Plant Monoterpenes and Essential Oils as Potential Anti-Ageing Agents: Insights from Preclinical Data

Ageing is a natural process characterized by a time-dependent decline of physiological integrity that compromises functionality and inevitably leads to death. This decline is also quite relevant in major human pathologies, being a primary risk factor in neurodegenerative diseases, metabolic disorders, cardiovascular diseases and musculoskeletal disorders. Bearing this in mind, it is not surprising that research aiming at improving human health during this process has burst in the last decades. Importantly, major hallmarks of the ageing process and phenotype have been identified, this knowledge being quite relevant for future studies towards the identification of putative pharmaceutical targets, enabling the development of preventive/therapeutic strategies to improve health and longevity. In this context, aromatic plants have emerged as a source of potential bioactive volatile molecules, mainly monoterpenes, with many studies referring to their anti-ageing potential. Nevertheless, an integrated review on the current knowledge is lacking, with several research approaches studying isolated ageing hallmarks or referring to an overall anti-ageing effect, without depicting possible mechanisms of action. Herein, we aim to provide an updated systematization of the bioactive potential of volatile monoterpenes on recently proposed ageing hallmarks, and highlight the main mechanisms of action already identified, as well as possible chemical entity-activity relations. By gathering and categorizing the available scattered information, we also aim to identify important research gaps that could help pave the way for future research in the field.

Unveiling the role of osteosarcoma-derived secretome in premetastatic lung remodelling

BACKGROUND

Lung metastasis is the most adverse clinical factor and remains the leading cause of osteosarcoma-related death. Deciphering the mechanisms driving metastatic spread is crucial for finding open therapeutic windows for successful organ-specific interventions that may halt or prevent lung metastasis.

METHODS

We employed a mouse premetastatic lung-based multi-omics integrative approach combined with clinical features to uncover the specific changes that precede lung metastasis formation and identify novel molecular targets and biomarker of clinical utility that enable the design of novel therapeutic strategies.

RESULTS

We found that osteosarcoma-bearing mice or those preconditioned with the osteosarcoma cell secretome harbour profound lung structural alterations with airway damage, inflammation, neutrophil infiltration, and extracellular matrix remodelling with increased deposition of fibronectin and collagens by resident stromal activated fibroblasts, favouring the adhesion of disseminated tumour cells. Systemic-induced microenvironmental changes, supported by transcriptomic and histological data, promoted and accelerated lung metastasis formation. Comparative proteome profiling of the cell secretome and mouse plasma identified a large number of proteins involved in extracellular-matrix organization, cell-matrix adhesion, neutrophil degranulation, and cytokine-mediated signalling, consistent with the observed lung microenvironmental changes. Moreover, we identified EFEMP1, an extracellular matrix glycoprotein exclusively secreted by metastatic cells, in the plasma of mice bearing a primary tumour and in biopsy specimens from osteosarcoma patients with poorer overall survival. Depletion of EFEMP1 from the secretome prevents the formation of lung metastasis.

CONCLUSIONS

Integration of our data uncovers neutrophil infiltration and the functional contribution of stromal-activated fibroblasts in ECM remodelling for tumour cell attachment as early pro-metastatic events, which may hold therapeutic potential in preventing or slowing the metastatic spread. Moreover, we identified EFEMP1, a secreted glycoprotein, as a metastatic driver and a potential candidate prognostic biomarker for lung metastasis in osteosarcoma patients. Osteosarcoma-derived secreted factors systemically reprogrammed the lung microenvironment and fostered a growth-permissive niche for incoming disseminated cells to survive and outgrow into overt metastasis. Daily administration of osteosarcoma cell secretome mimics the systemic release of tumour-secreted factors of a growing tumour in mice during PMN formation; Transcriptomic and histological analysis of premetastatic lungs revealed inflammatory-induced stromal fibroblast activation, neutrophil infiltration, and ECM remodelling as early onset pro-metastatic events; Proteome profiling identified EFEMP1, an extracellular secreted glycoprotein, as a potential predictive biomarker for lung metastasis and poor prognosis in osteosarcoma patients. Osteosarcoma patients with EFEMP1 expressing biopsies have a poorer overall survival.

Cx43 can form functional channels at the nuclear envelope and modulate gene expression in cardiac cells

Classically associated with gap junction-mediated intercellular communication, connexin43 (Cx43) is increasingly recognized to possess non-canonical biological functions, including gene expression regulation. However, the mechanisms governing the localization and role played by Cx43 in the nucleus, namely in transcription modulation, remain unknown. Using comprehensive and complementary approaches encompassing biochemical assays, super-resolution and immunogold transmission electron microscopy, we demonstrate that Cx43 localizes to the nuclear envelope of different cell types and in cardiac tissue. We show that translocation of Cx43 to the nucleus relies on Importin-β, and that Cx43 significantly impacts the cellular transcriptome, likely by interacting with transcriptional regulators. In vitro patch-clamp recordings from HEK293 and adult primary cardiomyocytes demonstrate that Cx43 forms active channels at the nuclear envelope, providing evidence that Cx43 can participate in nucleocytoplasmic shuttling of small molecules. The accumulation of nuclear Cx43 during myogenic differentiation of cardiomyoblasts is suggested to modulate expression of genes implicated in this process. Altogether, our study provides new evidence for further defining the biological roles of nuclear Cx43, namely in cardiac pathophysiology.

