Direct cardiac reprogramming of fibroblasts into induced cardiomyocytes (iCMs) is a promising approach but remains a challenging technology of regenerative medicine for damaged myocardium. Efforts have been focused on improving the efficiency by understanding fundamental mechanisms. One of the major challenges is that the plasticity of cultured fibroblast varies batch to batch with unknown mechanisms. Here, we noticed that a portion of in vitro cultured fibroblasts have been activated to differentiate into myofibroblasts, marked by the expression of αSMA, even in the primary cell culture of tissues. Both forskolin, which activates adenylyl cyclase and increases cAMP concentration, and TGFbeta inhibitor SB431542 can efficiently suppress myofibroblast differentiation of cultured fibroblasts. However, SB431542 improved but forskolin blocked iCM reprogramming of fibroblasts that were infected with retroviruses of Gata4, Mef2c and Tbx5 (GMT). Moreover, inhibitors of cAMP downstream signaling pathways, PKA or CREB-CBP, significantly improved the efficiency of iCM reprogramming. Consistently, inhibition of p38/MAPK, another upstream regulator of CREB-CBP, also improved reprogramming efficiency. We then investigated if inhibition of these signaling pathways in primary cultured fibroblast could improve their plasticity for reprogramming, and found that preconditioning of cultured fibroblasts with CREB-CBP inhibitor significantly improved the cellular plasticity of fibroblasts to be reprogrammed, yielding ~2-fold amount of reprogrammed iCMs compared to that of untreated control cells. In conclusion, suppression of cAMP/PKA/CREB signaling axis improves fibroblast plasticity for direct cardiac reprogramming.

Methamphetamine (METH) has the potential to disrupt the activities of neurotransmitters in the Central Nervous System (CNS) and cause neurotoxicity through various pathways. These pathways include increased production of reactive nitrogen and oxygen species, hypothermia, and induction of mitochondrial apoptosis. In this study, we investigated the long-term effects of METH addiction on the structural changes in the amygdala of postmortem human brains, as well as the involvement of the CREB/BDNF and Akt-1/GSK3 signaling pathways. We examined ten male postmortem brains, comparing control subjects with chronic METH users, using immunohistochemistry, Real-time PCR (to measure levels of CREB, BDNF, Akt-1, GSK3, and TNF-α), Tunnel assay, stereology, and assays for ROS, GSSG, and GPX. The findings revealed that METH significantly reduced the expression of BDNF, CREB, Akt-1, and GPX, while increasing the levels of GSSG, ROS, RIPK3, GSK3, and TNF-α. Furthermore, METH was found to induce inflammation and neurodegeneration in the amygdala, with ROS production mediated by the CREB/BDNF and Akt-1/GSK3 signaling pathways.

Both the use of plastic and its decomposition products lead to the distribution of plastic all over the earth and finally to the uptake by all kind of living beings including humans. Still, it is widely unknown what risks harbor the widespread uptake of plastics for human health, espe-cially regarding contributing factors like size, shape and surface composition. We assessed the uptake of polymethylmethacrylate (PMMA)-nano- and microbeads for HEK293-, A549- and MRC5 cells. Via confocal microscopy, we localized multiple PMMA-beads inside the cytosol of cells. Uptake of PMMA-beads did not alter cell growth and cell division, implying no short-term toxicity towards human cells. Further, we used a cAMP response element binding protein (CREB)-mediated reporter assay to assess whether internalized PMMA-nanobeads alter cell-signaling pathways. In contrast to the in vitro transcription, where the addition of PMMA-nanobeads abolished the transcription, no changes regarding CREB-mediated cell sig-naling are given in HEK293-cells. Our data led to the assumption that PMMA-nano-and mi-crobeads are internalized via endocytosis and end up as lysosomes within the cells cytosol. Therefore, we concluded differences regarding the surface composition of the PMMA-nanobeads mainly affect its potential to alter cell signaling. These findings emphasize the key role the sur-face composition plays regarding microplastic and its risks for human health.

