Extracellular vesicles: Function, resilience, biomarker, bioengineering, and clinical implications.

Extracellular vesicles (EVs) have emerged as key players in intercellular communication, disease pathology, and therapeutic innovation. Initially overlooked as cellular debris, EVs are now recognized as vital mediators of cell-to-cell communication, ferrying a cargo of proteins, nucleic acids, and lipids, providing cellular resilience in response to stresses. This review provides a comprehensive overview of EVs, focusing on their role as biomarkers in disease diagnosis, their functional significance in physiological and pathological processes, and the potential of bioengineering for therapeutic applications. EVs offer a promising avenue for noninvasive disease diagnosis and monitoring, reflecting the physiological state of originating cells. Their diagnostic potential spans a spectrum of diseases, including cancer, cardiovascular disorders, neurodegenerative diseases, and infectious diseases. Moreover, their presence in bodily fluids such as blood, urine, and cerebrospinal fluid enhances their diagnostic utility, presenting advantages over traditional methods. Beyond diagnostics, EVs mediate crucial roles in intercellular communication, facilitating the transfer of bioactive molecules between cells. This communication modulates various physiological processes such as tissue regeneration, immune modulation, and neuronal communication. Dysregulation of EV-mediated communication is implicated in diseases such as cancer, immune disorders, and neurodegenerative diseases, highlighting their therapeutic potential. Bioengineering techniques offer avenues for manipulating EVs for therapeutic applications, from isolation and purification to engineering cargo and targeted delivery systems. These approaches hold promise for developing novel therapeutics tailored to specific diseases, revolutionizing personalized medicine. However, challenges such as standardization, scalability, and regulatory approval need addressing for successful clinical translation. Overall, EVs represent a dynamic frontier in biomedical research with vast potential for diagnostics, therapeutics, and personalized medicine.

Optogenetic control of the integrated stress response reveals proportional encoding and the stress memory landscape.

The integrated stress response (ISR) is a conserved signaling network that detects aberrations and computes cellular responses. Dissecting these computations has been difficult because physical and chemical inducers of stress activate multiple parallel pathways. To overcome this challenge, we engineered a photo-switchable control over the ISR sensor kinase PKR (opto-PKR), enabling virtual, on-target activation. Using light to control opto-PKR dynamics, we traced information flow through the transcriptome and for key downstream ISR effectors. Our analyses revealed a biphasic, proportional transcriptional response with two dynamic modes, transient and gradual, that correspond to adaptive and terminal outcomes. We then constructed an ordinary differential equation (ODE) model of the ISR, which demonstrated the dependence of future stress responses on past stress. Finally, we tested our model using high-throughput light-delivery to map the stress memory landscape. Our results demonstrate that cells encode information in stress levels, durations, and the timing between encounters. A record of this paper's transparent peer review process is included in the supplemental information.

FIR-preconditioning promotes Akt-mTOR-exosome manufacture in cooperation with MITF to boost resilience of rat bone marrow-derived stem cells.

A previous study from our laboratory observed the protective effects of far-infrared irradiation (FIR) on bone marrow-derived stem cells (BMSCs) against oxidative stress. However, it remains unknown precisely how FIR influences BMSC survival. We identify an unexpected route among the expression of MITF, BCL2, mTOR, and exosome in FIR-preconditioned BMSCs. MITF siRNA demonstrated that loss of MITF expression not only inhibited cell proliferation but also reduced the FIR-mediated expression of mTOR, BCL2, and exosome. mTOR signaling pathways have been implicated in cell growth, proliferation, and survival. We also found that rapamycin, a potent and selective inhibitor of mTOR, when combined with MITF siRNA, repressed FIR-mediated CD63 and BCL2 expression. In addition, FIR-preconditioned BMSCs demonstrated more tolerance in multiple stressful environments than untreated BMSCs. The elevated exosomes in conditioned medium derived from FIR-preconditioned BMSCs also repaired H9c2 cells that sustained cellular damage after subjected to an array of environmental stress conditions. Taken together, these results reveal a possible mechanism about how FIR-preconditioned BMSCs and its conditioned media could contribute to cellular resilience during environmental changes via MITF-Akt-mTOR associated with exosome manufacture. FIR preconditioning could thus complement and improve therapeutic applications of BMSCs on outcomes of various disorders.

Endogenous Mechanisms of Neuroprotection: To Boost or Not to Boost.

Postmitotic cells, like neurons, must live through a lifetime. For this reason, organisms/cells have evolved with self-repair mechanisms that allow them to have a long life. The discovery workflow of neuroprotectors during the last years has focused on blocking the pathophysiological mechanisms that lead to neuronal loss in neurodegeneration. Unfortunately, only a few strategies from these studies were able to slow down or prevent neurodegeneration. There is compelling evidence demonstrating that endorsing the self-healing mechanisms that organisms/cells endogenously have, commonly referred to as cellular resilience, can arm neurons and promote their self-healing. Although enhancing these mechanisms has not yet received sufficient attention, these pathways open up new therapeutic avenues to prevent neuronal death and ameliorate neurodegeneration. Here, we highlight the main endogenous mechanisms of protection and describe their role in promoting neuron survival during neurodegeneration.