Antibiofilm Effect of Lavandula multifida Essential Oil: A New Approach for Chronic Infections

Fungal infections are associated with high morbidity and mortality rates, being highly prevalent in patients with underlying health complications such as chronic lung disease, HIV, cancer, and diabetes mellitus. To mitigate these infections, the development of effective antifungals is imperative, with plants standing out as promising sources of bioactive compounds. In the present study, we focus on the antibiofilm potential of Lavandula multifida essential oil (EO) against dermatophyte strains and Candida albicans. The EO was characterized using GC and GC-MS, and its antifungal effect was assessed on both biofilm formation and disruption. Biofilm mass, extracellular matrix, and viability were quantified using crystal violet, safranin, and XTT assays, respectively, and morphological alterations were confirmed using optical and scanning electron microscopy. L. multifida EO showed very high amounts of carvacrol and was very effective in inhibiting and disrupting fungal biofilms. The EO significantly decreased biofilm mass and viability in all tested fungi. In addition, a reduction in dermatophytes' extracellular matrix was observed, particularly during biofilm formation. Morphological alterations were evident in mature biofilms, with a clear decrease in hypha diameter. These promising results support the use of L. multifida EO in the development of effective plant-based antifungal products.

Aromatic Plant-Based Functional Foods: A Natural Approach to Manage Cardiovascular Diseases

Aromatic plants and their essential oils have shown beneficial effects on the cardiovascular system and, therefore, are potential raw materials in the development of functional foods. However, despite their undeniable potential, essential oils present several limitations that need to be addressed, such as stability, poor solubility, undesirable sensory effects, and low bioavailability. The present review provides a current state-of-the-art on the effects of volatile extracts obtained from aromatic plants on the cardiovascular system and focuses on major challenges that need to be addressed to increase their use in food products. Moreover, strategies underway to overcome these limitations are pointed out, thus anticipating a great appreciation of these extracts in the functional food industry.

Mediterranean Lavenders from Section Stoechas: An Undervalued Source of Secondary Metabolites with Pharmacological Potential

Globally, climate change and wildfires are disrupting natural ecosystems, thus setting several endemic species at risk. The genus Lavandula is widely present in the Mediterranean region and its species, namely, those included in the section Stoechas, are valuable resources of active compounds with several biological assets. Since ancient times lavenders have been used in traditional medicine and for domestic purposes. These species are melliferous, decorative, and essential oil-producing plants with a high economic interest in the pharmaceutical, flavor, fragrance, and food industries. The essential oils of Lavandula section Stoechas are characterized by high amounts of 1,8-cineole, camphor, fenchone, and specifically for L. stoechas subsp. luisieri one of the major compounds is trans-α-necrodyl acetate. On the other hand, the diversity of non-volatile components like phenolic compounds, such as phenolic acids and flavonoids, make these species an important source of phytochemicals with pharmacological interest. Rosmarinic, caffeic, and salvianolic B acids are the major phenolic acids, and luteolin and eriodictyol-O-glucuronide are the main reported flavonoids. However, the concentration of these secondary metabolites is strongly affected by the plant’s phenological phase and varies in Lavandula sp. from different areas of origin. Indeed, lavender extracts have shown promising antioxidant, antimicrobial, anti-inflammatory, and anticancer properties as well as several other beneficial actions with potential for commercial applications. Despite several studies on the bioactive potential of lavenders from the section Stoechas, a systematized and updated review of their chemical profile is lacking. Therefore, we carried out the present review that gathers relevant information on the different types of secondary metabolites found in these species as well as their bioactive potential.

Testing Explant Sources, Culture Media, and Light Conditions for the Improvement of Organogenesis in Pinus ponderosa (P. Lawson and C. Lawson)

Pinus. ponderosa (P. Lawson and C. Lawson) is a commercial tree and one of the most important forest species in North America. Ponderosa pine suffers hardship when going through vegetative propagation and, in some cases, 15-30 years are needed to achieve full reproductive capacity. Based on previous works on P. ponderosa regeneration through in vitro organogenesis and trying to improve the published protocols, our objective was to analyze the influence of different types of explants, basal culture media, cytokinins, auxins, and light treatments on the success of shoot multiplication and rooting phases. Whole zygotic embryos and 44 µΜ 6-benzyladenine showed the best results in terms of explants survival. For shoot organogenesis, whole zygotic embryos and half LP (LP medium, Quoirin and Lepoivre, 1977, modified by Aitken-Christie et al., 1988) macronutrients were selected. A significant positive interaction between whole zygotic embryos and half LP macronutrients was found for the percentage of explants forming shoots. Regarding the light treatments applied, a significantly higher percentage of shoots elongated enough to be rooted was detected in shoots growing under blue LED at a light intensity of 61.09 µmol m^-2 s^-1. However, the acclimatization percentage was higher in shoots previously cultivated under fluorescent light at a light intensity of 61.71 µmol m^-2 s^-1. Anatomical studies using light microscopy and scanning electron microscopy showed the light treatments promoted differences in anatomical aspects in in vitro shoots; needles of plantlets exposed to red and blue LEDs revealed less stomata compared with needles from plantlets exposed to fluorescent light.

