BACKGROUND: Postpartum depression (PPD) is a serious psychiatric disorder that has significantly adverse impacts on maternal health. Metabolic abnormalities in the brain are associated with numerous neurological disorders, yet the specific metabolic signaling pathways and brain regions involved in PPD remain unelucidated.
METHODS: We performed behavioral test in the virgin and postpartum mice. We used mass spectrometry imaging (MSI) and targeted metabolomics analyses to investigate the metabolic alternation in the brain of GABAAR Delta-subunit-deficient (Gabrd-/-) postpartum mice, a specific preclinical animal model of PPD. Next, we performed mechanism studies including qPCR, Western blot, immunofluorescence staining, electron microscopy and primary astrocyte culture. In the specific knockdown and rescue experiments, we injected the adeno-associated virus into the central amygdala (CeA) of female mice.
RESULTS: We identified that prostaglandin D2 (PGD2) downregulation in the CeA was the most outstanding alternation in PPD, and then validated that lipocalin-type prostaglandin D synthase (L-PGDS)/PGD2 downregulation plays a causal role in depressive behaviors derived from PPD in both wild-type and Gabrd-/- mice. Furthermore, we verified that L-PGDS/PGD2 signaling dysfunction-induced astrocytes atrophy is mediated by Src phosphorylation both in vitro and in vivo.
CONCLUSIONS: L-PGDS/PGD2 signaling dysfunction may be only responsible for the depressive behavior rather than maternal behaviors in the PPD, and it remains to be seen whether this mechanism is applicable to all depression types.
CONCLUSIONS: Our study identified abnormalities in the L-PGDS/PGD2 signaling in the CeA, which inhibited Src phosphorylation and induced astrocyte atrophy, ultimately resulting in the development of PPD in mice.

The function of diverse ruminal microbes is tightly linked to rumen development and host physiology. The system of ruminal microbes is an excellent model to clarify the fundamental ecological relationships among complex nutrient-microbiome-host interactions. Here, neonatal lambs are introduced to different dietary regimes to investigate the influences of early-life crosstalk between nutrients and microbiome on rumen development.
We find starchy corn-soybean starter-fed lambs exhibit the thickest ruminal epithelia and fiber-rich alfalfa hay-fed lambs have the thickest rumen muscle. Metabolome and metagenome data reveal that indole-3-carboxaldehyde (3-IAld) and prostaglandin D2 (PGD2) are the top characteristic ruminal metabolites associated with ruminal epithelial and muscular development, which depend on the enhanced ruminal microbial synthesis potential of 3-IAld and PGD2. Moreover, microbial culture experiment first demonstrates that Bifidobacterium pseudolongum is able to convert tryptophan into 3-IAld and Candida albicans is a key producer for PGD2. Transcriptome sequencing of the ruminal epithelia and smooth muscle shows that ruminal epithelial and muscular development is accompanied by Wnt and Ca2+ signaling pathway activation. Primary cell cultures further confirm that 3-IAld promotes ruminal epithelial cell proliferation depending on AhR-wnt/β-catenin signaling pathway and PGD2 accelerates ruminal smooth muscle cell proliferation via Ca2+ signaling pathway. Furthermore, we find that 3-IAld and PGD2 infusion promote ruminal epithelial and musculature development in lambs.
This study demonstrates that early-life ruminal microbiome-derived 3-IAld and PGD2 are effective promoters of rumen development, which enhances our understanding of nutrient-microbiome-host interactions in early life.

