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Acromegaly is a chronic systemic disease caused in the vast majority of cases by growth hormone (GH)-secreting adenoma, with surgery being the first-line treatment. When a cure is not attained with surgery, first-generation somatostatin receptor ligands (fg-SRLs) are the most common medication prescribed. Predictors of response to fg-SRLs have been studied; however, they cannot fully predict the response to fg-SRL. MicroRNAs are small RNAs, the main role of which is messenger RNA (mRNA) post-transcriptional regulation. This study aimed to identify the microRNAs involved in resistance to treatment with fg-SRLs in acromegaly. Ten patients with acromegaly undergoing treatment with fg-SRLs were selected to undergo miRNA sequencing: five controlled and five uncontrolled with treatment. Bioinformatic analysis was performed to detect differentially expressed miRNAs. Then, the same 10 samples were used for validation by qPCR and an additional 22 samples were analyzed, totaling 32 samples. e We found 59 differentially expressed miRNAs in the first analysis. miR-181a-5p and miR-181b-5p were downregulated, and miR-383-5p was upregulated in the uncontrolled group. Receiver operating characteristic (ROC) curve analysis of miR-383-5p showed an NPV of 84.3% and a PPV of 84.5%. In summary, miR-181a-5p, miR-181b-5p, and miR-383-5p are biomarkers of response to fg-SRLs, and they can be used individually or included in prediction models as tools to guide clinical decisions.

Glioblastoma (GBM) is the most common adult primary tumor of the CNS characterized by rapid growth and diffuse invasiveness into the brain parenchyma. The GBM resistance to chemotherapeutic drugs may be due to the presence of cancer stem cells (CSCs). The CSCs activate the same molecular pathways as healthy stem cells such as WNT, Sonic hedgehog (SHH), and Notch. Mutations or deregulations of those pathways play a key role in the proliferation and differentiation of their surrounding environment, leading to tumorigenesis. Here we investigated the effect of SHH signaling pathway inhibition in human GBM cells by using GANT-61, considering stem cell phenotype, cell proliferation, and cell death. Our results demonstrated that GANT-61 induces apoptosis and autophagy in GBM cells, by increasing the expression of LC3 II and cleaved caspase 3 and 9. Moreover, we observed that SHH signaling plays a crucial role in CSC phenotype maintenance, being also involved in the epithelial-mesenchymal transition (EMT) phenotype. We also noted that SHH pathway modulation can regulate cell proliferation as revealed through the analysis of Ki-67 and c-MYC expressions. We concluded that SHH signaling pathway inhibition may be a promising therapeutic approach to treat patients suffering from GBM refractory to traditional treatments.

Dementia, especially Alzheimer's Disease (AD) and vascular dementia, is a major public health problem that continues to expand in both economically emerging and hegemonic countries. In 2017, the World Alzheimer Report estimated that over 50 million people were living with dementia globally. Metabolic dysfunctions of brain structures such as the hippocampus and cerebral cortex have been implicated as risk factors for dementia. Several well-defined metabolic risk factors for AD include visceral obesity, chronic inflammation, peripheral and brain insulin resistance, type 2 diabetes mellitus (T2DM), hypercholesterolemia, and others. In this review, we describe the relationship between the dysmetabolic mechanisms, although still unknown, and dementia, particularly AD. Adiponectin (ADPN), the most abundant circulating adipocytokine, acts as a protagonist in the metabolic dysfunction associated with AD, with unexpected and intriguing dual biological functions. This contradictory role of ADPN has been termed the adiponectin paradox. Some evidence suggests that the adiponectin paradox is important in amyloidogenic evolvability in AD. We present cumulative evidence showing that AD and T2DM share many common features. We also review the mechanistic pathways involving brain insulin resistance. We discuss the importance of the evolvability of amyloidogenic proteins (APs), defined as the capacity of a system for adaptive evolution. Finally, we describe potential therapeutic strategies in AD, based on the adiponectin paradox.

