsilateral cerebellum plays an important role in rat eyeblink conditioning as well but that other brain regions can partially compensate for its removal.

[Acute monoblastic leukemia with tetrasomy 8].

Tetrasomy 8 is a rare chromosomal abnormality in acute leukemia, and it has recently been considered as a poor prognostic factor. A 20-year-old woman was admitted because of purpura on the upper and lower limbs in February 2002. On admission, her leukocyte count was 6.5 x 10(9)/l with 66% of blasts, the hemoglobin level was 11.2 g/dl, and the platelet count was 101 x 10(9)/l. The bone marrow aspirate contained 85.6% of peroxidase-negative, alpha-naphthyl-butyrate esterase-positive, and CD4+ CD56+ blast cells. Karyotypic analysis of the bone marrow cells showed 48, XY, + 8, + 8[17]/47, XY, +8[3]. The patient was diagnosed as having AML (M5a), and treatment with daunorubicin (70 mg x 5 days) and cytosine arabinoside (150 mg x 7 days) resulted in a complete remission. She relapsed four months later, however, with an extramedullary tumor in T12. Remission could not be achieved, and the patient underwent allogeneic peripheral blood stem cell transplantation from her HLA-identical mother. Her clinical course was almost uneventful except for a phlegmon in the right leg, but on day 49 a relapse occurred, and she died of acute renal failure on day 73. This case strongly illustrates the characteristic of tetrasomy 8 as a poor prognostic factor in acute leukemia.

[Non-myeloablative stem cell transplantation from an HLA identical sibling donor in a case of treatment-related acute myelogenous leukemia].

A 50-year-old man was admitted to our hospital because of thrombocytopenia during a follow up study of diffuse large B-cell lymphoma in second complete remission. He was diagnosed as having therapy-related acute myelgenous leukemia (t-AML) on the basis of the bone marrow findings and his chemotherapeutic agent history including alkylating agents. Complete remission was achieved by induction chemotherapy. Although allogeneic stem cell transplantation was thought to be needed, the patient was thought to be ineligible for any myeloablative conditioning regimen because of his age and the history of long term chemoradiotherapy. A non-myeloblative regimen was thus selected. After preconditioning with fludarabine, cyclophosphamide and cytarabine, the patient underwent peripheral blood stem cell transplantation from an HLA identical sibling donor. Complete donor chimeras were obtained on day 28 after transplantation. Regimen related toxicities over grade 2 were not observed. Although he suffered from mild chronic graft-versus-host disease(GVHD), he is in good condition without any signs of relapse during a follow-up period of 33 months. It is suggested that non-myeloablative transplantation is feasible and benefical for patients with t-AML who are often ineligible for myeloablative transplants because of their histories of long term chemoradiotherapies.