Most animals require sleep, and sleep loss induces serious pathophysiological consequences, including death. Previous experimental approaches for investigating sleep impacts in mice have been unable to persistently deprive animals of both rapid eye movement sleep (REMS) and non-rapid eye movement sleep (NREMS). Here, we report a \"curling prevention by water\" paradigm wherein mice remain awake 96% of the time. After 4 days of exposure, mice exhibit severe inflammation, and approximately 80% die. Sleep deprivation increases levels of prostaglandin D2 (PGD2) in the brain, and we found that elevated PGD2 efflux across the blood-brain-barrier-mediated by ATP-binding cassette subfamily C4 transporter-induces both accumulation of circulating neutrophils and a cytokine-storm-like syndrome. Experimental disruption of the PGD2/DP1 axis dramatically reduced sleep-deprivation-induced inflammation. Thus, our study reveals that sleep-related changes in PGD2 in the central nervous system drive profound pathological consequences in the peripheral immune system.

OBJECTIVE: To explore the mechanism of moxibustion in the treatment of asthmatic inflammation from the point of short-chain fatty acids (SCFAs) in rats with asthma.
METHODS: A total of 48 SD rats (half male and half female) were randomly divided into 4 groups： normal, model, lung treatment and joint-treatment of lung and intestine (joint-treatment), with 12 rats in each group. The asthma model was made by subcutaneous (bilateral back and inguinal regions) and intraperitoneal injection of mixture solution of ovalbumin and aluminium hydroxide gel (on day 1 and 8) and followed by inhalation of atomized 1% ovalbumin (20 min from day 15, once daily for one week). Moxibustion was applied to bilateral \"Feishu\" (BL13) for rats of the lung treatment group or bilateral \"Feishu\" (BL13) and \"Tianshu\" (ST25) for rats of the joint treatment group. One hour after the intervention, the rats in the later three groups were separately given atomized 1% ovalbumin solution inhalation for 20 min. The treatment was conducted for 30 min, once daily for 14 consecutive days. At the end of the intervention, the percentage of inflammatory cells in blood was detected by biochemical method and histopathological changes of the lung were observed after H.E. staining. The inflammatory cells in the bronchoalveolar lavage fluid (BALF) were counted after Wright-Giemsa staining. The mRNA expressions of interleukin (IL)-4, IL-5, IL-13, IL-17, IL-33, leukotriene (LT), thymic stromal lymphopoietin (TSLP) and prostaglandin D2 (PGD2) were detected by real-time PCR, and the contents of SCFAs in rats\' feces were detected by gas chromatography-mass spectrometry.
RESULTS: Relevant to the normal group, the model group had an obvious increase in the percentages of neutrophils, lymphocytes and eosinophils in the blood, the percentages of neutrophils and eosinophils in the BALF, and in the expression levels of PGD2, TSLP, LT, IL-4, IL-5, IL-13, IL-17 and IL-33 mRNAs in the lung tissues (P<0.01, P<0.05), and a marked decrease in the contents of acetic acid, propionic acid, isobutyric acid, butyric acid and valeric acid in feces (P<0.05, P<0.01). After the treatment, the percentages of neutrophils and lymphocytes in the peripheral blood, eosinophils in the BALF, and the expression levels of PGD2, TSLP, LT, IL-4, IL-17, IL-33 mRNAs in the lung tissues in both the lung treatment and joint treatment groups, as well as neutrophils of BALF, and expression of IL-5 and IL-13 mRNAs in the joint treatment group were significantly down-regulated (P<0.01, P<0.05), while the contents of acetic acid, propionic acid and valerate in the lung treatment group, and acetic acid, propionic acid, isobutyric acid, butyric acid and valeric acid in the joint treatment group were all strikingly increased (P<0.05, P<0.01). The effect of the joint treatment was superior to that of lung treatment in down-regulating the expressions of LT and IL-5 mRNAs (P<0.05, P<0.01) and up-requlating the content of propionic acid (P<0.05). Results of H.E. staining showed thickened alveolar wall, infiltration of a large number of inflammatory cells and interstitial fibrous tissue hyperplasia around the bronchus and scattered arrangement of cells of the lung tissue in the model group, which was relatively milder in both lung treatment and joint treatment groups, particularly the later.