Obesity hypertension is an ongoing pandemic. The first-line medications to treat this condition are still subject to debate. We compared diuretics, calcium-channel blockers (CCB), beta-blockers (BB), angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) as an initial antihypertensive therapy for prevention of cardiovascular morbimortality of hypertensive individuals who are overweight or obese. We conducted a search of the literature for randomized clinical trials in which at least 50% of the participants were overweight or obese. The primary outcomes were all-cause mortality, cardiovascular mortality, acute myocardial infarction (MI), heart failure (HF), stroke, or end-stage renal disease. Our search yielded 16 randomized studies. Comparisons of two classes of drugs with at least two studies indicated that (1) CCB and ACEI increased the risk of HF [relative risk (RR) = 2.26; 95% confidence interval (CI) 1.16–4.40] and stroke [hazard ratio (HR) = 1.13; 1.00–1.26]), respectively, compared to diuretics; and (2) CCB showed a reduction in stroke (HR = 0.77; 0.66–0.89) and total mortality (HR = 0.94; 0.87–1.01) compared to the BB atenolol. Comparisons of two classes of antihypertensive medications with only one study showed that the risk of MI was higher with ARB valsartan versus CCB (HR = 1.19; 95% CI 1.02–1.38, p = 0.02). In contrast, losartan lowered the risk of a composite cardiovascular outcome compared to atenolol (HR = 0.87; 95% CI 0.77–0.98, p = 0.02). In hypertensive subjects with excess weight, diuretics are more effective for preventing HF and stroke than CCB and ACEI, respectively. CCB are a good first-line choice for prevention of cardiovascular disease, except HF.

In 2016, the World Health Organization estimated that more than 1.9 billion adults were overweight or obese. This impressive number shows that weight excess is pandemic. Overweight and obesity are closely associated with a high risk of comorbidities, such as insulin resistance and its most important outcomes, including metabolic syndrome, type 2 diabetes mellitus, and cardiovascular disease. Adiponectin has emerged as a salutary adipocytokine, with insulin-sensitizing, anti-inflammatory, and cardiovascular protective properties. However, under metabolically unfavorable conditions, visceral adipose tissue-derived inflammatory cytokines might reduce the transcription of the adiponectin gene and consequently its circulating levels. Low circulating levels of adiponectin are negatively associated with various conditions, such as insulin resistance, type 2 diabetes mellitus, metabolic syndrome, and cardiovascular disease. In contrast, several recent clinical trials and meta-analyses have reported high circulating adiponectin levels positively associated with cardiovascular mortality and all-cause mortality. These results are biologically intriguing and counterintuitive, and came to be termed “the adiponectin paradox”. Adiponectin paradox is frequently associated with adiponectin resistance, a concept related with the downregulation of adiponectin receptors in insulin-resistant states. We review this contradiction between the apparent role of adiponectin as a health promoter and the recent evidence from Mendelian randomization studies indicating that circulating adiponectin levels are an unexpected predictor of increased morbidity and mortality rates in several clinical conditions. We also critically review the therapeutic perspective of synthetic peptide adiponectin receptors agonist that has been postulated as a promising alternative for the treatment of metabolic syndrome and type 2 diabetes mellitus.

Excessive fat consumption increases the level of fatty acids (FAs) in the blood, which reach the hypothalamus and damage the circuit related to energy balance. In the present study, we used palmitate in a primary culture of purified astrocytes to mimic the fat-rich environment found in obesity. Our results showed increased glial fibrillary acidic protein (GFAP) reactivity in hypothalamic astrocytes compared to cortical astrocytes. In addition, palmitate-treated astrocytes showed no significant changes in cytokine expression and an upregulation of glutathione in the culture medium that may serve as an intrinsic neuroprotective property against excess FA. Additionally, purified hypothalamic neurons were incubated with palmitate-treated astrocyte-conditioned medium (MPAL). MPAL treated-neurons exhibited a reduction in excitatory synapses and enhanced neuritogenesis. Our results suggest that hypothalamic astrocytes react to palmitate differently than cortical astrocytes and influence the behavior of the neural network related to energy balance. Our work brings a better understanding of the interactions among hypothalamic neurons in a high FA environment, similarly to obesity induced by a high-fat diet.

Thyroid hormones (THs) play key roles in brain development and function. The lack of THs during childhood is associated with the impairment of several neuronal connections, cognitive deficits and mental disorders. Several lines of evidence point to astrocytes as TH targets and as mediators of TH action in the central nervous system; however, the mechanisms underlying these events are still not completely known. In this review, we focus on advances in our understanding of the effects of THs on astroglial cells and the impact of these effects on neurone-astrocyte interactions. First, we discuss the signalling pathways involved in TH metabolism and the molecular mechanisms underlying TH receptor function. Then, we discuss data related to the effects of THs on astroglial cells, as well as studies regarding the generation of mutant TH receptor transgenic mice that have contributed to our understanding of TH function in brain development. We argue that astrocytes are key mediators of hormone actions on development of the cerebral cortex and cerebellum and that the identification of the molecules and pathways involved in these events might be important for determining the molecular-level basis of the neural deficits associated with endocrine diseases.

