Changes in Ucp1, D2 (Dio2) and Glut4 (Slc2a4) mRNA expression in response to short-term cold exposure in the house musk shrew (Suncus murinus)

Implantation of engineered adipocytes that outcompete tumors for resources suppresses cancer progression

Tumors acquire an increased ability to obtain and metabolize nutrients. Here, we engineered and implanted adipocytes to outcompete tumors for nutrients and show that they can substantially reduce cancer progression. Growing cells or xenografts from several cancers (breast, colon, pancreas, prostate) alongside engineered human adipocytes or adipose organoids significantly suppresses cancer progression and reduces hypoxia and angiogenesis. Transplanting modulated adipocyte organoids in pancreatic or breast cancer mouse models nearby or distal from the tumor significantly suppresses its growth. To further showcase therapeutic potential, we demonstrate that co-culturing tumor organoids derived from human breast cancers with engineered patient-derived adipocytes significantly reduces cancer growth. Combined, our results introduce a novel cancer therapeutic approach, termed adipose modulation transplantation (AMT), that can be utilized for a broad range of cancers.

Hypobaric hypoxia preconditioning protects against hypothalamic neuron apoptosis in heat-exposed rats by reversing hypothalamic overexpression of matrix metalloproteinase-9 and ischemia

Background: Hypoxia-inducible factor-1α (HIF-1α), heat shock protein-72 (HSP-72), hemeoxygenase-1 (HO-1), and matrix metalloproteinase-9 (MMP-9) have been identified as potential therapeutic targets in the brain for cerebral ischemia. To elucidate their underlying mechanisms, we first aimed to ascertain whether these proteins participate in the pathogenesis of heat-induced ischemic damage to the hypothalamus of rats. Second, we investigated whether hypobaric hypoxia preconditioning (HHP) attenuates heat-induced hypothalamic ischemic/hypoxic injury by modulating these proteins in situ. Methods: Anesthetized rats treated with or without HHP were subjected to heat stress. Hypothalamic ischemic/hypoxic damage was evaluated by measuring hypothalamic levels of cerebral blood flow (CBF), partial oxygen pressure (PO2), and hypothalamic temperature via an implanted probe. Hypothalamic apoptotic neurons were counted by measuring the number of NeuN/caspase-3/DAPI triple-stained cells. Hypothalamic protein expression of HIF-1α, HSP-72, HO-1, and MMP-9 was determined biochemically. Results: Before the start of the thermal experiments, rats were subjected to 5 hours of HHP (0.66 ATA or 18.3% O2) daily for 5 consecutive days per week for 2 weeks, which led to significant loss of body weight, reduced brown adipose tissue (BAT) wet weight and decreased body temperature. The animals were then subjected to thermal studies. Twenty minutes after heat stress, heat-exposed rats not treated with HHP displayed significantly higher core and hypothalamic temperatures, hypothalamic MMP-9 levels, and numbers of hypothalamic apoptotic neurons but significantly lower mean blood pressure, hypothalamic blood flow, and PO2 values than control rats not exposed to heat. In heat-exposed rats, HHP significantly increased the hypothalamic levels of HIF-1α, HSP-72, and HO-1 but significantly alleviated body and hypothalamic hyperthermia, hypotension, hypothalamic ischemia, hypoxia, neuronal apoptosis and degeneration. Conclusions: HHP may protect against hypothalamic ischemic/hypoxic injury and overexpression of MMP-9 by upregulating the hypothalamic expression of HIF-1α, HSP-72, and HO-1 in rats subjected to heatstroke.

Molecular identification, characterization, and structure analysis of house musk shrew (Suncus murinus) leptin

Objective:

House musk shrew (Suncus murinus), a small experimental animal with low body fat, may be a possible model for human lipodystrophy. Leptin is an adipocyte-derived hormone thought to have an important role in the pathophysiology of lipodystrophy. The objectives of this study were to clarify the structure and distribution of suncus leptin.

Materials and methods:

To determine the primary structure of suncus leptin, we cloned the suncus Lep cDNA using the rapid amplification of cDNA ends method. The obtained amino acid (aa) sequence was compared with other mammals and the protein structure prediction was performed.

Results:

The suncus Lep cDNA encodes 170 aa. The putative suncus leptin precursor has a predicted signal peptide of 21 aa, and the mature leptin comprises 149 aa. The mature leptin is 75%–82% homologous to that of other species. Insertion of the three aa, VPQ, not seen in other mammals was found. This VPQ insertion is thought to be due to a nucleotide insertion of nine bases by slippage-like microindels. The predicted 3D structure of suncus leptin exhibited a typical four a-helix structure, however, the VPQ region protruded compared with human leptin. Lep mRNA expression was observed only in white and brown adipose tissues.

Conclusion:

This study revealed the structure and distribution of suncus leptin. Because the addition of VPQ, which is not found in other mammals, was observed, suncus leptin attracts attention to its physiological action, and to the possibility of being a model of human lipodystrophy.