CONCLUSIONS: Joint treatment of asthma from the lung and intestine can better regulate the contents of intestinal SCFAs and alleviate the inflammatory response of asthmatic model rats, thus, intestinal SCFAs may be involved in the process of moxibustion in improving inflammatory response.
目的：从对肠道短链脂肪酸（SCFAs）的调控角度探讨艾灸改善哮喘炎性反应的可能作用机制。方法：48只SD大鼠随机分为正常组、模型组、从肺论治组和肺肠同治组，每组12只。采用卵清白蛋白（OVA）致敏和雾化激发法制备哮喘大鼠模型。从肺论治组艾灸大鼠双侧“肺俞”30 min；肺肠同治组艾灸大鼠双侧“肺俞”“天枢”共30 min。模型组、从肺论治组、肺肠同治组大鼠上述干预结束1 h后，分别予以1% OVA溶液雾化20 min，均每天1次，连续14 d。同血细胞分析仪检测外周血中炎性细胞百分比，HE染色法观察肺组织病理形态学改变，瑞氏-吉姆萨染色法计数肺泡灌洗液（BALF）中炎性细胞，实时荧光定量PCR法检测肺组织中白细胞介素（IL）-4、IL-5、IL-13、IL-17、IL-33、前列腺素D2（PGD2）、胸腺基质淋巴细胞生成素（TSLP）和白三烯（LT） mRNA的表达，气相色谱-质谱联用法检测粪便中SCFAs的含量。结果：与正常组相比，模型组大鼠肺组织结构重度异常，肺泡壁增厚，支气管周围可见大量炎性细胞浸润；外周血中性粒细胞、淋巴细胞、嗜酸性粒细胞百分比，BALF中嗜酸性粒细胞、中性粒细胞百分比，肺组织中IL-4、IL-5、IL-13、IL-17、IL-33、PGD2、TSLP、LT的mRNA表达均显著升高（P<0.01，P<0.05）；粪便中乙酸、丙酸、异丁酸、丁酸、戊酸的含量均显著降低（P<0.05，P<0.01）。与模型组相比，从肺论治组和肺肠同治组大鼠肺组织病理形态学损伤均显著改善；外周血中性粒细胞和淋巴细胞百分比，BALF中嗜酸性粒细胞百分比，肺组织中IL-4、IL-17、IL-33、PGD2、TSLP、LT的mRNA表达均显著降低（P<0.01，P<0.05）；粪便中乙酸、丙酸、戊酸的含量均显著升高（P<0.05，P<0.01）。除此之外，与模型组相比，肺肠同治组大鼠BALF中中性粒细胞百分比，肺组织中IL-5、IL-13的mRNA表达也均显著降低（P<0.05，P<0.01），粪便中异丁酸、丁酸含量也均显著升高（P<0.05，P<0.01）。与从肺论治组相比，肺肠同治组大鼠肺组织中IL-5、LT的mRNA表达均显著降低（P<0.01，P<0.05），粪便中丙酸含量显著升高（P<0.05）。结论：艾灸“肺肠同治”可以更好地调节肠道SCFAs的含量，缓解哮喘模型大鼠炎性反应；肠道SCFAs可能参与了艾灸改善哮喘大鼠炎性反应的作用过程。.

OBJECTIVE: Secreted phospholipase A2 Group IB (sPLA2GIB) regulates the release of arachidonic acid, prostaglandins, and other inflammatory lipid mediators. Although it has been well involved in extensive inflammatory diseases, its specific mechanism in chronic rhinosinusitis with nasal polyps (CRSwNP) remains unclear. In this study, we investigated the role of sPLA2GIB in the pathophysiology of CRSwNP.
