Cyclooxygenase-2 up-regulates hepatic somatostatin receptor 2 expression

Enhanced Detection of Early Pulmonary Fibrosis Disease Using 68Ga-FAPI-LM3 PET

Early detection of pulmonary fibrosis is a critical yet insufficiently met clinical necessity. This study evaluated the effectiveness of FAPI-LM3, a 68Ga-radiolabeled heterobivalent molecular probe that targets fibroblast activating protein (FAP) and somatostatin receptor 2 (SSTR2), in the early detection of pulmonary fibrosis, leveraging its potential for early disease identification. A bleomycin-induced early pulmonary fibrosis model was established in C57BL/6 mice for 7 days. FAP and SSTR2 expression levels were quantitatively assessed in human idiopathic pulmonary fibrosis lung tissue samples and bleomycin-treated mouse lung tissues by using western blotting, real-time quantitative PCR (RT-qPCR), and immunofluorescence techniques. The diagnostic performance of FAPI-LM3 was investigated by synthesizing monomeric radiotracers 68Ga-FAPI-46 and 68Ga-DOTA-LM3 alongside the heterobivalent probe 68Ga-FAPI-LM3. These imaging radiopharmaceuticals were used in small-animal PET to compare their uptake in fibrotic and normal lung tissues. Results indicated significant upregulation of FAP and SSTR2 at both RNA and protein levels in fibrotic lung tissues compared with that in normal controls. PET imaging demonstrated significantly enhanced uptake of the 68Ga-FAPI-LM3 probe in fibrotic lung tissues, with superior visual effects compared to monomeric tracers. At 60 min postinjection, early stage fibrotic tissues (day 7) demonstrated low-to-medium uptake of monomeric probes, including 68Ga-DOTA-LM3 (0.45 ± 0.04% ID/g) and 68Ga-FAPI-46 (0.78 ± 0.09% ID/g), whereas the uptake of the heterobivalent probe 68Ga-FAPI-LM3 (1.90 ± 0.10% ID/g) was significantly higher in fibrotic lesions than in normal lung tissue. Blockade experiments confirmed the specificity of 68Ga-FAPI-LM3 uptake, which was attributed to synergistic targeting of FAP and SSTR2. This study demonstrates the potential of 68Ga-FAPI-LM3 for early pulmonary fibrosis detection via molecular imaging, offering significant benefits over monomeric tracers 68Ga-FAPI-46 and 68Ga-DOTA-LM3. This strategy offers new possibilities for noninvasive and precise early detection of pulmonary fibrosis.

The transcriptomic profile shows the protective effects of celecoxib on cirrhotic splenomegaly

BACKGROUND

Splenomegaly can exacerbate liver cirrhosis and portal hypertension. We have previously demonstrated that cyclooxygenase-2 (COX-2) inhibitor can attenuate cirrhotic splenomegaly. However, the mechanism of cirrhotic splenomegaly remains unclear, thus becoming the focus of the present study.

MATERIALS AND METHODS

Thioacetamide (TAA) intraperitoneal injection was used to induce cirrhotic splenomegaly. Rats were randomized into the control, TAA and TAA + celecoxib groups. Histological analysis and high-throughput RNA sequencing of the spleen were conducted. Splenic collagen III, α-SMA, Ki-67, and VEGF were quantified.

RESULTS

A total of 1461 differentially expressed genes (DEGs) were identified in the spleens of the TAA group compared to the control group. The immune response and immune cell activation might be the major signaling pathways involved in the pathogenesis of cirrhotic splenomegaly. With its immunoregulatory effect, celecoxib presents to ameliorate cirrhotic splenomegaly and liver cirrhosis. Furthermore, 304 coexisting DEGs were obtained between TAA vs. control and TAA + celecoxib vs. TAA. Gene ontology (GO) and KEGG analyses collectively indicated that celecoxib may attenuate cirrhotic splenomegaly through the suppression of splenic immune cell proliferation, inflammation, immune regulation, and fibrogenesis. The impacts on these factors were subsequently validated by the decreased splenic Ki-67-positive cells, macrophages, fibrotic areas, and mRNA levels of collagen III and α-SMA.