[Dapagliflozin, a Sodium-Glucose Co-transporter-2 Inhibitor, Acutely Reduces Energy Expenditure in Brown Adipose Tissue via Neural Signals in Mice]

　Selective sodium glucose transporter-2 inhibitor (SGLT2i) treatment promotes urinary glucose excretion, thereby reducing blood glucose as well as body weight. However, only limited body weight reductions are achieved with SGLT2i administration. Hyperphagia is reportedly one of the causes of this limited weight loss. However, the effects of SGLT2i on systemic energy expenditure have not been fully elucidated. We investigated the acute effects of dapagliflozin, an SGLT2i, on systemic energy expenditure in mice. Eighteen hours after dapagliflozin administration, oxygen consumption and brown adipose tissue (BAT) expression of ucp1, a thermogenesis-related gene, were significantly decreased as compared with those after vehicle administration. In addition, dapagliflozin significantly suppressed norepinephrine (NE) turnover in BAT and c-fos expression in the rostral raphe pallidus nucleus (rRPa), which contains the sympathetic premotor neurons responsible for thermogenesis. These findings indicate that the dapagliflozin-mediated acute decrease in energy expenditure involves a reduction in BAT thermogenesis via decreased sympathetic nerve activity from the rRPa. Furthermore, common hepatic branch vagotomy abolished the reductions in ucp1 expression, NE contents in BAT, and c-fos expression in the rRPa. In addition, alterations in hepatic carbohydrate metabolism, such as decreases in glycogen contents and upregulation of phosphoenolpyruvate carboxykinase, occurred prior to the suppression of BAT thermogenesis, e.g., 6 h after dapagliflozin treatment. Collectively, these results suggest that SGLT2i acutely suppresses energy expenditure in BAT via regulation of an interorgan neural network consisting of the common hepatic vagal branch and sympathetic nerves.

R-α lipoic acid γ-cyclodextrin complex increases energy expenditure: a 4-month feeding study in mice

OBJECTIVE

A high-fat diet (HFD) affects energy expenditure in laboratory rodents. R-α lipoic acid cyclodextrin (RALA-CD) complex is a stable form of lipoic acid (LA) and may improve energy expenditure. The aim of this study was to determine the effect of RALA-CD on energy expenditure and underlying molecular targets in female laboratory mice.

METHODS

Female C57BL/6J mice were fed a HFD containing 0.1% LA for about 16 wk. The effects on energy expenditure, gene and protein expression were assessed using indirect calorimetry, real-time reverse transcriptase polymerase chain reaction, and Western blot, respectively.

RESULTS

Supplementing mice with RALA-CD resulted in a significant increase in energy expenditure. However, both RALA per se (without γ-cyclodextrin) and S-α lipoic acid cyclodextrin did not significantly alter energy expenditure. Furthermore RALA-CD changed expression of genes encoding proteins centrally involved in energy metabolism. Transcriptional key regulators sirtuin 3 and peroxisome proliferator-activated receptor-γ, coactivator 1 alpha, as well as thyroid related enzyme type 2 iodothyronine deiodinase were up-regulated in brown adipose tissue (BAT) of RALA-CD-fed mice. Importantly, mRNA and/or protein expression of downstream effectors uncoupling protein (Ucp) 1 and 3 also were elevated in BAT from RALA-CD-supplemented mice.

CONCLUSION

Overall, present data suggest that RALA-CD is a regulator of energy expenditure in laboratory mice.

Brown adipose tissue: is it affected by intermittent hypoxia?

Background

Intermittent hypoxia (IH), a model of sleep apnea, produces weight loss in animals. We hypothesized that changes in brown adipose tissue (BAT) function are involved in such phenomenon. We investigated the effect of IH, during 35 days, on body weight, brown adipose tissue wet weight (BATww) and total protein concentration (TPC) of BAT.

Methods

We exposed Balb/c mice to 35 days of IH (n = 12) or sham intermittent hypoxia (SIH; n = 12), alternating 30 seconds of progressive hypoxia to a nadir of 6%, followed by 30 seconds of normoxia. During 8 hours, the rodents underwent a total of 480 cycles of hypoxia/reoxygenation, equivalent to an apnea index of 60/hour. BAT was dissected and weighed while wet. Protein was measured using the Lowry protein assay.

Results

Body weight was significantly reduced in animals exposed to IH, at day 35, from 24.4 ± 3.3 to 20.2 ± 2.2 g (p = 0.0004), while in the SIH group it increased from 23.3 ± 3.81 to 24.1 ± 2.96 g (p = 0.23). BATww was also lower in IH than in SIH group (p = 0.00003). TPC of BAT, however, was similar in IH (204.4 ± 44.3 μg/100 μL) and SIH groups (213.2 ± 78.7 μg/100 μL; p = 0.74) and correlated neither with body weight nor with BATww. TPC appeared to be unaffected by exposure to IH also in multivariate analysis, adjusting for body weight and BATww. The correlation between body weight and BATww is significant (rho= 0.63) for the whole sample. When IH and SIH groups are tested separately, the correlations are no longer significant (rho= 0.48 and 0.05, respectively).

Conclusion

IH during 35 days in a mice model of sleep apnea causes weight loss, BATww reduction, and no change in TPC of BATww. The mechanisms of weight loss under IH demands further investigation.