METHODS: Quantitative PCR, immunofluorescence staining, western blotting, and enzyme-linked immunosorbent assay (ELISA) were used to analyze the expression of sPLA2s, phospholipase A2 receptor (PLA2R), and prostaglandin D2 (PGD2) in nasal samples. Human nasal epithelial cells (HNECs) were cultured at an air-liquid interface (ALI) and stimulated with various cytokines. The human mast cell line HMC-1 was stimulated with sPLA2GIB, and the expression of PGD2 and cytokines in the culture supernatant was detected by ELISA.
RESULTS: The mRNA and protein levels of sPLA2GIB were significantly higher in eosinophilic CRSwNP than in control tissues. sPLA2GIB was predominantly expressed in the nasal epithelial cells. PLA2R mRNA and protein levels were upregulated in both eosinophilic and non-eosinophilic CRSwNP compared with the control groups. IL-4, IL-13, TNF-α, and IL-1β upregulated the expression of sPLA2GIB in ALI-cultured HNECs. sPLA2GIB induced PGD2 and IL-13 production in HMC-1 cells in a hydrolytic activity-independent manner. PGD2 protein expression was elevated in tissue homogenates of eosinophilic CRSwNP, and PGD2 upregulated the expression of IL-13 in HMC-1 cells.
CONCLUSIONS: Increased secretion of sPLA2GIB by epithelial cells may promote eosinophilic inflammation in CRSwNP by enhancing PGD2 and IL-13 production in mast cells via binding to PLA2R.
METHODS: N/A Laryngoscope, 134:1107-1117, 2024.

Prostaglandin (PG) D2, a commonly considered vasodilator through D prostanoid receptor-1 (DP1), might also evoke vasoconstriction via acting on the thromboxane (Tx)-prostanoid receptor (the original receptor of TxA2; TP) and/or E prostanoid receptor-3 (one of the vasoconstrictor receptors of PGE2; EP3). This study aimed to test the above hypothesis in the mouse renal vascular bed (main renal arteries and perfused kidneys) and/or mesenteric resistance arteries and determine how the vasoconstrictor mechanism influences the overall PGD2 effect on systemic blood pressure under in vivo conditions. Experiments were performed on control wild-type (WT) mice and mice with deficiencies in TP (TP-/-) and/or EP3 (EP3-/-). Here we show that PGD2 indeed evoked vasoconstrictor responses in the above-mentioned tissues of WT mice, which were however not only reduced by TP-/- or EP3-/-, but also reversed by TP-/-/EP3-/- in some of the above tissues (mesenteric resistance arteries or perfused kidneys) to dilator reactions that were reduced by non-selective DP antagonism. A slight or mild pressor response was also observed with PGD2 under in vivo conditions, and this was again reversed to a depressor response in TP-/- or TP-/-/EP3-/- mice. Non-selective DP antagonism reduced the PGD2-evoked depressor response in TP-/-/EP3-/- mice as well. These results thus demonstrate that like other PGs, PGD2 activates TP and/or EP3 to evoke vasoconstrictor activities, which can outweigh its concurrent vasodepressor activity mediated mainly through DP1, and hence result in a pressor response, although the response might only be of a slight or mild extent.

BACKGROUND: Prostaglandin D2 (PGD2) has been shown to restrict the occurrence and development of multiple cancers; nevertheless, its underlying molecular mechanism has not been fully elucidated. The present study investigated the effect of PGD2 on the biological function of the enriched gastric cancer stem cells (GCSCs), as well as its underlying molecular mechanism, to provide a theoretical basis and potential therapeutic drugs for gastric cancer (GC) treatment.
METHODS: The plasma PGD2 levels were detected by Enzyme-linked immunosorbent assay (ELISA). Silencing of lipocalin prostaglandin D synthetases (L-PTGDS) and prostaglandin D2 receptor 2 (PTGDR2) was carried out in GCSCs from SGC-7901 and HGC-27 cell lines. Cell Counting Kit-8, transwell, flow cytometry, and western blotting assays were used to determine cell viability, invasion, apoptosis, and stemness of GCSCs. In vivo xenograft models were used to assess tumor growth.