CONCLUSIONS

Celecoxib attenuates cirrhotic splenomegaly by inhibiting splenic immune cell proliferation, inflammation, and fibrogenesis. The current study sheds light on the therapeutic strategy of liver cirrhosis by targeting splenic abnormalities and provides COX-2 inhibitors as a novel medical treatment for cirrhotic splenomegaly.

The Role of Receptor-Ligand Interaction in Somatostatin Signaling Pathways: Implications for Neuroendocrine Tumors

Neuroendocrine tumors (NETs) arise from neuroendocrine cells and manifest in diverse organs. Key players in their regulation are somatostatin and its receptors (SSTR1-SSTR5). Understanding receptor-ligand interactions and signaling pathways is vital for elucidating their role in tumor development and therapeutic potential. This review highlights SSTR characteristics, localization, and expression in tissues, impacting physiological functions. Mechanisms of somatostatin and synthetic analogue binding to SSTRs, their selectivity, and their affinity were analyzed. Upon activation, somatostatin initiates intricate intracellular signaling, involving cAMP, PLC, and MAP kinases and influencing growth, differentiation, survival, and hormone secretion in NETs. This review explores SSTR expression in different tumor types, examining receptor activation effects on cancer cells. SSTRs' significance as therapeutic targets is discussed. Additionally, somatostatin and analogues' role in hormone secretion regulation, tumor growth, and survival is emphasized, presenting relevant therapeutic examples. In conclusion, this review advances the knowledge of receptor-ligand interactions and signaling pathways in somatostatin receptors, with potential for improved neuroendocrine tumor treatments.

Exploration on the Effect of Nonselective β-Receptor Blockers (NSBBs) on Hemodynamic Parameters in Complicated Liver Cirrhosis

Esophageal-gastric variceal bleeding occurs in 5–15% of patients with liver cirrhosis annually, and the mortality rate is as high as 20% within 6 weeks of the first bleed. The more compromised the liver function, the higher the mortality. Effective control of bleeding is pivotal for reducing mortality in patients with liver cirrhosis. To explore the effect of nonselective β-receptor blockers (NSBBs) on hemodynamic parameters in liver cirrhosis complicated with esophageal-gastric variceal bleeding and the association with hepatorenal syndrome (HRS), this retrospective study assessed the clinical data of 248 patients with liver cirrhosis and esophageal-gastric variceal hemorrhage admitted to our hospital for research. 112 patients are treated with somatostatin (control group) and 136 with somatostatin+propranolol (study group). The success rate of hemostasis, changes of hemodynamic parameters before and after treatment, and incidence of HRS are compared between the groups. Logistic regression analysis is used to explore the use of propranolol when HRS occurred. NSBBs combined with somatostatin are more effective than somatostatin alone in the treatment of liver cirrhosis complicated with esophageal-gastric variceal bleeding; NSBBs may be associated with the occurrence of HRS.

Celecoxib ameliorates liver cirrhosis via reducing inflammation and oxidative stress along spleen-liver axis in rats

BACKGROUND & AIMS

Splenomegaly is usually taken as a consequence of liver cirrhosis. However, as a risk factor for cirrhosis, the impacts of spleen-liver axis on the development of cirrhosis are largely unknown. This study focused on the impacts of splenomegaly on the development of cirrhosis and assessment of the effects of celecoxib, a selective COX-2 inhibitor, on the splenomegaly and cirrhotic liver.

MATERIALS AND METHODS

Liver cirrhosis was induced by thioacetamide (TAA). Sixty rats were randomly divided into control, TAA-16w, TAA + celecoxib groups and normal, TAA + sham, TAA + splenectomy groups. Hepatic stellate cells (HSCs) or hepatocytes were co-cultured with splenocytes from those groups.

