Stress and reactivation of latent herpes simplex virus: a fusion of behavioral medicine and molecular biology

A holistic perspective on herpes simplex virus (HSV) ecology and evolution

Herpes simplex viruses (HSV) cause chronic infection in humans that are characterized by periodic episodes of mucosal shedding and ulcerative disease. HSV causes millions of infections world-wide, with lifelong bouts of viral reactivation from latency in neuronal ganglia. Infected individuals experience different levels of disease severity and frequency of reactivation. There are two distantly related HSV species, with HSV-1 infections historically found most often in the oral niche and HSV-2 infections in the genital niche. Over the last two decades, HSV-1 has emerged as the leading cause of first-episode genital herpes in multiple countries. While HSV-1 has the highest level of genetic diversity among human alpha-herpesviruses, it is not yet known how quickly the HSV-1 viral population in a human host adapts over time, or if there are population bottlenecks associated with viral reactivation and/or transmission. It is also unknown how the ecological environments in which HSV infections occur influence their evolutionary trajectory, or that of co-occurring viruses and microbes. In this review, we explore how HSV accrues genetic diversity within each new infection, and yet maintains its ability to successfully infect most of the human population. A holistic examination of the ecological context of natural human infections can expand our awareness of how HSV adapts as it moves within and between human hosts, and reveal the complexity of these lifelong human-virus interactions. These insights may in turn suggest new areas of exploration for other chronic pathogens that successfully evolve and persist among their hosts.

A systematic review of the impact of psychosocial factors on immunity: Implications for enhancing BCG response against tuberculosis

BACKGROUND

Tuberculosis (TB) remains an urgent global public health priority, causing 1.5 million deaths worldwide in 2018. There is evidence that psychosocial factors modulate immune function; however, how this may influence TB risk or BCG vaccine response, and whether this pathway can be modified through social protection, has not been investigated. This paper aims to: a) systematically review evidence of how psychosocial factors influence the expression of biomarkers of immunity, and b) apply this general evidence to propose plausible TB-specific pathways for future study.

METHODS

Papers reporting on the impact of psychosocial stressors on immune biomarkers in relation to infectious disease risk were identified through a search of the databases MEDLINE, PsycINFO, Global Health and PsycEXTRA alongside reference list and citation searching of key papers. Data extraction and critical appraisal were carried out using a standardised form. The findings were tabulated and synthesised narratively by infectious disease category, and used to propose plausible mechanisms for how psychosocial exposures might influence immune outcomes relevant to TB and BCG response.

RESULTS

27,026 citations were identified, of which 51 met the inclusion criteria. The literature provides evidence of a relationship between psychosocial factors and immune biomarkers. While the direction and strength of associations is heterogenous, some overarching patterns emerged: adverse psychosocial factors (e.g. stress) were generally associated with compromised vaccine response and higher antibody titres to herpesviruses, and vice versa for positive psychosocial factors (e.g. social support).

CONCLUSIONS

The evidence identifies pathways linking psychosocial factors and immune response: co-viral infection and immune suppression, both of which are potentially relevant to TB and BCG response. However, the heterogeneity in the strength and nature of the impact of psychosocial factors on immune function, and lack of research on the implications of this relationship for TB, underscore the need for TB-specific research.

What Is the Molecular Signature of Mind-Body Interventions? A Systematic Review of Gene Expression Changes Induced by Meditation and Related Practices

There is considerable evidence for the effectiveness of mind–body interventions (MBIs) in improving mental and physical health, but the molecular mechanisms of these benefits remain poorly understood. One hypothesis is that MBIs reverse expression of genes involved in inflammatory reactions that are induced by stress. This systematic review was conducted to examine changes in gene expression that occur after MBIs and to explore how these molecular changes are related to health. We searched PubMed throughout September 2016 to look for studies that have used gene expression analysis in MBIs (i.e., mindfulness, yoga, Tai Chi, Qigong, relaxation response, and breath regulation). Due to the limited quantity of studies, we included both clinical and non-clinical samples with any type of research design. Eighteen relevant studies were retrieved and analyzed. Overall, the studies indicate that these practices are associated with a downregulation of nuclear factor kappa B pathway; this is the opposite of the effects of chronic stress on gene expression and suggests that MBI practices may lead to a reduced risk of inflammation-related diseases. However, it is unclear how the effects of MBIs compare to other healthy interventions such as exercise or nutrition due to the small number of available studies. More research is required to be able to understand the effects of MBIs at the molecular level.