RESULTS: Clinically, it was found that the plasma PGD2 level decreased significantly in patients with GC. PGD2 suppressed viability, invasion, and stemness and increased the apoptosis of GCSCs. Downregulating L-PTGDS and PTGDR2 promoted viability, invasion, and stemness and reduced the apoptosis of GCSCs. Moreover, the inhibition of GCSCs induced by PGD2 was eliminated by downregulating the expression of PTGDR2. The results of in vivo experiments were consistent with those of in vitro experiments.
CONCLUSIONS: Our data suggest that PGD2 may be an important marker and potential therapeutic target in the clinical management of GC. L-PTGDS/PTGDR2 may be one of the critical targets for GC therapy. The PGD2/PTGDR2 signal affects the viability, invasion, apoptosis, and stemness of GCSCs and prevents the progression of GC.

15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) exhibited potential to alleviate liver inflammation in chronic injury but was less studied in acute injury. Acute liver injury was associated with elevated macrophage migration inhibitory factor (MIF) levels in damaged hepatocytes. This study aimed to investigate the regulatory mechanism of hepatocyte-derived MIF by 15d-PGJ2 and its subsequent impact on acute liver injury. In vivo, mouse models were established by carbon tetrachloride (CCl4) intraperitoneal injection, with or without 15d-PGJ2 administration. 15d-PGJ2 treatment reduced the necrotic areas induced by CCl4. In the same mouse model constructed using enhanced green fluorescent protein (EGFP)-labeled bone marrow (BM) chimeric mice, 15d-PGJ2 reduced CCl4 induced BM-derived macrophage (BMM, EGFP+F4/80+) infiltration and inflammatory cytokine expression. Additionally, 15d-PGJ2 down-regulated liver and serum MIF levels; liver MIF expression was positively correlated with BMM percentage and inflammatory cytokine expression. In vitro, 15d-PGJ2 inhibited Mif expression in hepatocytes. In primary hepatocytes, reactive oxygen species inhibitor (NAC) showed no effect on MIF inhibition by 15d-PGJ2; PPARγ inhibitor (GW9662) abolished 15d-PGJ2 suppressed MIF expression and antagonists (troglitazone, ciglitazone) mimicked its function. In Pparg silenced AML12 cells, the suppression of MIF by 15d-PGJ2 was weakened; 15d-PGJ2 promoted PPARγ activation in AML 12 cells and primary hepatocytes. Furthermore, the conditioned medium of recombinant MIF- and lipopolysaccharide-treated AML12 respectively promoted BMM migration and inflammatory cytokine expression. Conditioned medium of 15d-PGJ2- or siMif-treated injured AML12 suppressed these effects. Collectively, 15d-PGJ2 activated PPARγ to suppress MIF expression in injured hepatocytes, reducing BMM infiltration and pro-inflammatory activation, ultimately alleviating acute liver injury.

Tuberculosis caused by Mycobacterium tuberculosis is a leading cause of death globally and a major health concern. In humans, macrophages are the first line invaded by M. tuberculosis. Upon infection, macrophages upregulate cyclooxygenase-2 (COX-2) expression and consequently elevate the formation of PGs, including PGE2 and PGD2. Although the role of proinflammatory PGE2 in M. tuberculosis infection has been reported, the roles of PGJ2 and 15-deoxy-PGJ2 (collectively named J2-PGs), the metabolites of PGD2 with anti-inflammatory features, remain elusive. In this study, we show that M. tuberculosis (H37Rv strain)-conditioned medium stimulates human monocyte-derived macrophages (MDMs) to elevate COX-2 expression along with robust generation of PGJ2, exceeding PGD2 formation, and to a minor extent also of 15-deoxy-PGJ2. Of interest, in M1-MDM phenotypes, PGJ2 and 15-deoxy-PGJ2 decreased M. tuberculosis (H37Rv strain)-conditioned medium-induced COX-2 expression and related PG formation by a negative feedback loop. Moreover, these J2-PGs downregulated the expression of the proinflammatory cytokines IL-6, IL-1β, and IFN-γ, but elevated the anti-inflammatory cytokine IL-10 and the M2 markers arginase-1 and CD163. These anti-inflammatory effects of J2-PGs in M1-MDM correlated with impaired activation of TGF-β-activated kinase 1/NF-κB/MAPK pathways. Finally, we found that J2-PGs regulate COX-2 expression, at least partially, via PGD2 receptor (DP1) and chemoattractant receptor homologue expressed on Th2 cells/DP2 receptors, but independent of the J2-PG receptor peroxisome proliferator-activated receptor-γ. Together, our findings reveal that M. tuberculosis induces COX-2 expression in human M1-MDMs, along with robust formation of J2-PGs that mediates anti-inflammatory effects via a negative feedback loop.

