HTLV-1 infection-induced motor dysfunction, memory impairment, depression, and brain tissues oxidative damage in female BALB/c mice

Aberration of social behavior and gut microbiota induced by cross-fostering implicating the gut-brain axis

The gut microbiota and neurological development of neonatal mice are susceptible to environmental factors that may lead to altered behavior into adulthood. However, the role that changed gut microbiota and neurodevelopment early in life play in this needs to be clarified. In this study, by modeling early-life environmental changes by cross-fostering BALB/c mice, we revealed the effects of the environment during the critical period of postnatal development on adult social behavior and their relationship with the gut microbiota and the nervous system. The neural projections exist between the ascending colon and oxytocin neurons in the paraventricular nuclei (PVN), peripheral oxytocin levels and PVN neuron numbers decreased after cross-fostering, and sex-specific alteration in gut microbiota and its metabolites may be involved in social impairments and immune imbalances brought by cross-fostering via the gut-brain axis. Our findings also suggest that social cognitive impairment may result from a combination of PVN oxytocinergic neurons, gut microbiota, and metabolites.

Folic Acid Ameliorates Anxiety- and Depressive-Like Behavior Induced by Nicotine Withdrawal Through Restoration of Behavioral and Biochemical Alterations in Adolescent Male Rats

BACKGROUND

The present study aimed to assess the efficacy of folic acid (FA) on withdrawal following nicotine (Nic) administration in adolescent male rats.

AIMS AND METHODS

Adolescent male rats were divided into two groups: (1) vehicle and (2) Nic (Nic-2 mg/kg), and were under treatment from 21 to 42 days of age. After that, they continued the experiment without treatment and returned to a regular diet, except for one of those who received Nic. The rats were divided into four groups where they were treated with different doses of FA (5, 10, and 15 mg/kg) and bupropion (Bup) by oral gavage, and the final group included normal rats that received only FA (15 mg/kg) from 42 days of age for three weeks during which withdrawal occurred.

RESULTS

Results showed that adolescent Nic exposure exacerbated the behavioral indices of anxiety- and depression-like behaviors, while FA attenuated the effects of Nic withdrawal on anxiety and depression as well as Bup. In support, the biochemical results demonstrated a balance between oxidant and antioxidant mediators in addition to the increase and decrease of serotonin and monoamine oxidase (MAO) activity in cortical tissue. TNF-α as an inflammatory agent was decreased, whereas IL-10 as an anti-inflammatory parameter was increased.

CONCLUSIONS

The present findings suggest anxiety and depression caused by Nic withdrawal were attenuated by FA more likely through the reduction activity of MAO, the important enzyme responsible for serotonin metabolism along with balance between oxidant/antioxidant and pro-inflammatory/anti-inflammatory mediators. However, various mechanisms might be involved, which requires further investigation.

IMPLICATIONS

Nic withdrawal-induced depression and anxiety like behavior in rats followed by neuro-oxidative damage and neuro-inflammation. FA supplementation as well as Bup improved cognitive disorders induced by Nic withdrawal by increasing neuro-inflammation and neuro-oxidative damage.

Vitamin B12 reversed anxiety and depression induced by adolescent nicotine withdrawal through alteration the inflammatory, oxidative and serotoninergic profiles in male rats

BACKGROUND

The present study aims to assess the effect of vitamin B12 (Vit B12) on depression-like behavior caused by nicotine (Nic) withdrawal, which is more likely due to the anxiogenic effect of Nic in adolescent male rats, through assessing behavioral and biochemical analysis.

METHODS

Adolescent male rats were divided into vehicle (received normal saline), and experimental groups that received Nic (2 mg/kg, intraperitoneally (i.p.)) for three consecutive weeks and after that, the group that received normal saline was divided into two groups, one of which returned to a regular diet, and the second one received Vit B12 (1.5 mg/kg). The Nic group was divided into five groups, one of which received bupropion (Bup, 20 mg/kg), three of which received different doses of Vit B12 (0.5, 1, and 1.5 mg/kg), and the last one returned to a normal diet without treatment, which was considered as the withdrawal period.