Stress Hormones Epinephrine and Corticosterone Selectively Modulate Herpes Simplex Virus 1 (HSV-1) and HSV-2 Productive Infections in Adult Sympathetic, but Not Sensory, Neurons

Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2) infect and establish latency in peripheral neurons, from which they can reactivate to cause recurrent disease throughout the life of the host. Stress is associated with the exacerbation of clinical symptoms and the induction of recurrences in humans and animal models. The viruses preferentially replicate and establish latency in different subtypes of sensory neurons, as well as in neurons of the autonomic nervous system that are highly responsive to stress hormones. To determine if stress-related hormones modulate productive HSV-1 and HSV-2 infections within sensory and autonomic neurons, we analyzed viral DNA and the production of viral progeny after treatment of primary adult murine neuronal cultures with the stress hormones epinephrine and corticosterone. Both sensory trigeminal ganglion (TG) and sympathetic superior cervical ganglion (SCG) neurons expressed adrenergic receptors (activated by epinephrine) and the glucocorticoid receptor (activated by corticosterone). Productive HSV infection colocalized with these receptors in SCG but not in TG neurons. In productively infected neuronal cultures, epinephrine treatment significantly increased the levels of HSV-1 DNA replication and production of viral progeny in SCG neurons, but no significant differences were found in TG neurons. In contrast, corticosterone significantly decreased the levels of HSV-2 DNA replication and production of viral progeny in SCG neurons but not in TG neurons. Thus, the stress-related hormones epinephrine and corticosterone selectively modulate acute HSV-1 and HSV-2 infections in autonomic, but not sensory, neurons.IMPORTANCE Stress exacerbates acute disease symptoms resulting from HSV-1 and HSV-2 infections and is associated with the appearance of recurrent skin lesions in millions of people. Although stress hormones are thought to impact HSV-1 and HSV-2 through immune system suppression, sensory and autonomic neurons that become infected by HSV-1 and HSV-2 express stress hormone receptors and are responsive to hormone fluctuations. Our results show that autonomic neurons are more responsive to epinephrine and corticosterone than are sensory neurons, demonstrating that the autonomic nervous system plays a substantial role in HSV pathogenesis. Furthermore, these results suggest that stress responses have the potential to differentially impact HSV-1 and HSV-2 so as to produce divergent outcomes of infection.

Social regulation of human gene expression: mechanisms and implications for public health

Recent analyses have discovered broad alterations in the expression of human genes across different social environments. The emerging field of social genomics has begun to identify the types of genes sensitive to social regulation, the biological signaling pathways mediating these effects, and the genetic polymorphisms that modify their individual impact. The human genome appears to have evolved specific "social programs" to adapt molecular physiology to the changing patterns of threat and opportunity ancestrally associated with changing social conditions. In the context of the immune system, this programming now fosters many of the diseases that dominate public health. The embedding of individual genomes within a broader metagenomic network provides a framework for integrating molecular, physiologic, and social perspectives on human health.

Nervous system regulation of the cancer genome

Genomics-based analyses have provided deep insight into the basic biology of cancer and are now clarifying the molecular pathways by which psychological and social factors can regulate tumor cell gene expression and genome evolution. This review summarizes basic and clinical research on neural and endocrine regulation of the cancer genome and its interactions with the surrounding tumor microenvironment, including the specific types of genes subject to neural and endocrine regulation, the signal transduction pathways that mediate such effects, and therapeutic approaches that might be deployed to mitigate their impact. Beta-adrenergic signaling from the sympathetic nervous system has been found to up-regulated a diverse array of genes that contribute to tumor progression and metastasis, whereas glucocorticoid-regulated genes can inhibit DNA repair and promote cancer cell survival and resistance to chemotherapy. Relationships between socio-environmental risk factors, neural and endocrine signaling to the tumor microenvironment, and transcriptional responses by cancer cells and surrounding stromal cells are providing new mechanistic insights into the social epidemiology of cancer, new therapeutic approaches for protecting the health of cancer patients, and new molecular biomarkers for assessing the impact of behavioral and pharmacologic interventions.

