The effect of SARS-CoV-2 on the development of Parkinson's disease: the role of α-synuclein.

The current coronavirus disease 2019 (COVID-19) can lead to various neurological complications in infected people. These neurological effects include problems in both central nervous system (CNS) and peripheral nervous system (PNS). Hyposmia, a PNS symptom of COVID-19, frequently manifests in the early stages of Parkinson's disease (PD) and serves as an early warning sign of the condition. In addition, the olfactory system is recognized as an early site for the onset of α-synuclein pathology, the pathological hallmark of PD. PD is characterized by accumulation and aggregation of misfolded α-synuclein (α-Syn) into Lewy bodies and Lewy neurites, resulting in the degeneration of dopaminergic neurons in substantia nigra pars compacta (SNpc). Previous research has also shown the involvement of α-Syn in the innate immune response following viral infections. Consequently, the potential link between viral infections and development of PD has gained attention in recent years. However, it's still too early to definitively conclude whether COVID-19 can cause Parkinsonism. Nevertheless, we can explore the likelihood of this connection by examining past studies and possible mechanisms to better understand how COVID-19 might potentially lead to PD following the infection. Based on the various pieces of evidence discussed in this review, we can infer that SARS-CoV-2 promotes the aggregation of α-Syn and, ultimately, leads to PD through at least two mechanisms: the stable binding of the S1 protein to proteins prone to aggregation like α-Syn, and the upregulation of α-Syn as part of the immune response to the infection.

Anti-leishmanial, immunomodulatory and additive potential effect of Piperine on Leishmania major: The in silico and in vitro study of Piperine and its combination.

BACKGROUND: Piperine (Pn), an indole alkaloid compound found in pepper, is an effective compound with anti-leishmanial medications that administered alone or in combination. This study aimed to use Pn for possible biochemical targets and to assess mechanisms of anti-leishmanial action and immunomodulatory roles. METHODS: The ability of Pn to bind to interleukin-12P40 (IL-12P40) and interferon-γ (IFN-γ) was investigated using molecular docking. The leishmanicidal effect of Pn, meglumine antimoniate (Glucantime®; MA), and Pn plus MA was assessed on Leishmania major promastigotes and amastigotes. A real-time PCR was applied to quantify cytokines gene expression in drug-treated murine macrophages. RESULTS: The molecular docking findings indicated that Pn could bind to IL-12P40/IFN-γ. In silico analyses showed an affinity of Pn to IL-12P40/IFN-γ, with the MolDock score of -236.91 and -64.87 kcal/mol, respectively. Pn plus MA reduced the proliferation rate of promastigote and amastigote forms of L. major compared to each drug alone (IC50 = 43.22 and 19.41 µg/mL, respectively). Moreover, the combination drug demonstrated no cytotoxicity as the selectivity index (SI) was 14.81. Also, Th1-related cytokines were upregulated, while Th2-related cytokines were downregulated in Pn combination-treated murine macrophages. CONCLUSIONS: The superior effectiveness of combination therapy on L. major warrants further investigations on the clinical potential of this combination in the treatment of leishmaniasis.

Antiproliferative properties of Turmerone on Leishmania major: Modes of action confirmed by antioxidative and immunomodulatory roles.

Treatment of leishmaniasis by conventional synthetic compounds has faced a serious challenge worldwide. This study was performed to evaluate the effect and modes of action of aromatic Turmerone on the Leishmania major intra-macrophage amastigotes, the causative agent of zoonotic cutaneous leishmaniasis in the Old World. In the findings, the mean numbers of L. major amastigotes in macrophages were significantly decreased in exposure to Turmerone plus meglumine antimoniate (Glucantime®; MA) than MA alone, especially at 50 µg/mL. In addition, Turmerone demonstrated no cytotoxicity as the selectivity index (SI) was 21.1; while it induced significant apoptosis in a dose-dependent manner on L. major promastigotes. In silico molecular docking analyses indicated an affinity of Turmerone to IL-12, with the MolDock score of - 96.8 kcal/mol; which may explain the increased levels of Th1 cytokines and decreased level of IL-10. The main mechanism of action is more likely associated with stimulating a powerful antioxidant and promoting the immunomodulatory roles in the killing of the target organism.

Anti-leishmanial activity of Avicennia marina (Avicenniaceae family) leaves hydroalcoholic extract and its possible cellular mechanisms.