Mammalian skeletal muscles consist of two main fibre types: slow-twitch (type I, oxidative) and fast-twitch (type IIa, fast oxidative; type IIb/IIx, fast glycolytic). Muscle fibre composition switch is closely associated with chronic diseases such as muscle atrophy, obesity, type II diabetes and athletic performance. Prostaglandin D2 (PGD2 ) is a bioactive lipid derived from arachidonic acid that aggravates muscle damage and wasting during muscle atrophy. This study aimed to investigate the precise mechanisms underlying PGD2 -mediated muscle homeostasis and myogenesis.
Skeletal muscle-specific PGD2 receptor DP2-deficient mice (DP2fl/fl HSACre ) and their littermate controls (DP2fl/fl ) were subjected to exhaustive exercise and fed a high-fat diet (HFD). X-linked muscular dystrophy (MDX) mice and HFD-challenged mice were treated with the selective DP2 inhibitor CAY10471. Exercise tolerance, body weight, glycometabolism and skeletal muscle fibre composition were measured to determine the role of the skeletal muscle PGD2 /DP2 signalling axis in obesity and muscle disorders. Multiple genetic and pharmacological approaches were also used to investigate the intracellular signalling cascades underlying the PGD2 /DP2-mediated skeletal muscle fibre transition.
PGD2 generation and DP2 expression were significantly upregulated in the hindlimb muscles of HFD-fed mice (P < 0.05 or P < 0.01 vs. normal chow diet). Compared with DP2fl/fl mice, DP2fl/fl HSACre mice exhibited remarkable glycolytic-to-oxidative fibre-type transition in hindlimb muscles and were fatigue resistant during endurance exercise (154.9 ± 6.0 vs. 124.2 ± 8.1 min, P < 0.05). DP2fl/fl HSACre mice fed an HFD showed less weight gain (P < 0.05) and hepatic lipid accumulation (P < 0.01), reduced insulin resistance and enhanced energy expenditure (P < 0.05) compared with DP2fl/fl mice. Mechanistically, DP2 deletion promoted the nuclear translocation of nuclear factor of activated T cells 1 (NFATc1) by suppressing RhoA/Rho-associated kinase 2 (ROCK2) signalling, which led to enhanced oxidative fibre-specific gene transcription in muscle cells. Treatment with CAY10471 enhanced NFATc1 activity in the skeletal muscles and ameliorated HFD-induced obesity (P < 0.05 vs. saline) and insulin resistance in mice. CAY10471 also enhanced exercise tolerance in MDX mice (100.8 ± 8.0 vs. 68.9 ± 11.1 min, P < 0.05 vs. saline) by increasing the oxidative fibre-type ratio in the muscles (45.1 ± 2.3% vs. 32.3 ± 2.6%, P < 0.05 vs. saline).
DP2 activation suppresses oxidative fibre transition via RhoA/ROCK2/NFATc1 signalling. The inhibition of DP2 may be a potential therapeutic approach against obesity and muscle disorders.