Essential Oils from Côa Valley Lamiaceae Species: Cytotoxicity and Antiproliferative Effect on Glioblastoma Cells

Lavandula pedunculata (Mill.) Cav., Mentha cervina L. and Thymus mastichina (L.) L. subsp. mastichina are representative species of the Côa Valley's flora, a Portuguese UNESCO World Heritage Site. L. pedunculata and T. mastichina are traditionally used to preserve olives and to aromatize bonfires on Saint John's Eve, while M. cervina is mainly used as a spice for river fish dishes. Despite their traditional uses, these aromatic plants are still undervalued, and literature regarding their bioactivity, especially anticancer, is scarce. In this work, the morphology of secretory structures was assessed by scanning electron microscopy (SEM), and the composition of essential oils (EOs) was characterized by gas chromatography-mass spectrometry (GC-MS). The study proceeded with cytotoxic evaluation of EOs in tumor and non-tumor cells with the cell death mechanism explored in glioblastoma (GB) cells. L. pedunculata EO presented the most pronounced cytotoxic/antiproliferative activity against tumor cells, with moderate cytotoxicity against non-tumor cells. Whereas, M. cervina EO exhibited a slightly lower cytotoxic effect against tumor cells and did not affect the viability of non-tumor cells. Meanwhile, T. mastichina EO did not induce a strong cytotoxic effect against GB cells. L. pedunculata and M. cervina EOs lead to cell death by inducing apoptosis in a dose-dependent manner. The present study suggests that L. pedunculata and M. cervina EOs have a strong cytotoxic and antiproliferative potential to be further studied as efficient antitumor agents.

Natural Products in Cardiovascular Diseases: The Potential of Plants from the Allioideae Subfamily (Ex-Alliaceae Family) and Their Sulphur-Containing Compounds

Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide and, together with associated risk factors such as diabetes, hypertension, and dyslipidaemia, greatly impact patients' quality of life and health care systems. This burden can be alleviated by fomenting lifestyle modifications and/or resorting to pharmacological approaches. However, due to several side effects, current therapies show low patient compliance, thus compromising their efficacy and enforcing the need to develop more amenable preventive/therapeutic strategies. In this scenario, medicinal and aromatic plants are a potential source of new effective agents. Specifically, plants from the Allioideae subfamily (formerly Alliaceae family), particularly those from the genus Allium and Tulbaghia, have been extensively used in traditional medicine for the management of several CVDs and associated risk factors, mainly due to the presence of sulphur-containing compounds. Bearing in mind this potential, the present review aims to gather information on traditional uses ascribed to these genera and provide an updated compilation of in vitro and in vivo studies validating these claims as well as clinical trials carried out in the context of CVDs. Furthermore, the effect of isolated sulphur-containing compounds is presented, and whenever possible, the relation between composition and activity and the mechanisms underlying the beneficial effects are pointed out.

Essential Oils in Respiratory Mycosis: A Review

Respiratory mycosis is a major health concern, due to the expanding population of immunosuppressed and immunocompromised patients and the increasing resistance to conventional antifungals and their undesired side-effects, thus justifying the development of new therapeutic strategies. Plant metabolites, namely essential oils, represent promising preventive/therapeutic strategies due to their widely reported antifungal potential. However, regarding fungal infections of the respiratory tract, information is disperse and no updated compilation on current knowledge is available. Therefore, the present review aims to gather and systematize relevant information on the antifungal effects of several essential oils and volatile compounds against the main type of respiratory mycosis that impact health care systems. Particular attention is paid to Aspergillus fumigatus, the main pathogen involved in aspergillosis, Candida auris, currently emerging as a major pathogen in certain parts of the world, and Cryptococcus neoformans, one of the main pathogens involved in pulmonary cryptococcosis. Furthermore, the main mechanisms of action underlying essential oils’ antifungal effects and current limitations in clinical translation are presented. Overall, essential oils rich in phenolic compounds seem to be very effective but clinical translation requires more comprehensive in vivo studies and human trials to assess the efficacy and tolerability of these compounds in respiratory mycosis.

ER-mitochondria communication is involved in NLRP3 inflammasome activation under stress conditions in the innate immune system