RESULTS

Splenocytes of cirrhotic rats stimulated the HSCs activation and induced hepatocyte apoptosis via enhancing oxidative stress. The hepatic levels of NOX-4 and the in situ O₂^- were profoundly reduced in TAA + splenectomy group by 50.6% and 18.5% respectively, p < 0.05. Celecoxib significantly decreased the hepatic fibrotic septa induced with TAA by 50.8%, p < 0.05. Splenic lymphoid tissue proliferation and proinflammatory cytokines of the cirrhotic rats were also obviously suppressed by celecoxib, p < 0.05. Compared with the HSC or hepatocyte cell line co-cultured with the cirrhotic splenocytes, the expression of alpha-SMA, NOX-4, in situ O₂^- or the levels of cleaved caspase3 and NOX-4 were significantly decreased in those cell lines co-cultured with cirrhotic splenocytes treated by celecoxib, p < 0.05.

CONCLUSION

Splenomegaly contributed to the development of liver cirrhosis through enhancing oxidative stress in liver. Celecoxib could effectively ameliorate liver cirrhosis via reducing inflammatory cytokines and immune cells derived from spleen and suppressing oxidative stress.

COX-2 in liver fibrosis

As a vital inducible sensor, cyclooxygenase-2 (COX-2) plays an important role in the progress of hepatic fibrogenesis. Activation of hepatic stellate cells (HSCs) in the liver can significantly accelerate the onset and development of liver fibrosis. COX-2 overexpression triggers inflammation that is an important inducer in hepatic fibrosis. Increasing evidence indicates that COX-2 is involved in the main pathogenesis of liver fibrosis, such as inflammation, apoptosis, and cell senescence. Moreover, COX-2 expression is altered in patients and animal models with non-alcoholic fatty liver disease or cirrhosis. These findings suggest that COX-2 has a broad and critical role in the development of liver fibrosis. In this review, we summarize the latest advances in the regulation and signal transduction of COX-2 and its impact on liver fibrosis.

Neovascularization is a key feature of liver fibrosis progression: anti-angiogenesis as an innovative way of liver fibrosis treatment

Liver fibrosis affects over 100 million people in the world; it represents a multifactorial, fibro-inflammatory disorder characterized by exacerbated production of extracellular matrix with consequent aberration of hepatic tissue. The aetiology of this disease is very complex and seems to involve a broad spectrum of factors including the lifestyle, environment factors, genes and epigenetic changes. More evidences indicate that angiogenesis, a process consisting in the formation of new blood vessels from pre-existing vessels, plays a crucial role in the progression of liver fibrosis. Central to the pathogenesis of liver fibrosis is the hepatic stellate cells (HSCs) which represent a crossroad among inflammation, fibrosis and angiogenesis. Quiescent HSCs can be stimulated by a host of growth factors, pro-inflammatory mediators produced by damaged resident liver cell types, as well as by hypoxia, contributing to neoangiogenesis, which in turn can be a bridge between acute and chronic inflammation. As matter of fact, studies demonstrated that neutralization of vascular endothelial growth factor as well as other proangiogenic agents can attenuate the progression of liver fibrosis. With this review, our intent is to discuss the cause and the role of angiogenesis in liver fibrosis focusing on the current knowledge about the impact of anti-angiogenetic therapies in this pathology.

CREB family: A significant role in liver fibrosis

Liver fibrosis (LF) is known as a result of the progressive accumulation of extracellular matrix (ECM), and always ascribed to chronic liver diseases. Advanced liver fibrosis results in cirrhosis, liver failure, portal hypertension, and even multi-organ dysfunction and will bring up a health care burden worldwide. Cyclic AMP response-element binding protein (CREB), as a critical transcriptional factor, binds with conserved cAMP response-element (CRE), which is located in the promoter of targeted genes, to regulate the transcription. In the past decades, numerous studies have contributed to improved understanding of the links between CREB and liver fibrosis. In this review, we will summarize molecular mechanisms of CREB pathways and discuss contributions of CREB to liver fibrosis, focusing on activation and proliferation of hepatic stellate cells (HSCs), proliferation of cholangiocytes, deposition of extracellular matrix (ECM) and inflammation, for the development of antifibrotic therapies.