Astrocytes play a critical role in the development and homeostasis of the central nervous system (CNS). Astrocyte dysfunction results in several neurological and degenerative diseases. However, a major challenge to our understanding of astrocyte physiology and pathology is the restriction of studies to animal models, human post-mortem brain tissues, or samples obtained from invasive surgical procedures. Here, we report a protocol to generate human functional astrocytes from cerebral organoids derived from human pluripotent stem cells. The cellular isolation of cerebral organoids yielded cells that were morphologically and functionally like astrocytes. Immunolabelling and proteomic assays revealed that human organoid-derived astrocytes express the main astrocytic molecular markers, including glutamate transporters, specific enzymes and cytoskeletal proteins. We found that organoid-derived astrocytes strongly supported neuronal survival and neurite outgrowth and responded to ATP through transient calcium wave elevations, which are hallmarks of astrocyte physiology. Additionally, these astrocytes presented similar functional pathways to those isolated from adult human cortex by surgical procedures. This is the first study to provide proteomic and functional analyses of astrocytes isolated from human cerebral organoids. The isolation of these astrocytes holds great potential for the investigation of developmental and evolutionary features of the human brain and provides a useful approach to drug screening and neurodegenerative disease modelling.

The microRNAs (miRNAs) as biomarkers with clinical application in oral squamous cell carcinoma (OSCC) has been suggested in literature. These small noncoding RNA molecules can act as oncogenes or tumor suppressor molecules. Altered expression of miR-17, miR-214, and miR-324 was described and related to the sonic hedgehog (SHH) pathway in medulloblastomas. SHH is an important embryonic pathway associated with progression and poor prognosis in OSCC. A better comprehension about the miRNA activity will improve the knowledge about the SHH pathway in oral carcinogenesis. Objective: This study aims to evaluate the Gli1 (an important SHH component) and miR-17, miR-214, and miR-324 expression in OSCC. Study Design: Gli1 evaluation was performed by immunohistochemistry and miR-17, miR-214, and miR-314 expression was investigated using real time polymerase chain reaction in 20 OSCC samples. Results: Gli1 demonstrated a cytoplasmic and nuclear positivity mainly in the undifferentiated histologic grade. Hypoexpression of miR-324 and miR-214 was observed in 40% and 60% of OSCC samples, respectively. A higher expression of miR-17 was identified in 60% of these samples. Conclusion: A possible tumor suppressor and oncogenic profile of miR-324 and miR-17, respectively, as mentioned in medulloblastomas was observed. However, miR-214 did not demonstrate an oncogenic behavior on OSCC.

Oral cancer is the seventh most frequent type of cancer in the Brazilian population, with high invasiveness, metastasis rates, and recurrence. The main risk factors involved are tobacco consumption, alcoholism, and human papillomavirus (HPV) infection. Oral squamous cell carcinoma (OSCC) is the most frequent histologic type. Studies report miR-181 as an important biomarker for the prognosis and survival during glioblastoma multiforme pathogenesis. However, there is no evaluation of their expression in the OSCC, nor their relation with clinical-pathologic data. Objective: The aim of the present study was to evaluate miR-181 family members’ expression in patients with OSCC. Study Design: The expression of miR-181 a/b/c in 20 OSCC and 20 healthy oral mucosa samples was evaluated by quantitative PCR (qPCR). Results: Downregulation of miR-181 a and miR-181 c were observed in 30% and 35% of the samples, respectively. Overexpression of miR-181 b was present in 41% of the cases. A tendency between alcoholism and underexpression of miR-181 c was observed. Conclusions: There is a probable relation between a member of the miR-181 family and an etiologic factor associated with OSCC. However, new studies with a larger number of patients are required to determine the importance of these biomarkers on oral carcinogenesis.

Sphingosine 1-phosphate (S1P) is a bioactive signaling lysophospholipid. Effects of S1P on proliferation, survival, migration, and differentiation have already been described; however, its role as a mediator of interactions between neurons and glial cells has been poorly explored. Here we describe effects of S1P, via the activation of its receptors in astrocytes, on the differentiation of neural progenitor cells (NPC) derived from either embryonic stem cells or the developing cerebral cortex. S1P added directly to NPC induced their differentiation, but S1P-primed astrocytes were able to promote even more pronounced changes in maturation, neurite outgrowth, and arborization in NPC. An increase in laminin by astrocytes was observed after S1P treatment. The effects of S1P-primed astrocytes on neural precursor cells were abrogated by antibodies against laminin. Together, our data indicate that S1P-treated astrocytes are able to induce neuronal differentiation of NPC by increasing the levels of laminin. These results implicate S1P signaling pathways as new targets for understanding neuroglial interactions within the central nervous system.