Endoplasmic reticulum (ER) stress and mitochondrial dysfunction, which are key events in the initiation and/or progression of several diseases, are correlated with alterations at ER-mitochondria contact sites, the so-called "Mitochondria-Associated Membranes" (MAMs). These intracellular structures are also implicated in NLRP3 inflammasome activation which is an important driver of sterile inflammation, however, the underlying molecular basis remains unclear. This work aimed to investigate the role of ER-mitochondria communication during ER stress-induced NLRP3 inflammasome activation in both peripheral and central innate immune systems, by using THP-1 human monocytes and BV2 microglia cells, respectively, as in vitro models. Markers of ER stress, mitochondrial dynamics and mass, as well as NLRP3 inflammasome activation were evaluated by Western Blot, IL-1β secretion was measured by ELISA, and ER-mitochondria contacts were quantified by transmission electron microscopy. Mitochondrial Ca2+ uptake and polarization were analyzed with fluorescent probes, and measurement of aconitase and SOD2 activities monitored mitochondrial ROS accumulation. ER stress was demonstrated to activate the NLRP3 inflammasome in both peripheral and central immune cells. Studies in monocytes indicate that ER stress-induced NLRP3 inflammasome activation occurs by a Ca2+-dependent and ROS-independent mechanism, which is coupled with upregulation of MAMs-resident chaperones, closer ER-mitochondria contacts, as well as mitochondrial depolarization and impaired dynamics. Moreover, enhanced ER stress-induced NLRP3 inflammasome activation in the immune system was found associated with pathological conditions since it was observed in monocytes derived from bipolar disorder (BD) patients, supporting a pro-inflammatory status in BD. In conclusion, by demonstrating that ER-mitochondria communication plays a key role in the response of the innate immune cells to ER stress, this work contributes to elucidate the molecular mechanisms underlying NLRP3 inflammasome activation under stress conditions, and to disclose novel potential therapeutic targets for diseases associated with sterile inflammation.

LAMP2A regulates the loading of proteins into exosomes

Exosomes are extracellular vesicles of endosomal origin that are released by practically all cell types across metazoans. Exosomes are active vehicles of intercellular communication and can transfer lipids, RNAs, and proteins between different cells, tissues, or organs. Here, we describe a mechanism whereby proteins containing a KFERQ motif pentapeptide are loaded into a subpopulation of exosomes in a process that is dependent on the membrane protein LAMP2A. Moreover, we demonstrate that this mechanism is independent of the ESCRT machinery but dependent on HSC70, CD63, Alix, Syntenin-1, Rab31, and ceramides. We show that the master regulator of hypoxia HIF1A is loaded into exosomes by this mechanism to transport hypoxia signaling to normoxic cells. In addition, by tagging fluorescent proteins with KFERQ-like sequences, we were able to follow the interorgan transfer of exosomes. Our findings open new avenues for exosome engineering by allowing the loading of bioactive proteins by tagging them with KFERQ-like motifs.

1,8-cineole Ameliorates Right Ventricle Dysfunction Associated With Pulmonary Arterial Hypertension by Restoring Connexin 43 and Mitochondrial Homeostasis

For the first time, the present study unravels a cardiospecific therapeutic approach for Pulmonary Arterial Hypertension (PAH), a disease with a very poor prognosis and high mortality rates due to right ventricle dysfunction. We first established a new in vitro model of high-pressure-induced hypertrophy that closely resembles heart defects associated with PAH and validated our in vitro findings on a preclinical in vivo model of monocrotaline (MCT)-induced PAH. Our results showed the in vitro antihypertrophic effect of 1,8-cineole, a monoterpene widely found in several essential oils. Also, a decrease in RV hypertrophy and fibrosis, and an improvement in heart function in vivo was observed, when 1,8-cineole was applied topically. Furthermore, 1,8-cineole restored gap junction protein connexin43 distribution at the intercalated discs and mitochondrial functionality, suggesting it may act by preserving cardiac cell-to-cell communication and bioenergetics. Overall, our results point out a promising therapeutic compound that can be easily applied topically, thus paving the way for the development of effective cardiac-specific therapies to greatly improve PAH outcomes.

The Role of Essential Oils and Their Main Compounds in the Management of Cardiovascular Disease Risk Factors

Cardiovascular diseases (CVDs) are a global health burden that greatly impact patient quality of life and account for a huge number of deaths worldwide. Despite current therapies, several side effects have been reported that compromise patient adherence; thus, affecting therapeutic benefits. In this context, plant metabolites, namely volatile extracts and compounds, have emerged as promising therapeutic agents. Indeed, these compounds, in addition to having beneficial bioactivities, are generally more amenable and present less side effects, allowing better patient tolerance. The present review is an updated compilation of the studies carried out in the last 20 years on the beneficial potential of essential oils, and their compounds, against major risk factors of CVDs. Overall, these metabolites show beneficial potential through a direct effect on these risk factors, namely hypertension, dyslipidemia and diabetes, or by acting on related targets, or exerting general cellular protection. In general, monoterpenic compounds are the most studied regarding hypotensive and anti-dyslipidemic/antidiabetic properties, whereas phenylpropanoids are very effective at avoiding platelet aggregation. Despite the number of studies performed, clinical trials are sparse and several aspects related to essential oil’s features, namely volatility and chemical variability, need to be considered in order to guarantee their efficacy in a clinical setting.