Knee Osteoarthritis (KOA) is a chronic disease characterized by progressive disability and joint pain. Meniscus chondrocytes apoptosis is the main cause of reduced chondrocyte number and self-repair function. The purpose of this study was to investigate the role of miR-27b-3p in KOA.In this study, we found that the expression of miR-27b-3p was downregulated in cultured IL-1β treated chondrocyte and cartilage tissues in KOA. KOA overexpression evidently reduced IL-1β induced chondrocyte apoptosis and caspase-3 and caspase-9 expression.The upregulated iNOS and COX-2 mRNA and proteins expression was also inhibited by miR-27b-3p mimics. The expression of nitric oxide, PGE2, TNF-α and IL-6 was also inhibited by miR-27b-3p mimics. The target gene of miR-27b-3p was confirmed to be BDNF. TrkB/CREB pathway was proved to be the downstream pathway of miR-27b-3p/BDNF axis.The apoptotic cell percentage and nitric oxide, PGE2, TNF-α and IL-6 expression was induced by BDNF+IL-1β. This induction was inhibited by miR-27b-3p mimics. The cartilage tissues stained with safranin O results showed miR-27b-3p greatly decreased KOA induced cartilage degradation. The expression of BDNF、TrkB and p-CREB was inhibited by len-miR-27b-3p. MiR-27b-3p also reduced the expression of TNF-α、IL-6 and Bax, and increased Bcl-2 expression. These results indicated miR-27b-3p could applied to inhibit the development of KOA and miR-27b-3p/BDNF/TrkB/CREB pathway could serve as novel treatment target to handle KOA.

Local cryotherapy is widely used as a treatment for sports-related skeletal muscle injury. However, its molecular mechanisms are unknown. To clarify these mechanisms, in this study, we applied one to three 15-min cold stimulations at 4 °C to various cell lines (in vitro), the tibialis anterior (TA) muscle (ex vivo), and mouse limbs (in vivo). In the in vitro assay, cAMP response element-binding protein 1 (CREB1) was markedly phosphorylated (as pCREB1) and CREB-binding protein (CBP) was recruited to pCREB-1 in response to two or three cold stimulations. In a reporter assay with the cAMP-responsive element, the signals significantly increased after two to three cold stimulations at 4 °C. In the ex vivo study, CREB-targeting genes were significantly upregulated following two or three cold stimulations. The in vivo experiment disclosed that cold stimulation of a mouse limb for 9 days significantly increased mitochondrial DNA copy number and upregulated genes such as Pgc-1α involved in mitochondrial biogenesis. The foregoing results suggest that local cryotherapy increases CREB transcription and upregulates CREB-targeting genes in a manner dependent on cold stimulation frequency and duration. This information may serve as an impetus for further investigations into local cryotherapy as a treatment for sports-related skeletal muscle trauma.

The glycoprotein hormones luteinizing hormone, follicle-stimulating hormone, thyroid-stimulating hormone and chorionic gonadotropin consist of a common alpha-subunit and a hormone-specific beta-subunit. The alpha-subunit is expressed in thyrotrophs, gonadotrophs, and placental cells, and its expression is regulated by extracellular signal molecules. Here, we assessed the regulation of the gene encoding the alpha-subunit in placental JEG-3 cells, using a chromatin-embedded reporter gene under the control of the glycoprotein hormone alpha-subunit promoter. The results show that stimulation of the cells with forskolin, an activator of adenylate cyclase, induced transcription of a reporter gene controlled by the alpha-subunit promoter. Similarly, expression of a nuclear-targeted catalytic subunit of cAMP-dependent protein kinase increased reporter gene transcription. Expression experiments involving constitutively active mutants of MKK6 and MEKK-1 showed that the alpha-subunit promoter is responsive to activation of p38 protein kinase but only slightly responsive to activation of c-Jun N-terminal protein kinase. Finally, we show that stimulation of a Galphaq-coupled designer receptor triggers transcription of a reporter gene controlled by the glycoprotein hormone alpha-subunit promoter, mediated by the transcription factor CREB. Deletion mutagenesis highlights the importance of a tandem cAMP response element within the alpha-subunit promoter that acts as a point of convergence for different signaling pathways.