Lysophosphatidic acid (LPA) plays important roles in many biological processes, such as brain development, oncogenesis and immune functions, via its specific receptors. We previously demonstrated that LPA-primed astrocytes induce neuronal commitment of cerebral cortical progenitors (Spohr et al. 2008). In the present study, we analyzed neurite outgrowth induced by LPA-treated astrocytes and the molecular mechanism underlying this event. LPA-primed astrocytes increase neuronal differentiation, arborization and neurite outgrowth of developing cortical neurons. Treatment of astrocytes with epidermal growth factor (EGF) ligands yielded similar results, suggesting that members of the EGF family might mediate LPA-induced neuritogenesis. Furthermore, treatment of astrocytes with LPA or EGF ligands led to an increase in the levels of the extracellular matrix molecule, laminin (LN), thus enhancing astrocyte permissiveness to neurite outgrowth. This event was reversed by pharmacological inhibitors of the MAPK signaling pathway and of the EGF receptor. Our data reveal an important role of astrocytes and EGF receptor ligands pathway as mediators of bioactive lipids action in brain development, and implicate the LN and MAPK pathway in this process.

The major neural stem cell population in the developing cerebral cortex is composed of the radial glial cells, which generate glial cells and neurons. The mechanisms that modulate the maintenance of the radial glia stem cell phenotype, or its differentiation, are not yet completely understood. We previously demonstrated that the transforming growth factor-β1 (TGF-β1) promotes radial glia differentiation into astrocytes in vitro (Glia 2007; 55:1023-33) through activation of multiple canonical and non-canonical signaling pathways (Dev Neurosci 2012; 34:68-81). However, it remains unknown if TGF-β1 acts in radial glia-astrocyte differentiation in vivo. Here, we addressed the astrogliogenesis induced by TGF-β1 by using the intraventricular in utero injection in vivo approach. We show that injection of TGF-β1 in the lateral ventricles of E14,5 mice embryos resulted in radial glia fibers disorganization and premature gliogenesis, evidenced by appearance of GFAP positive cells in the cortical wall. These events were followed by decreased numbers of neurons in the cortical plate. Together, we also described that TGF-β1 actions are region-dependent, once radial glia cells from dorsal region of the cerebral cortex demonstrated to be more responsive to this cytokine compared with radial glia from lateral cortex either in vitro as well as in vivo. Our work demonstrated that TGF-β1 is a critical cytokine that regulates radial glia fate decision and differentiation into astrocytes in vitro and in vivo. We also suggest that radial glia cells are heterogeneous population that acts as distinct targets of TGF-β1 during cerebral cortex development.

Proper brain neuronal circuitry formation and synapse development is dependent on specific cues, either genetic or epigenetic, provided by the surrounding neural environment. Within these signals, thyroid hormones (T3 and T4) play crucial role in several steps of brain morphogenesis including proliferation of progenitor cells, neuronal differentiation, maturation, migration, and synapse formation. The lack of thyroid hormones during childhood is associated with several impair neuronal connections, cognitive deficits, and mental disorders. Many of the thyroid hormones effects are mediated by astrocytes, although the mechanisms underlying these events are still unknown. In this work, we investigated the effect of 3, 5, 3′-triiodothyronine-treated (T3-treated) astrocytes on cerebral cortex neuronal differentiation. Culture of neural progenitors from embryonic cerebral cortex mice onto T3-treated astrocyte monolayers yielded an increment in neuronal population, followed by enhancement of neuronal maturation, arborization and neurite outgrowth. In addition, real time PCR assays revealed an increase in the levels of the heparan sulfate proteoglycans, Glypican 1 (GPC-1) and Syndecans 3 e 4 (SDC-3 e SDC-4), followed by a decrease in the levels of the chondroitin sulfate proteoglycan, Versican. Disruption of glycosaminoglycan chains by chondroitinase AC or heparanase III completely abolished the effects of T3-treated astrocytes on neuronal morphogenesis. Our work provides evidence that astrocytes are key mediators of T3 actions on cerebral cortex neuronal development and identified potential molecules and pathways involved in neurite extension; which might eventually contribute to a better understanding of axonal regeneration, synapse formation, and neuronal circuitry recover.