Antifungal and Anti-Inflammatory Potential of Bupleurum rigidum subsp. paniculatum (Brot.) H.Wolff Essential Oil

Fungal infections remain a major health concern with aromatic plants and their metabolites standing out as promising antifungal agents. The present study aims to assess, for the first time, the antifungal and anti-inflammatory potential of Bupleurum subsp. paniculatum (Brot.) H.Wolff essential oil from Portugal. The oil obtained by hydrodistillation and characterized by GC-MS, showed high amounts of monoterpene hydrocarbons, namely α-pinene (29.0–36.0%), β–pinene (26.1–30.7%) and limonene (10.5–13.5%). The antifungal potential was assessed, according to CLSI guidelines, against several clinical and collection strains. The essential oil showed a broad fungicidal effect being more potent against Cryptococcus neoformans and dermatophytes. Moreover, a significant germ tube inhibition was observed in Candida albicans as well as a disruption of mature biofilms, thus pointing out an effect of the oil against relevant virulent factors. Furthermore, fungal ultrastructural modifications were detected through transmission electron microscopy, highlighting the nefarious effect of the oil. Of relevance, the oil also evidenced anti-inflammatory activity through nitric oxide inhibition in macrophages activated with lipopolysaccharide. In addition, the essential oil’s bioactive concentrations did not present toxicity towards macrophages. Overall, the present study confirmed the bioactive potential of B. rigidum subsp. paniculatum essential oil, thus paving the way for the development of effective drugs presenting concomitantly antifungal and anti-inflammatory properties.

Airborne environmental fine particles induce intense inflammatory response regardless of the absence of heavy metal elements

Airborne environmental particles (EP) more commonly referred as particulate matter (PM) are an illustrative marker of air pollution that is associated with adverse effects on human health. Considering, PM is a complex mixture, not only in terms of its chemical composition, but also in the range of particle size, it is difficult to identify which attribute contributes more for the toxicity. Currently, there is no report about the immunotoxicological effects caused by PM with reduced content of heavy metals. This study intends to address this gap and provides a detailed characterization and immunotoxicity evaluation of PM collected in an urban area with heavy traffic congestion. Environmental particles were separated by different sizes though a sucrose gradient. This method allowed to achieve 4 sized fractions: EP f 15 % with a mean diameter of 284 nm ± 1.86 nm, EP f 25 % with a mean diameter of 461 nm ± 1.72 nm, EP f 35 % with a mean diameter of 1845 nm ± 251 nm and EP f 45 % with a mean diameter of 2204 nm ± 310 nm. Only the fractions with the smallest sizes (EP f 15 % and EP f 25 %) were subsequently studied. The chemical composition of both fractions was not substantially different, and the dominant elements were C, O, Ca and K. Only EP f 25 % showed to have a small amount of Fe. Therefore, the heavy metal elements were eliminated through centrifugation. Essentially, we found that the EP f 15 % was more cytotoxic in RAW 264.7 cells than EP f 25 %, which indicates the smaller size as the motive for the higher toxicity. In addition, both fractions of EP presented a good internalization in macrophages after 2 h exposure and induced the production of reactive oxygen species in a concentration-dependent manner. Moreover, EP f 15 % and EP f 25 % led to a strong secretion of proinflammatory cytokines (TNF-α and IL-6) in human peripheral blood mononuclear cells (hPBMCs) in the 3 concentrations tested. The inflammatory response observed was independent of the presence of heavy metals and endotoxins, since these last were suppressed by using polymyxin B sulfate. This report emphasizes the importance of an adequate physicochemical characterization and adequate controls in the experiments to achieve a right interpretation of the biological effects caused by PM.

Protective Effects of Phenylpropanoids and Phenylpropanoid-rich Essential Oils on the Cardiovascular System

BACKGROUND

Cardiovascular diseases are the leading cause of global mortality with a tendency to increase due to population ageing as well as an increase in associated risk factors. Although current therapies improve survival rates, they are associated with several side effects, thus justifying the development of novel preventive and/or therapeutic approaches. In this way, plant metabolites such as essential oils have emerged as promising agents due to their biological effects.

OBJECTIVE

Bearing in mind that several essential oils are characterized by high amounts of phenylpropanoids, which may play a crucial role in the activity of these volatile extracts, a comprehensive and systematic review focusing on the cardiovascular effects of phenylpropanoid-rich essential oils is presented.

METHODS

Popular search engines including PubMed, Science Direct, Scopus and Google Scholar were consulted and papers from 2000 onwards were selected. Non-volatile phenylpropanoids were not considered in this review.

RESULTS

A compilation of the current knowledge on this thematic pointed out beneficial effects for volatile phenylpropanoids namely hypotensive, vasorelaxant, antiplatelet aggregation, antidyslipidaemic and antidiabetic, as well as protective properties against ischemia/reperfusion injury and heart hypertrophy.

CONCLUSION

A better understanding of the protective effects of phenylpropanoids on the cardiovascular system is presented, thus paving the way towards future research on plant-based therapies for cardiovascular diseases.

Unveiling the bioactive potential of the essential oil of a Portuguese endemism, Santolina impressa

ETHNOPHARMACOLOGICAL RELEVANCE

Santolina species are widely used in traditional medicine in the Mediterranean region for their anti-inflammatory, antimicrobial, antispasmodic, digestive, and analgesic properties. S. impressa, a Portuguese endemism, is traditionally recognized for its beneficial anti-inflammatory properties in several gastrointestinal affections and is also used in oropharyngeal infections.