RESULTS

Behavioral analysis showed that Nic withdrawal induced anxiety and depression. Vit B12 and Bup reduced anxiety and depression induced by Nic withdrawal. The biochemical analysis demonstrated the more activity of oxidative stress factors and pro-inflammatory cytokines in which Nic was administered, whereas both Vit B12 and Bup reversed the results and improved the activity of both antioxidant and anti-inflammatory parameters. Furthermore, both serum and cortical Vit B12 levels dramatically decreased in nicotine group, whereas treatment with both Vit B12 and Bup as desirable treatments corrected Vit B12 levels.

CONCLUSION

According to the present findings, the results revealed that Vit B12 is comparable with Bup in attenuation of Nic withdrawal symptoms. In addition, both Bup and Vit B12 improved the decreased serum and cortical levels of Vit B12, which caused by nicotine. Administration of Vit B12 in normal animals demonstrated better results in reducing antioxidant and anti-inflammatory parameters, which explores new hope to introduce Vit B12 as a novel antioxidant and anti-inflammatory agent to treat not only withdrawal, but also other diseases related to the prominent role of oxidative stress or inflammatory pathways, such as Alzheimer's disease.

Proteomic Analysis Reveals That Mitochondria Dominate the Hippocampal Hypoxic Response in Mice

Hypoxic stress occurs in various physiological and pathological states, such as aging, disease, or high-altitude exposure, all of which pose a challenge to many organs in the body, necessitating adaptation. However, the exact mechanisms by which hypoxia affects advanced brain function (learning and memory skills in particular) remain unclear. In this study, we investigated the effects of hypoxic stress on hippocampal function. Specifically, we studied the effects of the dysfunction of mitochondrial oxidative phosphorylation using global proteomics. First, we found that hypoxic stress impaired cognitive and motor abilities, whereas it caused no substantial changes in the brain morphology or structure of mice. Second, bioinformatics analysis indicated that hypoxia affected the expression of 516 proteins, of which 71.1% were upregulated and 28.5% were downregulated. We demonstrated that mitochondrial function was altered and manifested as a decrease in NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4 expression, accompanied by increased reactive oxygen species generation, resulting in further neuronal injury. These results may provide some new insights into how hypoxic stress alters hippocampal function via the dysfunction of mitochondrial oxidative phosphorylation.

Selective APC-targeting of a novel Fc-fusion multi-immunodominant recombinant protein (tTax-tEnv:mFcγ2a) for HTLV-1 vaccine development

AIMS

HTLV-1 causes two life-threatening diseases: adult T-cell leukaemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis. Due to the lack of proper treatment, an effective HTLV-1 vaccine is urgently needed.

MAIN METHODS

DNA sequences of 11-19 and 178-186 amino acids of HTLV-1-Tax and SP2 and P21 were fused to the mouse-Fcγ2a, or His-tag called ^tTax-^tEnv:mFcγ2a and ^tTax-^tEnv:His, respectively. These constructs were produced in Pichia pastoris, and their immunogenicity and protective properties were assessed in a mouse challenging model with an HTLV-1-MT2 cell line.

KEY FINDINGS

The immunogenicity assessments showed significant increase in IFN-γ production in animals receiving ^tTax-^tEnv:mFcγ2a (1537.2 ± 292.83 pg/mL) compared to ^tTax-^tEnv:His (120.28 ± 23.9, p = 0.02). IL-12 production also increased in group receiving ^tTax-^tEnv:mFcγ2a than ^tTax-^tEnv:His group, (23 ± 2.6 vs 1.5 ± 0.6, p = 0.01), respectively. The IFN-γ and IL-12 levels in the Fc-immunised group were negatively correlated with PVL (R = -0.82, p < 0.04) and (R = -0.87, p = 0.05), respectively. While, IL-4 was increased by ^tTax-^tEnv:His (21.16 ± 1.76 pg/mL) compared to ^tTax-^tEnv:mFcγ2a (13.7 ± 1.49, p = 0.019) with a negative significant correlation to PVL (R = -0.95, p = 0.001).