Pituitary adenomas comprise approximately 10-15% of intracranial tumors and result in morbidity associated with altered hormonal patterns, therapy and compression of adjacent sella turcica structures. The use of functional foods containing carotenoids contributes to reduce the risk of chronic diseases such as cancer and vascular disorders. In this study, we evaluated the influence of different concentrations of beta-carotene and lycopene on cell viability, colony formation, cell cycle, apoptosis, hormone secretion, intercellular communication and expression of connexin 43, Skp2 and p27(kip1) in ACTH-secreting pituitary adenoma cells, the AtT20 cells, incubated for 48 and 96 h with these carotenoids. We observed a decrease in cell viability caused by the lycopene and beta-carotene treatments; in these conditions, the clonogenic ability of the cells was also significantly decreased. Cell cycle analysis revealed that beta-carotene induced an increase of the cells in S and G2/M phases; furthermore, lycopene increased the proportion of these cells in G0/G1 while decreasing the S and G2/M phases. Also, carotenoids induced apoptosis after 96 h. Lycopene and beta-carotene decreased the secretion of ACTH in AtT20 cells in a dose-dependent manner. Carotenoids blocked the gap junction intercellular communication. In addition, the treatments increased the expression of phosphorylated connexin43. Finally, we also demonstrate decreased expression of S-phase kinase-associated protein 2 (Skp2) and increased expression of p27(kip1) in carotenoid-treated cells. These results show that lycopene and beta-carotene were able to negatively modulate events related to the malignant phenotype of AtT-20 cells, through a mechanism that could involve changes in the expression of connexin 43, Skp2 and p27(kip1); and suggest that these compounds might provide a novel pharmacological approach to the treatment of Cushing's disease.

Lysophosphatidic acid (LPA) plays important roles in many biological processes, such as brain development, oncogenesis and immune functions, via its specific receptors. We previously demonstrated that LPA-primed astrocytes induce neuronal commitment of cerebral cortical progenitors (Spohr et al. 2008). In the present study, we analyzed neurite outgrowth induced by LPA-treated astrocytes and the molecular mechanism underlying this event. LPA-primed astrocytes increase neuronal differentiation, arborization and neurite outgrowth of developing cortical neurons. Treatment of astrocytes with epidermal growth factor (EGF) ligands yielded similar results, suggesting that members of the EGF family might mediate LPA-induced neuritogenesis. Furthermore, treatment of astrocytes with LPA or EGF ligands led to an increase in the levels of the extracellular matrix molecule, laminin (LN), thus enhancing astrocyte permissiveness to neurite outgrowth. This event was reversed by pharmacological inhibitors of the MAPK signaling pathway and of the EGF receptor. Our data reveal an important role of astrocytes and EGF receptor ligands pathway as mediators of bioactive lipids action in brain development, and implicate the LN and MAPK pathway in this process.

Astrocytes play a crucial role in several steps of brain development, such as the proliferation of neural precursors, neuronal migration and differentiation, axonal growth, and synaptogenesis. Astrocyte generation and maturation is dramatically modulated by thyroid hormones (THs). Here, we propose a modified model for studying THs action on astroglial cells, in vitro. We investigated the effect of depletion of THs from fetal bovine serum (FBS) on the expression of the astrocyte maturation markers, GFAP (glial fibrillary acidic protein) and S100beta, and the extracellular matrix (ECM) proteins laminin and fibronectin in cultured astrocytes. To accomplish this, murine cortical astrocytes were cultured in medium supplemented with THs-depleted serum, in contrast to the traditional techniques that use normal FBS which contains considerable amounts of THs. Immunostaining revealed that depletion of THs from FBS did not affect astrocyte proliferation, as observed by the number of astrocytes labeled for the proliferation antigen, Ki67. Surprisingly, western blot and RT-PCR assays revealed decreased levels of GFAP and S100beta in astrocytes cultured with depleted serum. These events were reversed by addition of THs to the medium. Immunostaining and western blot assays did not reveal any difference in the organization and synthesis of the ECM protein, laminin; whereas the levels of fibronectin were decreased by 50% in THs-depleted serum. The fact that decreased expression of GFAP and fibronectin is associated with hypothyroidism in vivo suggests that our work might provide a useful model to assess in vitro the molecular mechanism underlying astrocytic maturation under conditions of THs deficiency.