AIM OF THE STUDY

The present study aims to characterize the essential oil of S. impressa growing in Portugal and validate its traditional uses by assessing the anti-inflammatory potential of its essential oil at concentrations without toxicity. The antifungal properties of the oil are also addressed, as well as, the putative mechanism of action underlying these effects.

MATERIAL AND METHODS

The essential oil was obtained in accordance with the European Pharmacopoeia and characterized by GC and GC-MS. The anti-inflammatory potential of the oil was assessed on LPS-stimulated macrophages, through the production of nitric oxide (NO) using the Griess reaction. Putative mechanisms of action included the role of the oil as a NO scavenger, as well as its effect on the expression of two key pro-inflammatory enzymes, iNOS and COX-2 by Western blot analysis. The antifungal effect of the oil was evaluated according to the CLSI guidelines on several yeast and filamentous strains and on two major virulence factors in Candida albicans, namely germ tubes and biofilms. Ultrastructural modifications on dermatophytes were also unveiled by transmission electron microscopy.

RESULTS

S. impressa essential oil was primarily characterized by the presence of monoterpene hydrocarbons and oxygenated monoterpenes, being the main compounds β-pinene (22.5%), 1,8-cineole (10.0%), limonene (9.1%), camphor (8.1%) and β-phellandrene (8.0%). A significant decrease (ca 60.0%) in nitrite levels was observed in LPS-stimulated macrophages treated with the oil without affecting cell viability. This effect could be explained by a great reduction on iNOS expression (85.0% inhibition), thus underpinning the anti-inflammatory potential of the oil. The oil also showed a fungicidal effect, being more active against Cryptococcus neoformans, Epidermophyton floccosum and Trichophytum rubrum. For these dermatophytes, significant ultrastructural modifications in cell wall structure were detected. Strikingly, for C. albicans, the oil showed a significant anti-infective potential (at 0.07 mg/mL for germ tube inhibition and 0.02 mg/mL for biofilm disruption) before fungal growth inhibition occurred.

CONCLUSIONS

Our results validate the main traditional use ascribed to S. impressa, namely its anti-inflammatory effect. In addition, an antifungal potential is pointed out, thus corroborating the antimicrobial uses and adding new value to an endemic species poorly recognized by the industry.

Exosomes and STUB1/CHIP cooperate to maintain intracellular proteostasis

Deregulation of proteostasis is a main feature of many age-related diseases, often leading to the accumulation of toxic oligomers and insoluble protein aggregates that accumulate intracellularly or in the extracellular space. To understand the mechanisms whereby toxic or otherwise unwanted proteins are secreted to the extracellular space, we inactivated the quality-control and proteostasis regulator ubiquitin ligase STUB1/CHIP. Data indicated that STUB1 deficiency leads both to the intracellular accumulation of protein aggregates and to an increase in the secretion of small extracellular vesicles (sEVs), including exosomes. Secreted sEVs are enriched in ubiquitinated and/or undegraded proteins and protein oligomers. Data also indicates that oxidative stress induces an increase in the release of sEVs in cells depleted from STUB1. Overall, the results presented here suggest that cells use exosomes to dispose of damaged and/or undegraded proteins as a means to reduce intracellular accumulation of proteotoxic material.

MicroRNA-424(322) as a new marker of disease progression in pulmonary arterial hypertension and its role in right ventricular hypertrophy by targeting SMURF1

Aims

MicroRNAs (miRNAs) have been implicated in the pathogenesis of pulmonary hypertension (PH), a multifactorial and progressive condition associated with an increased afterload of the right ventricle leading to heart failure and death. The main aim of this study was to correlate the levels of miR-424(322) with the severity and prognosis of PH and with right ventricle hypertrophy progression. Additionally, we intended to evaluate the mechanisms and signalling pathways whereby miR-424(322) secreted by pulmonary arterial endothelial cells (PAECs) impacts cardiomyocytes.

Methods and results

Using quantitative real-time PCR, we showed that the levels of circulating miR-424(322) are higher in PH patients when compared with healthy subjects. Moreover, we found that miR-424(322) levels correlated with more severe symptoms and haemodynamics. In the subgroup of Eisenmenger syndrome patients, miR-424(322) displayed independent prognostic value. Furthermore, we demonstrated that miR-424(322) targets SMURF1, through which it sustains bone morphogenetic protein receptor 2 signalling. Moreover, we showed that hypoxia induces the secretion of miR-424(322) by PAECs, which after being taken up by cardiomyocytes leads to down-regulation of SMURF1. In the monocrotaline rat model of PH, we found an association between circulating miR-424(322) levels and the stage of right ventricle hypertrophy, as well as an inverse correlation between miR-424(322) and SMURF1 levels in the hypertrophied right ventricle.

Conclusions

This study shows that miR-424(322) has diagnostic and prognostic value in PH patients, correlating with markers of disease severity. Additionally, miR-424(322) can target proteins with a direct effect on heart function, suggesting that this miRNA can act as a messenger linking pulmonary vascular disease and right ventricle hypertrophy.