SIGNIFICANCE

The mouse challenging assay with ^tTax-^tEnv:mFcγ2a showed 50 % complete protection and a 50 % low level of HTLV-1-PVL compared to the positive control receiving HTLV-1-MT2 (p = 0.001). Challenging experiments for the His-tag protein showed the same outcome (p = 0.002) but by different mechanisms. The Fc-fusion construct induced more robust Th1, and His-tag protein shifted more to Th2 immune responses. Therefore, inducing both T helper responses, but a Th1/Th2 balance in favour of Th1 might be necessary for appropriate protection against HTLV-1 infection, spreading via cell-to-cell contact manner.

The effect of HTLV1 infection on inflammatory and oxidative parameters in the liver, kidney, and pancreases of BALB/c mice

Viral infections are linked to the progression of inflammatory reactions and oxidative stress that play pivotal roles in systemic diseases. To confirm this phenomenon, in the present study, TNF‐α level and oxidative stress markers were examined in the liver, kidney, and pancreas of HTLV1‐infected male BALB/c mice. To this end, twenty BALB/c mice were divided into HTLV1‐infected mice that were inoculated with 1‐million HTLV1‐infected cells (MT‐2), and the control groups. Two months after inoculation, the peripheral blood, mesenteric lymph nodes, liver, kidney, and pancreas were collected after deep anesthetization of mice (ketamine, 30 mg/kg). The extracted DNA of mesenteric lymph nodes was obtained to quantify proviral load (PVL) using quantitative real‐time polymerase chain reaction (qRT‐PCR). The levels of lipid peroxidation, total thiol (SH), nitric oxide (NO), TNF‐α, catalase (CAT), and superoxide dismutase (SOD) activities were examined in the liver, kidney, and pancreases. Furthermore, histopathological changes in the liver and kidney were evaluated. In liver tissue, the levels of MDA, TNF‐α, and blood cell infiltration were significantly increased, and the levels of CAT and SOD were significantly decreased. In the kidney, a reduction in SOD, CAT, and total SH and an increase in MDA and NO were observed. In the pancreas, CAT activity, total SH, and SOD were decreased, and the levels of MDA and NO were enhanced. In terms of TNF‐α production, it has been shown that the level of this inflammatory cytokine was increased in the liver, kidney, and pancreas. The HTLV1 may have a role in inducing inflammatory reactions and oxidative stress pathways in the tissues.

Identification of joint gene players implicated in the pathogenesis of HTLV-1 and BLV through a comprehensive system biology analysis

BACKGROUND

Human T-cell lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) are oncogenic viruses that induce adult T cell leukemia/lymphoma (ATLL) and enzootic bovine leukosis (EBL), respectively. HTLV-1 principally infects CD4⁺ T cells comprising regulatory T cells (Tregs), T helper 1 (Th1), and T helper 2 (Th2), while BLV infects B lymphocytes. Both viruses may impel cell proliferation and malignancy.

METHODS

To survey the transcriptomic variations due to HTLV-1 and BLV infection and further hematologic malignancies, differential expression genes (DEGs) were explored between leukemia and normal samples using the DESeq2 package. Gene set enrichment analyses (GSEA) were then performed to identify significant gene sets using the FGSEA package. Afterward, the protein-protein interaction (PPI) networks were reconstructed using the STRING online database. Eventually, the hub significant genes and modules were determined through network analysis and MCODE algorithm, respectively.

RESULTS

Our results uncloaked that four common functional gene sets including mitotic-spindle, G2M-checkpoint, E2F-targets, and MYC-targets-V1 are involved in the human and ovine hosts. Furthermore, twelve up-regulated hub genes including BIRC5, CCNA2, CCNB2, BUB1, DLGAP5, TOP2A, PBK, ASPM, UBE2C, CEP55, KIF20A, and NUSAP1 were identified which were similarly activated in both human and ovine hosts. They mostly participate in pathways including cell cycle, cell division, DNA damage responses, growth factors production, and p53 signaling pathway. The dysregulated hub genes and pathways seem to be involved in the development and progression of the infected cells toward malignancy.