The rodent collecting duct (CD) expresses a 24p3/NGAL/lipocalin-2 (Lcn2) receptor (Slc22a17) apically to possibly mediate high-affinity reabsorption of filtered proteins by endocytosis, yet its functions remain uncertain. Recently, we showed that hyperosmolarity/-tonicity upregulates Slc22a17 in cultured mouse inner medullary CD cells, whereas activation of toll-like receptor 4 (TLR4) via bacterial lipopolysaccharides (LPS) downregulates Slc22a17. This is similar to the upregulation of Aqp2 by hyperosmolarity/-tonicity and arginine vasopressin (AVP) and downregulation by TLR4 signaling that occur via the transcription factors Nfat5 (TonEBP or OREBP), cAMP-responsive element binding protein (CREB), and nuclear factor-kappa B, respectively. The aim of the study was to determine the effects of osmolarity/tonicity via Nfat5, AVP via CREB and TLR4 signaling on the expression of Slc22a17 and its ligand Lcn2 in the mouse (m) cortical collecting duct cell line mCCD(cl.1). Normosmolarity/-tonicity was 300 mosmol/l whereas addition of 50-100 mmol/l NaCl for up to 72 h induced hyperosmolarity/-tonicity (400-500 mosmol/l). RT-PCR, qPCR, immunoblotting and immunofluorescence microscopy detected Slc22a17 and Lcn2 expression. RNAi silenced Nfat5, and the pharmacological agent 666-15 blocked CREB. Activation of TLR4 occurred with LPS. Similar to Aqp2, hyperosmotic/-tonic media and AVP upregulated Slc22a17 via activation of Nfat5 and CREB, respectively, and LPS/TLR4 signaling downregulated Slc22a17. Conversely, though Nfat5 mediated hyperosmolarity/-tonicity induced downregulation of Lcn2 expression, AVP reduced Lcn2 expression and predominantly apical Lcn2 secretion evoked by LPS, but through a posttranslational mode of action that was independent of cAMP signaling. In conclusion, the hyperosmotic/-tonic upregulation of Slc22a17 in mCCD(cl.1) cells via Nfat5 and by AVP via CREB suggests a contribution of Slc22a17 to adaptive osmotolerance, whereas Lcn2 downregulation could counteract increased proliferation and permanent damage of osmotically stressed cells.

Antiretroviral therapy has effectively suppressed HIV infection and replication and prolonged the lifespan of HIV-infected individuals. In the meantime, various complications including type 2 diabetes associated with long-term antiviral therapy have shown steady increases. Metformin has been the front-line anti-hyperglycemic drug of choice and the most widely prescribed medication for the treatment of type 2 diabetes. However, little is known about the effects of Metformin on HIV infection and replication. In this study, we showed that Metformin treatment enhanced HIV gene expression and transcription in HIV-transfected 293T and HIV-infected Jurkat and human PBMC. Moreover, we demonstrated that Metformin treatment resulted in increased CREB expression and phosphorylation, and TBP expression. Furthermore, we showed that Metformin treatment increased the recruitment of phosphorylated CREB and TBP to the HIV LTR promoter. Lastly, we showed that inhibition of CREB activation significantly abrogated Metformin-enhanced HIV gene expression. Taken together, these results demonstrated that Metformin treatment increased HIV transcription, gene expression, and production though increased CREB phosphorylation and recruitment to the HIV LTR promoter. These findings may help design the clinical management plan and HIV cure strategy of using metformin to treat type 2 diabetes, a comorbidity with an increasing prevalence, in people living with HIV.

Acetylcholine (ACh) is the best one characterized neurotransmitter. Its central roles in the cholinergic areas and central nervous system (CNS) and peripheral (PNS) synapses are well known. It was the first molecule identified as a neurotransmitter and appears to be phylogenetically the oldest one signaling molecules. ACh was detected in bacteria, protozoa, fungi, algae and primitive plants, indicating that the cholinergic system was widely distributed in living organisms before its appearance in the nervous system. The autonomous nervous system (ANS) is an integral part animal kingdom history. It determines fight-escape reactions as well as outlining the vital and cognitive functions bio-organization rhythms. The virus (Covid-19) extraneous effects acting on it could help to better understand its functions. The Blast results show some factors like protein that can be implicated such as bungaro-toxins, phospholipase A2 and the similar prothrombin activator protein. A positive correlation with different toxins is obtained and the Covid-19 double pathogenic mechanism theory is proposed. The process allows us to outline the possibility about toxic-like factors presence.

A reduction of melatonin function contributes to the acceleration of Alzheimer's disease (AD), and understanding molecular processes of melatonin-related signaling is critical for intervention of AD progression. Recently, we synthesized and tested a series of melatonin derivates with donepezil fragments in silico and in vitro. In this study, one of the most potent compounds, 3c, was studied in an in vivo rat model of pinealectomy (pin) and subsequent icvAβ1-42 infusion. Melatonin was used as a referent drug. The treatment with melatonin and 3c (10 mg/kg, i.p. for 14 days) exerted a beneficial effect on memory decline and concomitant rise of Aβ1-42 and pTAU in the hippocampus in the pin + icvAβ1-42 rats. Melatonin supplementation facilitated the non-amyloidogenic signaling via a non-receptor (histone deacetylase sirtuin 1, SIRT1) and receptor-related signaling (MT/ERK/CREB). The hybrid 3c derivate up-regulated the MT1A and MT2B receptors, pERK and pCREB. Our findings strongly support the hypothesis that melatonin-related derivates may become a promising drug candidate in AD therapy.