Unveiling the Antifungal Potential of Two Iberian Thyme Essential Oils: Effect on C. albicans Germ Tube and Preformed Biofilms

Fungal infections remain a burden worldwide, thus underpinning the need for effective new therapeutic approaches. In the present study, the antifungal effect of the essential oils of two thyme species, Thymus camphoratus and Thymus carnosus, used in traditional medicine in Portugal, as well as their major compounds was assessed. A special focus was placed on their effect on Candida albicans virulence factors. Also, the safety profile of the essential oils was assessed on keratinocytes. The essential oils were analyzed by gas chromatography (GC) and gas chromatography/mass spectroscopy (GC/MS). The minimal inhibitory and minimal fungicidal concentrations of the essential oils and their main compounds were assessed on reference and clinical strains. Also, their effect on C. albicans germ tube formation, metabolism, and biofilm disruption were considered. T. camphoratus oil was rich in 1,8-cineole and α-pinene whereas T. carnosus oil showed high amounts of borneol and camphene. Regarding the antifungal effect, both oils were more active against Cryptococcus neoformans and dermatophytes and very effective in inhibiting C. albicans germ tube formation, at doses well below their MIC and in a higher extend than the isolated compounds and fluconazole, an antifungal drug widely used in the clinic. The oils also disrupted preformed C. albicans biofilms. Furthermore, no toxicity was observed at pharmacological relevant concentrations towards keratinocytes. Our study validates the traditional uses ascribed to these Iberian species. Furthermore, it brings new insights on the antifungal potential and mechanism of action of these thyme species, thus paving the way for the development of novel effective antifungal drugs.

New insights on the anti-inflammatory potential and safety profile of Thymus carnosus and Thymus camphoratus essential oils and their main compounds

ETHNOPHARMACOLOGICAL RELEVANCE

Thymus camphoratus and T. carnosus are widely used in Portugal for the treatment of inflammatory-related conditions, such as inflammation of the respiratory tract, being the later also used as an antitussive.

AIM OF THE STUDY

Bearing in mind the lack of scientific studies focused on the pharmacological activity of Thymus camphoratus and T. carnosus, this work was designed to validate the anti-inflammatory properties ascribed to these traditional species and concomitantly to unveil both the putative molecular mechanisms behind their bioactivity as well as the safety profile of their essential oils and major compounds.

MATERIALS AND METHODS

The chemical composition of the essential oils was assessed by gas chromatography (GC) and gas chromatography - mass spectroscopy (GC/MS). The nitric oxide (NO) scavenging potential of the oils was tested using S-nitroso-N-acetyl-D,L-penicillamine (SNAP) as NO donor. The anti-inflammatory potential of the essential oils and their major compounds was evaluated by measuring the nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated macrophages as well as the expression of the pro-inflammatory enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Importantly, and in an attempt to assess the safety profile of the oils and respective major compounds, their effect on macrophages and hepatocytes viability was also determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

RESULTS

T. carnosus essential oil was characterized by high amounts of borneol and camphene whereas T. camphoratus oil was rich in 1,8-cineole and borneol. The later presented higher pharmacological activity showing inhibitory effects towards NO production at lower concentrations (0.16 µL/mL) and concomitantly inhibiting the expression of two crucial pro-inflammatory proteins, iNOS and COX-2 (at 0.32 µL/mL). Since no NO scavenging activity was achieved, it is reasonable to conclude that the anti-inflammatory activity of the essential oils occurs upstream of iNOS expression, probably through inhibition of relevant pro-inflammatory signal transduction pathways. Importantly, at bioactive concentrations, the essential oils were devoid of toxicity towards macrophages and hepatocytes. The activity of the isolated compounds was far from that observed for the essential oils, thus suggesting that the anti-inflammatory activity is due to a synergic effect between several compounds in the mixture.

CONCLUSION

Overall, the results herein presented sustain and strengthen the anti-inflammatory properties traditionally ascribed to T. carnosus and T. camphoratus. Additionally, the molecular mechanisms associated to their pharmacological activity were highlighted, opening new avenues for the development of effective anti-inflammatory herbal medicinal products.

Disclosing the functional changes of two genetic alterations in a patient with Chronic Progressive External Ophthalmoplegia: Report of the novel mtDNA m.7486G>A variant

Chronic Progressive External Ophthalmoplegia (CPEO) is characterized by ptosis and ophthalmoplegia and is usually caused by mitochondrial DNA (mtDNA) deletions or mt-tRNA mutations. The aim of the present work was to clarify the genetic defect in a patient presenting with CPEO and elucidate the underlying pathogenic mechanism. This 62-year-old female first developed ptosis of the right eye at the age of 12 and subsequently the left eye at 45 years, and was found to have external ophthalmoplegia at the age of 55 years. Histopathological abnormalities were detected in the patient's muscle, including ragged-red fibres, a mosaic pattern of COX-deficient muscle fibres and combined deficiency of respiratory chain complexes I and IV. Genetic investigation revealed the "common deletion" in the patient's muscle and fibroblasts. Moreover, a novel, heteroplasmic mt-tRNASer(UCN) variant (m.7486G>A) in the anticodon loop was detected in muscle homogenate (50%), fibroblasts (11%) and blood (4%). Single-fibre analysis showed segregation with COX-deficient fibres for both genetic alterations. Assembly defects of mtDNA-encoded complexes were demonstrated in fibroblasts. Functional analyses showed significant bioenergetic dysfunction, reduction in respiration rate and ATP production and mitochondrial depolarization. Multilamellar bodies were detected by electron microscopy, suggesting disturbance in autophagy. In conclusion, we report a CPEO patient with two possible genetic origins, both segregating with biochemical and histochemical defect. The "common mtDNA deletion" is the most likely cause, yet the potential pathogenic effect of a novel mt-tRNASer(UCN) variant cannot be fully excluded.