Natural products are the main source of potent antioxidants and anti-leishmanial agents. This study was aimed to evaluate Avicennia marina (Avicenniaceae family) extract inhibitory effect against Leishmania tropica by accessing apoptotic markers and arginase activity. The A. marina were extracted and phytochemical analysis conducted. The inhibitory effect of A. marina was evaluated on L. tropica promastigote and amastigote forms, compared to meglumine antimoniate (Glucantime, MA) as standard drug. The level of apoptosis, Reactive Oxygen Species (ROS) production and arginase activity was assessed in A. marina-treated cells compared to control group. Phytochemical screening of A. marina extract showed strong presence of tannins and saponins. We demonstrated the inhibitory effect of A. marina on promastigote stages in a dose dependent manner. Also, lower 50% inhibitory concentration (IC50) value of amastigotes was indicated in A. marina group compared with the standard group of Glucantime (60.57 ± 1.46 vs. 73.19 ± 10.12 µg/mL, respectively, P < 0.05). Besides, A. marina represented no cytotoxicity as the selectivity index (SI) was 10.7. Also, it showed the potential to induce early apoptosis of 46.5% in promastigotes at 125 µg/mL concentration. Significant reduction of arginase level was observed in both A. marina-treated cells and promastigotes. The promising results indicated higher effectiveness of A. marina in decreasing parasite growth, inducing apoptosis in promastigotes, increasing ROS production and decreasing arginase level. So, A. marina can be a native plant candidate for anti-leishmanial drug in tropical regions with cutaneous leishmaniasis due to L. tropica.

The impact of diabetes on cutaneous leishmaniasis: a case-control field assessment.

This study aimed to assess the associated-risk determinants for cutaneous leishmaniasis (CL) in patients with diabetes mellitus (DM) compared to patients without DM. This case-control study was performed between 2017 and 2019 in southeastern Iran. Overall, 206 participants were selected from patients with DM without CL (11.2%), patients with CL without DM (6.2%), and DM patients concomitance with CL (27.6%) as case groups and healthy individuals as a control group 64 (76%). These cases were compared for parasitological, immunological, biochemical, and hematological parameters. The findings demonstrated that parasitological factors regarding the number, duration, and size of the lesion in CL patients showed a significant difference among patients with and without DM (p < 0.05). Data analysis showed that six major risk factors, including female (odds ratio (OR) = 3.47, confidence interval (CI) = 1.84-6.53, p < 0.001), total protein in CL group (OR = 4.9, CI = 2.3-10.44, p < 0.001), alanine aminotransferase (ALT) concentration in CL group (OR = 0.87, CI = 0.81-0.93, p < 0.001) and DM co-infected with CL group (OR = 0.8, CI = 0.72-0.88, p < 0.001) than healthy group, aspartate aminotransferase (AST) concentration in DM group (OR = 0.86, CI = 0.76-0.98, p = 0.02), transforming growth factor beta)TGF-ß( level in the CL group (OR = 1.03, CI = 1.003-1.05, p = 0.02), and presence of diabetes disease (OR = 2.07, CI = 1.16-3.7, p < 0.05), were significantly linked with the induction of CL lesion. The findings demonstrated a significant relationship between DM and CL in distinct risk determinants. Also, the study revealed that DM enhanced the severity of active CL.

The potential role and apoptotic profile of three medicinal plant extracts on Leishmania tropica by MTT assay, macrophage model and flow cytometry analysis.