Effects of thyroid hormone on HSV-1 gene regulation: implications in the control of viral latency and reactivation

Thyroid hormone (TH) is involved in many biological functions such as animal development, cell differentiation, etc. Variation and/or disruption of plasma TH level often led to abnormalities and physiological disorders. TH exerts the effects through its nuclear receptors (TR). Literature showed that procedures resulted in TH alteration also linked to reactivation of several viruses including Herpes Simplex Virus Type -1 (HSV-1). Bioinformatic analyses revealed a number of putative TH responsive elements (TRE) located in the critical regulatory regions of HSV-1 genes such as thymidine kinase (TK), latency associated transcript (LAT), etc. Studies using neuronal cell lines have provided evidences demonstrating that liganded TR regulated viral gene expression via chromatin modification and controlled viral replication. The removal of TH reversed the inhibition and induced the viral replication previously blocked by TH. These results suggest that TH may have implication to participate in the control of reactivation during HSV-1 latency.

Does psychosocial stress predict symptomatic herpes simplex virus recurrence? A meta-analytic investigation on prospective studies

Previous psychological studies have paid extensive attention to the association between psychosocial stress and symptomatic herpes simplex virus (HSV) recurrence, but subsequent research has been conducted and conflicting findings have been published. We aimed to quantify the longitudinal association between psychosocial stress and recurrent HSV in the contemporary literature. We searched Medline; PsycINFO; Web of Science; PubMed up to March 2009, and included prospective studies that investigated associations between psychosocial stress and symptomatic HSV recurrence. Two reviewers independently extracted data on study characteristics, quality, and estimates of associations. The overall meta-analysis examining 11 articles (17 psychosocial and disease related relationships) exhibited a robust positive association between psychosocial stress and symptomatic HSV recurrence (correlation coefficient as combined effect size 0.083, 95% confidence interval 0.025-0.141, p=0.005). This finding was supported by more conservative analysis of aggregate effects and by sensitivity analysis of the methodologically strong studies. There were indications of publication bias in some analyses. Intriguingly, sensitivity analyses demonstrated that psychological distress was more strongly associated with symptomatic HSV recurrence than stress stimuli per se, and that psychosocial stress tended to be more strongly associated with oral than genital herpes recurrence. In conclusion, the current review reveals a robust relationship between psychosocial stress and symptomatic HSV recurrence, justifying further research in this field, especially clinical trials evaluating the efficacy of stress reduction interventions on HSV recurrence.

beta-Adrenoreceptors reactivate Kaposi's sarcoma-associated herpesvirus lytic replication via PKA-dependent control of viral RTA

Reactivation of Kaposi's sarcoma-associated herpesvirus (KSHV) lytic replication is mediated by the viral RTA transcription factor, but little is known about the physiological processes controlling its expression or activity. Links between autonomic nervous system activity and AIDS-associated Kaposi's sarcoma led us to examine the potential influence of catecholamine neurotransmitters. Physiological concentrations of epinephrine and norepinephrine efficiently reactivated lytic replication of KSHV in latently infected primary effusion lymphoma cells via beta-adrenergic activation of the cellular cyclic AMP/protein kinase A (PKA) signaling pathway. Effects were blocked by PKA antagonists and mimicked by pharmacological and physiological PKA activators (prostaglandin E2 and histamine) or overexpression of the PKA catalytic subunit. PKA up-regulated RTA gene expression, enhanced activity of the RTA promoter, and posttranslationally enhanced RTA's trans-activating capacity for its own promoter and heterologous lytic promoters (e.g., the viral PAN gene). Mutation of predicted phosphorylation targets at RTA serines 525 and 526 inhibited PKA-mediated enhancement of RTA trans-activating capacity. Given the high catecholamine levels at sites of KSHV latency such as the vasculature and lymphoid organs, these data suggest that beta-adrenergic control of RTA might constitute a significant physiological regulator of KSHV lytic replication. These findings also suggest novel therapeutic strategies for controlling the activity of this oncogenic gammaherpesvirus in vivo.

Psychological stress and the human immune system: a meta-analytic study of 30 years of inquiry

The present report meta-analyzes more than 300 empirical articles describing a relationship between psychological stress and parameters of the immune system in human participants. Acute stressors (lasting minutes) were associated with potentially adaptive upregulation of some parameters of natural immunity and downregulation of some functions of specific immunity. Brief naturalistic stressors (such as exams) tended to suppress cellular immunity while preserving humoral immunity. Chronic stressors were associated with suppression of both cellular and humoral measures. Effects of event sequences varied according to the kind of event (trauma vs. loss). Subjective reports of stress generally did not associate with immune change. In some cases, physical vulnerability as a function of age or disease also increased vulnerability to immune change during stressors.