Mitochondria-Targeted Photodynamic Therapy with a Galactodendritic Chlorin to Enhance Cell Death in Resistant Bladder Cancer Cells

Here, we report the rational design of a new third-generation photosensitizer (PS), a chlorin conjugated with galactodendritic units, ChlGal₈, to improve the effectiveness of bladder cancer treatment. ChlGal₈ shows better photochemical and photophysical properties than a recently reported homologous porphyrin, PorGal₈. In addition to inheriting excellent photostability, the ability to generate singlet oxygen, and the ability to interact with the proteins galectin-1 and human serum albumin (HSA), ChlGal₈ exhibits high absorption in the red region of the electromagnetic spectrum. In vitro studies of anticancer activity of ChlGal₈ revealed that once this PS is taken up by UM-UC-3 bladder cancer cells, it induces high cytotoxicity after a single dose of light irradiation. In HT-1376 bladder cancer cells resistant to therapy, a second light irradiation treatment enhanced in vitro and in vivo photodynamic efficacy. The enhanced phototoxicity in HT-1376 cancer cells seems to be due to the ability of ChlGal₈ to accumulate in the mitochondria, via facilitative glucose transporter 1 (GLUT1), in the period between single and repeated irradiation. A photodynamic therapy (PDT) regimen using an extra dose of light irradiation and ChlGal₈ as PS represents a promising strategy in treating resistant cancers in a clinical setting.

Targeting of adenovirus to endothelial cells by a bispecific single-chain diabody directed against the adenovirus fiber knob domain and human endoglin (CD105)

The use of adenoviruses for antivascular cancer gene therapy is limited by their low transduction efficiency for endothelial cells. We have developed a recombinant bispecific antibody as a molecular bridge, linking the adenovirus capsid to the endothelial cell surface protein endoglin, for vascular targeting of adenoviruses. Endoglin (CD105), a component of the transforming growth factor beta receptor complex, represents a promising target for antivascular cancer therapy. Endoglin is expressed predominantly on endothelial cells and is upregulated in angiogenic areas of tumors. We isolated single-chain Fv fragments directed against human endoglin from a human semisynthetic antibody library. One of the isolated scFv fragments (scFv C4) bound specifically to various proliferating primary endothelial cells or cell lines including HUVEC, HDMEC, HMVEC, and HMEC. ScFv C4 was therefore used to construct a bispecific single-chain diabody directed against endoglin and the adenovirus fiber knob domain (scDb EDG-Ad). This bispecific molecule mediated enhanced and selective adenovirus transduction of HUVECs, which was independent from binding to the coxsackievirus and adenovirus receptor (CAR) and alpha(v)-integrins. Thus, adenovirus infection was redirected to a new cellular receptor (CD105) and cell entry pathway. These results demonstrate the utility of bispecific single-chain diabodies, which can be produced in large quantities in bacteria, for the retargeting of adenoviruses in cancer gene therapy.

Dendritic cells derived from peripheral monocytes express endothelial markers and in the presence of angiogenic growth factors differentiate into endothelial-like cells

CD14-positive monocytes obtained from human peripheral blood were cultured with GM-CSF and IL-4. During the early culture phase immature dendritic cells (DCs) developed which not only expressed CD1a, HLA-DR and CD86, but also expressed the endothelial cell markers von Willebrand factor (vWF), VE-cadherin and VEGF receptors Flt-1 and Flt-4. Further maturation of DCs was achieved by prolonged cultivation with TNFalpha. These cells showed typical DC morphology and like professional antigen-presenting cells (APCs) expressed CD83 and high levels of HLA-DR and CD86. However, if immature DCs were grown with VEGF, bFGF and IGF-1 on fibronectin/vitronectin-coated culture dishes, a marked change in morphology into caudated or oval cells occurred. In the presence of these angiogenic growth factors the cultured cells developed into endothelial-like cells (ELCs), characterized by increased expression of vWF, KDR and Flt-4 and a disappearance of CD1a and CD83. Addition of IL-4 and Oncostatin M also increased VE-cadherin expression, and the loosely adherent cells formed clusters, cobblestones and network-like structures. vWF- expressing ELCs mainly originated from CD1a-positive cells, and VEGF was responsible for the decrease in the expression of the DC markers CD1a and CD83. In mixed leukocyte cultures, mature DCs were more potent APCs than ELCs. Moreover, Ac-LDL uptake, and the formation of tubular structures on a plasma matrix was restricted to ELCs. These results suggest that in the presence of specific cytokines immature DCs have the potential to differentiate along different lineages, i.e. into a cell type resembling ELCs.