INTRODUCTION: Treatment of leishmaniasis with conventional synthetic drugs is a major global challenge. This study was designed to explore the leishmanicidal activity and apoptotic profile of three leaf extracts on Leishmania tropica stages. METHODS: The plants of Quercus velutina, Calotropis procera and Nicotiana tabacum were gathered from Anbarabbad county, in the southeastern part of Kerman province and extracted by maceration method using methanol alcohol. Various concentrations of the extracts (1, 10, 100 and 1000 µg/mL) were used against L. tropica stages to evaluate the inhibitory effect by colorimetric assay, macrophage model and flow cytometry. The MTT assay was conducted to determine the IC50 and CC50 values in promastigotes and J774-A1 macrophages, respectively. For intra-macrophage amastigotes, the leishmanicidal activity was evaluated by calculating the mean number of amastigotes in each macrophage and also IC50 values. The promastigote or amastigote stages with no drug and complete medium without organisms were considered as positive and negative controls, respectively. Meglumine antimoniate (Glucantime) was also used as standard drug. Also, annexin V was used to assess the apoptotic profile. All treatment settings were incubated for a standard time of 72 h in triplicates. Data were analyzed by t-test and ANOVA. RESULTS: The findings showed that all plant extracts inhibited the proliferation rate of promastigotes and amastigotes (P ˂ 0.001); especially, Q. velutina represented the lowest IC50 in both stages. Besides, Q. velutina showed the least number of amastigotes in each macrophage compared to the other groups (4.5 µg/mL). The percentage of parasitic apoptosis at 1000 µg/mL of Q. velutina, C. procera, N. tabacum and Glucantime® were 37.4, 18.6, 8.5 and 52.4, respectively. Amastigotes (clinical stage) were significantly more susceptible to extracts and also Glucantime® than promastigotes (P < 0.001). CONCLUSIONS: This study revealed that all three extracts of Q. velutina, C. procera and N. tabacum exhibited an effective antileishmanial activity and induced apoptosis against the L. tropica promastigotes. Further investigations are essential to isolate and analyze the chemical compositions and their biological properties.

Linguatulosis in small ruminants in southeastern Iran: Epidemiological, histopathological and phylogenetic findings and its public health importance.

Linguatulosis, as a zoonotic disease, can infect most ruminants and cause accidental infections in humans. The objective of this study was to explore the epidemiological, histopathological and phylogenetic profiles of Linguatula serrata infection in sheep and goats and its public health importance during 2015-2018. Mesenteric lymph nodes (MLNs) and liver tissue of goats and sheep were selected randomly in Kerman slaughterhouse. Nymphal samples were used for DNA extraction, amplification and subsequently phylogenetic analysis using 18s rRNA and cytochrome C oxidase subunit 1 (cox1). Overall, of 828 examined livestock, 179 (42.4%) goats and 71 (17.5%) sheep were found to be infected with the nymphal stage of L. serrata. A significant difference was observed between linguatulosis and age. In the histopathological assessment, longitudinal and transverse sections of L. serrata nymphs were observed within the cyst-like spaces surrounded by a wall of fine fibrosis and compact lymphocytes. Moreover, comparing with the L. serrata reference sequences, we found only a single nucleotide change in our goat haplotype in 18s genetic region; while much nucleotide variations were observed in cox1 gene sequences. The results of the present study showed a high infection rate among goats and sheep in southeastern Iran. A better understanding of the disease could be achieved when the parasite species, their molecular characterization and the extent of infection in the area are determined. It is fundamental to select a comprehensive control program in order to take proper preventive and therapeutic measures against the infection.

The potential role of nicotinamide on Leishmania tropica: An assessment of inhibitory effect, cytokines gene expression and arginase profiling.

Leishmaniasis represents a major health concern worldwide which has no effective treatment modality. Nicotinamide (NAm) has been used for a wide range of applications from anticancer to antimicrobial usage. This study aimed to assess the effect of NAm combination on Leishmania tropica Inhibition, as well as on cytokines gene expression and arginase (ARG) activity in L. tropica-infected macrophages in an in vitro model. The leishmanicidal effects of NAm and Glucantime (meglumine antimoniate, MA) alone and in combination (NAm/MA) were evaluated using a colorimetric assay and macrophage model. Additionally, immunomodulatory effects and enzymatic activity were assessed by analyzing Th1 and Th2 cytokines gene expression and ARG level, respectively, in infected macrophages treated with NAm and MA, alone and in combination. Findings indicated that the NAm/MA combination demonstrated greater inhibitory effects on L. tropica promastigotes and amastigotes compared with each drug individually. Docking results proved the affinity of NAm to IFN-γ, which can affirm the increased levels of IFN-γ, IL-12p40 and TNF-α as well as reductions in IL-10 secretion with a dose-response effect, especially in the combination group. The NAm/MA combination also showed a significant reduction in the level of ARG activity at all concentrations used compared to each drug individually. These findings indicate higher effectiveness of NAm plus MA in reducing parasite growth, promoting immune response and inhibiting ARG level. This combination should be considered as a potential therapeutic regimen for treatment of volunteer patients with anthroponotic cutaneous leishmaniasis (ACL) in future control programs.

Host's immune response in unresponsive and responsive patients with anthroponotic cutaneous leishmaniasis treated by meglumine antimoniate: A case-control study of Th1 and Th2 pathways.