Is it the time of autophagy fine-tuners for neuroprotection?

Cells and organisms are intrinsically prepared to effectively deal with damage caused by insults and heal themselves by triggering a plethora of stress responses including macroautophagy/autophagy. However, autophagy may become malfunctional during aging, neurodegeneration, and neurotrauma. We aimed to overcome autophagy dysfunction by refining therapeutics using multi-target approaches. Thus, we have demonstrated that modulation of autophagy with the multitarget drug NeuroHeal is neuroprotective in several neurodegeneration models in which previous autophagy modulators have failed. The key element of success is the coordinated activation of opposing forces that modulate autophagy with NeuroHeal, probably leading to the autophagy-dependent degradation of death executors such as PARP1. The precise tuning of autophagy thus allows the neuron to adapt to insults, survive and repair itself. These findings support the advent a new era of neuroprotectants that counteract neuronal damage by targeting in unison different pathways of the self-repair process, including autophagy.

The GH/IGF-1 axis in a critical period early in life determines cellular DNA repair capacity by altering transcriptional regulation of DNA repair-related genes: implications for the developmental origins of cancer.

Experimental, clinical, and epidemiological findings support the concept of developmental origins of health and disease (DOHAD), suggesting that early-life hormonal influences during a sensitive period around adolescence have a powerful impact on cancer morbidity later in life. The endocrine changes that occur during puberty are highly conserved across mammalian species and include dramatic increases in circulating GH and IGF-1 levels. Importantly, patients with developmental IGF-1 deficiency due to GH insensitivity (Laron syndrome) do not develop cancer during aging. Rodents with developmental GH/IGF-1 deficiency also exhibit significantly decreased cancer incidence at old age, marked resistance to chemically induced carcinogenesis, and cellular resistance to genotoxic stressors. Early-life treatment of GH/IGF-1-deficient mice and rats with GH reverses the cancer resistance phenotype; however, the underlying molecular mechanisms remain elusive. The present study was designed to test the hypothesis that developmental GH/IGF-1 status impacts cellular DNA repair mechanisms. To achieve that goal, we assessed repair of γ-irradiation-induced DNA damage (single-cell gel electrophoresis/comet assay) and basal and post-irradiation expression of DNA repair-related genes (qPCR) in primary fibroblasts derived from control rats, Lewis dwarf rats (a model of developmental GH/IGF-1 deficiency), and GH-replete dwarf rats (GH administered beginning at 5 weeks of age, for 30 days). We found that developmental GH/IGF-1 deficiency resulted in persisting increases in cellular DNA repair capacity and upregulation of several DNA repair-related genes (e.g., Gadd45a, Bbc3). Peripubertal GH treatment reversed the radiation resistance phenotype. Fibroblasts of GH/IGF-1-deficient Snell dwarf mice also exhibited improved DNA repair capacity, showing that the persisting influence of peripubertal GH/IGF-1 status is not species-dependent. Collectively, GH/IGF-1 levels during a critical period during early life determine cellular DNA repair capacity in rodents, presumably by transcriptional control of genes involved in DNA repair. Because lifestyle factors (e.g., nutrition and childhood obesity) cause huge variation in peripubertal GH/IGF-1 levels in children, further studies are warranted to determine their persisting influence on cellular cancer resistance pathways.

Stress, Inflammation, and Cellular Vulnerability during Early Stages of Affective Disorders: Biomarker Strategies and Opportunities for Prevention and Intervention.

The mood disorder prodrome is conceptualized as a symptomatic, but not yet clinically diagnosable stage of an affective disorder. Although a growing area, more focused research is needed in the pediatric population to better characterize psychopathological symptoms and biological markers that can reliably identify this very early stage in the evolution of mood disorder pathology. Such information will facilitate early prevention and intervention, which has the potential to affect a person's disease course. This review focuses on the prodromal characteristics, risk factors, and neurobiological mechanisms of mood disorders. In particular, we consider the influence of early-life stress, inflammation, and allostatic load in mediating neural mechanisms of neuroprogression. These inherently modifiable factors have known neuroadaptive and neurodegenerative implications, and consequently may provide useful biomarker targets. Identification of these factors early in the course of the disease will accordingly allow for the introduction of early interventions which augment an individual's capacity for psychological resilience through maintenance of synaptic integrity and cellular resilience. A targeted and complementary approach to boosting both psychological and physiological resilience simultaneously during the prodromal stage of mood disorder pathology has the greatest promise for optimizing the neurodevelopmental potential of those individuals at risk of disabling mood disorders.