CONCLUSION

There is common gene groups between HTLV-1 and BLV infections that promote viral malignancy through enhancing cell proliferation and overall survival of cancer cells. The dysregulated genes and pathways may be the efficient candidates for the therapy of the mentioned life-threatening diseases.

Human T-Cell Leukemia Virus Type 1 Changes Leukocyte Number and Oxidative Stress in the Lung and Blood of Female BALB/c Mice

BACKGROUND

Human T-cell leukemia virus type 1(HTLV-1) infection is likely to induce nonneoplastic inflammatory pulmonary diseases. Therefore, an experimental study was conducted to evaluate the leukocytes' number alteration and oxidative stress in the lung and blood of HTLV-1-infected BALB/c mice, which could be of benefit for the recognition of HTLV-1 mechanism in the induction of pulmonary disorders.

MATERIALS AND METHODS

Twenty female BALB/c mice were divided into two groups of control and HTLV-1-infected animals. The HTLV-1-infected group was inoculated with 106 MT-2 HTLV-1-infected cells. Two months later, the infection was confirmed using real-time polymerase chain reaction, and then lung pathological changes, total and differential inflammatory cell counts in the blood and bronchoalveolar lavage fluid (BALF), along with oxidative stress biomarker levels in the BALF and lung tissue were evaluated.

RESULTS

In the HTLV-1-infected group, the peribronchitis score (P < 0.01), the number of total leukocytes, neutrophils, lymphocytes, and monocytes (P < 0.05) in the blood and BALF were increased. The number of eosinophils in the blood of the HTLV-1-infected group was higher than in the control group (P < 0.01), whereas the number of basophils of BALF was increased in the HTLV-1-infected group (P < 0.001). The lung and BALF oxidative stress results showed that the MDA level was increased, while the total thiol level and superoxide dismutase activity were decreased in the HTLV-1-infected group (P < 0.01).

CONCLUSION

The HTLV-1 infection seems to induce pulmonary inflammatory reactions by recruiting leukocytes as well as inducing oxidative stress in the lung tissue.

The brain consequences of systemic inflammation were not fully alleviated by ibuprofen treatment in mice

BACKGROUND

Extensive data point to the immune system as an important factor underlying the pathogenesis of brain diseases. Epidemiological studies have shown that long-term treatment with non-steroidal anti-inflammatory drugs (NSAIDs) significantly reduces the onset and progression of Alzheimer's disease. The present study aimed to investigate whether ibuprofen (IBU) is able to prevent the long-lasting alterations of brain function induced by systemic inflammation.

METHODS

Mice received intraperitoneal injections of lipopolysaccharide (LPS; 250 µg/kg/day) for seven consecutive days. Ibuprofen administration (40 mg/kg/day) was started three days before the LPS injections and continued until the last day of LPS injection. Within the next 2 weeks, mice performances on the behavioral tests were evaluated, and then brain tissue samples for biochemical analyses were collected.

RESULTS

The findings showed that ibuprofen significantly improved mice's performance in the passive avoidance test and reduced anxiety- and depressive-like behaviors. However, ibuprofen could not significantly improve spatial memory in the Morris water maze test and recognition ability in the novel object recognition test. TNF-α and IL-1β cytokines levels and malondialdehyde (MDA) concentration in the hippocampal tissues of LPS-treated mice were significantly lowered by ibuprofen treatment, whereas no significant effects on IL-10 production and hippocampal BDNF levels were observed. In addition, ibuprofen did not significantly reduce amyloid-β_1-40 levels in the hippocampus of LPS-treated animals.

CONCLUSION

Overall, the findings of the present study suggest that some, but not all, of the adverse effects of systemic inflammation are alleviated by ibuprofen treatment.