The objective of the present study was to compare the host's immune responses between unresponsive and responsive patients with anthroponotic cutaneous leishmaniasis (ACL) treated by meglumine antimoniate. A case-control study was carried out in an endemic focus in Iran. Blood samples were taken from patients and peripheral blood mononuclear cells (PBMCs) were isolated. Two wells were considered for each isolate of unresponsive and responsive patients; one was exposed to L. tropica (Lt-stimulated cells) and the other remained non-exposed (non-stimulated cells). After 24 h of incubation, whole RNA was extracted from each sample. Real-time quantitative PCR was carried out to confirm the differences in expression levels of IL-12 P40, IFN-γ, IL-1ß, IL-4 and IL-10 among isolates. Data were analyzed and P < 0.05 was considered to be statistically significant. In our study, Lt-stimulated cells and non-stimulated cells in unresponsive groups demonstrated significantly lower expression levels of IL-1ß, IL-12 P40 and IFN-γ genes and higher expression levels of IL-4 and IL-10 genes, compared to Lt-stimulated cells and non-stimulated cells in responsive groups. There was a negative correlation between IL-12 P40 with IL-10 and IL-1ß with IL-10 in ACL Lt-stimulated cells in unresponsive group, while a positive correlation between IL-12 P40 with IL-1ß and IL-12 P40 with IFN-γ in ACL Lt-stimulated cells in responsive group. Probably, different immune responses caused by various factors play a major role in the pathogenesis and development of unresponsiveness in ACL patients. The profile and timing of cytokine production correlated well with the treatment outcome of Leishmania infection.

Differential expression of TLRs 2, 4, 9, iNOS and TNF-α and arginase activity in peripheral blood monocytes from glucantime unresponsive and responsive patients with anthroponotic cutaneous leishmaniasis caused by Leishmania tropica.

BACKGROUND: Detection of the mechanism of host/parasite interactions in unresponsive forms of anthroponotic cutaneous leishmaniasis (ACL) caused by Leishmania tropica is helpful for immunotherapy and vaccine development. In the present study, the gene expression of toll-like receptors (TLRs), TNF-α, iNOS and also arginase (ARG) activity in monocytes from Glucantime unresponsive in comparison to responsive patients infected with L. tropica was investigated. METHODS: In this case-control study, patients with unresponsive (n = 10) and responsive (n = 10) ACL were recruited. Gene expression of TLR2, TLR4, TLR9, TNF-α and iNOS was analyzed in L. tropica-exposed monocytes. The level of ARG activity in both isolated promastigotes and the lysates of monocytes was also determined. RESULTS: L. tropica-exposed monocytes represented higher expression of all three TLRs and TNF-α and lower expression of iNOS compared to unexposed ones in both groups of patients. Results revealed a significant down-regulation of TLR2 and TNF-α and up-regulation of TLR9 expression in unresponsive isolates in comparison to responsive ones. Besides, ARG level showed a significant increase in L. tropica-stimulated monocytes and cultured promastigotes from unresponsive isolates versus responsive ones. CONCLUSIONS: The decreased TLR2, TLR4, TNF-α and iNOS and the increased level of TLR9 expression in L. tropica-exposed monocytes from unresponsive isolates and also the increment in ARG activity in their promastigotes and monocytes, might possibly be involved in the severity of the disease and leading to Glucantime unresponsiveness.

A single-group trial of end-stage patients with anthroponotic cutaneous leishmaniasis: Levamisole in combination with Glucantime in field and laboratory models.

Currently, there is no satisfactory treatment modality available for cutaneous leishmaniasis (CL). The major objective of the present study was to explore the effect of immunomodulator-levamisole in combination with Glucantime in end-stage unresponsive patients with anthroponotic CL (ACL). Twenty end-stage unresponsive patients with ACL were identified for participation in this single-group trial study. Simultaneously, each patient was received a combination of levamisole pills along with Glucantime during the remedy course. Several in vitro complementary experiments were performed to evaluate the mode of action of levamisole and Glucantime alone and in combination using a macrophage model, in vitro MTT assay, flow cytometry and quantitative real time PCR (qPCR). Overall, 75% of the patients showed complete clinical cure, 10% partially improved and the remaining (15%) had underlying chronic diseases demonstrated no response to the treatment regimen. In in vitro studies, there was no cytotoxic effect associated with these drugs in the range of our experiments. The findings by the flow cytometric analysis represented that the highest apoptotic values corresponded to the drugs combination (32.23%) at 200 µg/ml concentration. Finally, the gene expression level of IL-12 p40, iNOS and TNF-α promoted while the level of IL-10 and TGF-ß genes reduced as anticipated. The findings clearly indicated that the combination of levamisole and Glucantime should be considered in end-stage unresponsive patients with ACL who have not responded to basic treatments. The immunomodulatory role of levamisole in mounting immune system as documented by the in vitro experiments and further substantiated by this single-group trail study was highlighted.