Psychological stress and the human immune system: a meta-analytic study of 30 years of inquiry

The present report meta-analyzes more than 300 empirical articles describing a relationship between psychological stress and parameters of the immune system in human participants. Acute stressors (lasting minutes) were associated with potentially adaptive upregulation of some parameters of natural immunity and downregulation of some functions of specific immunity. Brief naturalistic stressors (such as exams) tended to suppress cellular immunity while preserving humoral immunity. Chronic stressors were associated with suppression of both cellular and humoral measures. Effects of event sequences varied according to the kind of event (trauma vs. loss). Subjective reports of stress generally did not associate with immune change. In some cases, physical vulnerability as a function of age or disease also increased vulnerability to immune change during stressors.

Sleep quality and responses to insufficient sleep in women on different work shifts

1. The aim of this study was to examine degrees of cognitive behavioural effects of fatigue, mood changes and somatic responses to sleep loss in women with and without sufficient sleep, and to explore possible links between effects of sleep loss and specific sleep disturbances in selected groups. 2. A total 156 women working in a casualty department on different work shifts responded to a questionnaire which measured sleep quality, strain and symptoms related to working conditions, as well as effects of sleep loss. 3. About 40% of the women had perceived insufficient sleep during the last 6 months. They perceived significantly worse sleep quality and a higher degree of strain according to working conditions than the others. Palpitation and dysphoria as effects of sleep loss were independently predicted by sleep quality. Dysphoria was also predicted by difficulty in falling asleep. Cognitive behavioural effects of fatigue was predicted by disturbed sleep. Palpitation effects led to a 10-fold increase in the probability of cognitive behavioural effects of fatigue. The effects were most prominent among women suffering from gastrointestinal problems of long duration and chronic pain. 4. Responses to reduced sleep quality in women constitute a form of stress, with sympathetic activation, increased susceptibility to infection, moderate cognitive impairment, mood changes and somatic distress.

The measurement of stress-related immune dysfunction in psychoneuroimmunology

In recent years there has been a dramatic increase in research dedicated to the psycho-behavioural modulation of immune function, i.e. the field of Psychoneuroimmunology (PNI). This has led, necessarily, to the use of several in vitro and in vivo techniques in attempts to delineate the relationship between these two phenomena. However, since the field's inception, considerable uncertainty has existed over the significance of the immune outcomes detected and this has been compounded by the equivocal nature of some of the published data. A great deal of this uncertainty could, however, be overcome if a clearer understanding was achieved on the advantages and limitations conferred by the manifold immune assays described in the literature. This would, in turn, encourage their more appropriate use within PNI. Hence, in this review we describe the rationale behind, and offer an evaluation of, some of the more frequently used in vitro and in vivo immunological and virological techniques. We hope that a clear understanding of the rationale behind such assays and their inherent advantages and limitations will inform the discussion of the significance of stress-related immune impairment.

Health psychology: mapping biobehavioral contributions to health and illness

Our evolving understanding of how psychosocial and behavioral factors affect health and disease processes has been marked by investigation of specific relationships and mechanisms underlying them. Stress and other emotional responses are components of complex interactions of genetic, physiological, behavioral, and environmental factors that affect the body's ability to remain or become healthy or to resist or overcome disease. Regulated by nervous, endocrine, and immune systems, and exerting powerful influence on other bodily systems and key health-relevant behaviors, stress and emotion appear to have important implications for the initiation or progression of cancer, HIV, cardiovascular disease, and other illnesses. Health-enhancing and health-impairing behaviors, including diet, exercise, tobacco use, and protection from the sun, can compromise or benefit health and are directed by a number of influences as well. Finally, health behaviors related to being ill or trying to avoid disease or its severest consequences are important. Seeking care and adhering to medical regimens and recommendations for disease surveillance allow for earlier identification of health threats and more effective treatment. Evidence that biobehavioral factors are linked to health in integrated, complex ways continues to mount, and knowledge of these influences has implications for medical outcomes and health care practice.

Depression and coronary heart disease: observations and questions

The evidence that depressive symptomatology precedes the onset of the acute coronary syndromes and influences the course of disease after their manifestation is accumulating. However, we still are far short of proof that depression has a causal role in the etiology and pathogenesis of coronary heart disease (CHD). Some unsolved questions concern the causes and the nature of the depression preceding a first or recurrent cardiac event, the biological mechanisms relating depression and CHD, the time window of the exposure-disease association, and the power of therapy programs for depression to reduce the risk of a first or recurrent cardiac event.