Unresponsiveness to meglumine antimoniate in anthroponotic cutaneous leishmaniasis field isolates: analysis of resistance biomarkers by gene expression profiling.

BACKGROUND: Resistance to antimonials is a fundamental determinant of treatment failure in anthroponotic cutaneous leishmaniasis (ACL). Detection of reliable molecular markers to distinguish unresponsive and responsive parasites is critical for consolidating strategies to monitor drug efficacy. METHODS: We analysed the expression of five major antimony resistance-associated genes that is aquaglyceroporin1 (AQP1), γ-glutamylcysteine synthetase (γ-GCS), multidrug resistance protein A (MRPA), trypanothione reductase (TR) and thiol-dependent reductase 1 (TDR1), in unresponsive and responsive Leishmania tropica field isolates by quantitative real-time PCR in comparison with sensitive and resistant reference strains. RESULTS: Gene expression analysis showed the down-regulation of AQP1, γ-GCS and TDR1 by a factor of 1.9, 1.7 and 3.55, respectively, in unresponsive isolates vs. responsive ones. The average RNA expression level of MRPA increased by a factor of 1.9 in the unresponsive group. Isolates exhibited a strong positive linear correlation between gene expression of AQP1 and γ-GCS. A negative correlation between the AQP1 and γ-GCS expression level and lesion duration in responsive patients indicated the potential role in diagnosing drug-unresponsive parasites in endemic areas of ACL. CONCLUSION: In cases of inconclusive outcomes of resistance tests in clinical isolates, expression analysis of a set of influential genes can be beneficial to identify distinctive biomarkers between antimony-unresponsive and responsive parasites.

In vitro Protoscolicidal Effects of Cinnamomum zeylanicum Essential Oil and Its Toxicity in Mice.

BACKGROUND: This study investigates the scolicidal effects of Cinnamomum zeylanicum essential oil against the protoscoleces of hydatid cysts and its toxicity in the mice model. MATERIALS AND METHODS: Gas chromatography/mass spectroscopy analyses were used to identify the constituents of essential oil. Protoscoleces were treated with different concentrations of the essential oil (6.25-100 µL/mL) in each test tube for 5-30 min. The viability of protoscoleces was confirmed using eosin exclusion test (0.1% eosin staining). Forty-eight male NMRI mice were also used to determine the toxicity of C. zeylanicum essential oil (0.5-4 mL/kg). RESULTS: The main components were found to be cinnamaldehyde (91.8%), ρ metoxicinamate (1.57%), and α pinene (1.25%). Findings indicate that C. zeylanicum essential oil with the concentrations of 100 and 50 µL/mL killed 100% of protoscoleces after 5 min of exposure. Also, the lower concentrations of C. zeylanicum essential oil motivated a late protoscolicidal effect. The LD50 value of intraperitoneal injection of C. zeylanicum essential oil was 2.07 mL/kg body weight after 48 h, and the maximum nonfatal dose was 1.52 mL/kg body weight. The results also showed that there was no significant toxicity following oral administration of C. zeylanicum essential oil for 2 weeks. CONCLUSION: The results exhibited the favorable scolicidal activity of C. zeylanicum, which could be applied as a natural scolicidal agent in hydatid cyst surgery. SUMMARY: We evaluated the efficacy of Cinnamomum zeylanicum essential oil against hydatid cyst protoscolecesThe viability of protoscoleces was confirmed using eosin exclusion test (0.1% eosin staining)Forty-eight male NMRI mice were also used to determine the toxicity of C. zeylanicum essential oilC. zeylanicum with potent scolicidal activity could be applied as a natural scolicidal agent in surgery. Abbreviations used: GC/MS: Gas chromatography/mass spectrometry analysis; CE: Cystic echinococcosis; LD50: Lethal dose 50%; I.p: Intraperitoneally.