Respiratory viral infections are a major cause of morbidity and mortality worldwide. The COVID-19 pandemic has evidenced the need for broad-spectrum antivirals and improved preclinical models that more accurately recapitulate human respiratory disease. These new strategies should also involve the search for drug targets in the infected cell that hamper the development of resistance and of potential efficacy against diverse viruses. Since many viruses reprogram cellular metabolism to support viral replication, we performed a comparative analysis of inhibitors targeting the PI3K/AKT/mTOR pathway, central to virus-induced metabolic adaptations, using MRC5 lung fibroblasts and Huh7 hepatoma cells. HCoV-229E infection in MRC5 cells caused the expected shift in the energy metabolism but the inhibitors had markedly different effects on the metabolic profile and antiviral activity in these two cell lines. Dichloroacetate (DCA), a clinically approved inhibitor of aerobic glycolysis, showed antiviral activity against HCoV-229E in MRC5 cells, but not in Huh7 cells, underscoring that the screening model is more critical than previously assumed. We further tested DCA in polarized human small airway epithelial cells cultured in air-liquid interface, a 3D model that mimics the human respiratory tract. DCA reduced the viral progeny of HCoV-229E, SARS-CoV-2, and respiratory syncytial virus by 2-3 orders of magnitude, even when administered after infection was established. Our work reinforces the need for advanced human preclinical screening models to identify antivirals that target host metabolic pathways frequently hijacked by respiratory viruses, and establishes DCA as a proof-of-concept candidate.

Respiratory viral infections are a significant cause of morbidity and mortality worldwide. COVID-19 pandemic highlighted the lack of chemotherapeutical tools to fight emerging viruses and the need to focus on preclinical models that better recapitulate the human disease. We performed a comparative analysis of inhibitors of the PI3K/AKT/mTOR pathway, involved in the virus-induced metabolic reprogramming, since strategies aimed to cellular targets should serve to combat diverse viruses and hamper the development of resistance. Tests were performed in two human cell lines, MRC5 lung fibroblasts and Huh7 hepatoma cells, and showed that the inhibitors had markedly different effects on energy metabolism and in antiviral activity. Thus, dichloroacetate (DCA) had a potent antiviral activity against HCoV-229E in MRC5 but not in Huh7 cells, implying that the screening model appears to be more critical than previously assumed. DCA was then tested in polarized human alveolar epithelia in air-liquid interface, a 3D model to study respiratory infections. DCA reduced the viral progeny of HCoV-229E, SARS-CoV-2 and the respiratory syncytial virus by 2–3 orders of magnitude, being effective even when applied once infection had been established. Although DCA has previously been shown to be effective against other viruses, suggesting it could be a broad-spectrum antiviral, our experiments reinforce the need to use physiologically appropriate disease models to screen antiviral compounds.

The short and long isoforms of FAIM (FAIM-S and FAIM-L) hold important functions in the central nervous system, and their expression levels are specifically enriched in the retina. We previously described that Faim knockout (KO) mice present structural and molecular alterations in the retina compatible with a neurodegenerative phenotype. Here, we aimed to study Faim KO retinal functions and molecular mechanisms leading to its alterations. Electroretinographic recordings showed that aged Faim KO mice present functional loss of rod photoreceptor and ganglion cells. Additionally, we found a significant delay in dark adaptation from early adult ages. This functional deficit is exacerbated by luminic stress, which also caused histopathological alterations. Interestingly, Faim KO mice present abnormal Arrestin-1 redistribution upon light reception, and we show that Arrestin-1 is ubiquitinated, a process that is abrogated by either FAIM-S or FAIM-L in vitro. Our results suggest that FAIM assists Arrestin-1 light-dependent translocation by a process that likely involves ubiquitination. In the absence of FAIM, this impairment could be the cause of dark adaptation delay and increased light sensitivity. Multiple retinal diseases are linked to deficits in photoresponse termination, and hence, investigating the role of FAIM could shed light onto the underlying mechanisms of their pathophysiology.

Ag2S nanoparticles (NPs) emerge as a unique system that simultaneously features in vivo near-infrared (NIR) imaging, remote heating, and low toxicity thermal sensing. In this work, their capabilities are extended into the fields of optical coherence tomography (OCT), as contrast agents, and NIR probes in both ex vivo and in vivo experiments in eyeballs. The new dual property for ocular imaging is obtained by the preparation of Ag2S NPs ensembles with a biocompatible amphiphilic block copolymer. Rather than a classical ligand exchange, where surface traps may arise due to incomplete replacement of surface sites, the use of this polymer provides a protective extra layer that preserves the photoluminescence properties of the NPs, and the procedure allows for the controlled preparation of submicrometric scattering centers. The resulting NPs ensembles show extraordinary colloidal stability with time and biocompatibility, enhancing the contrast in OCT with simultaneous NIR imaging in the second biological window.

Retinitis pigmentosa (RP) is a genetically heterogeneous disease and the predominant cause of hereditary blindness. Irrespective of the causative mutation, traits common to all forms of RP include photoreceptor dysfunction and death, activation of the retinal glial component, and retinal inflammation. Activation of Toll-like receptors (TLRs) in response to tissue damage is associated with inflammatory processes that contribute to neurodegeneration. We show that retinal expression of the genes Tlr1 to Tlr9 is increased in the rd10 mouse model of RP, with Tlr2 showing the greatest increase (36-fold). Flow cytometry analysis of the retinal myeloid population revealed significant increases in numbers of microglia and infiltrating monocytes and macrophages in rd10 retinas. Furthermore, TLR2 expression, which was restricted to myeloid cells, was increased in rd10 retinal microglia. These observations, together with our previous finding of delayed RP progression following Tlr2 deletion, point to TLR2 as a potential therapeutic target for RP.

Purpose: The photoreceptor degeneration associated to retinitis pigmentosa (RP) is caused by a wide variety of genetic mutations, which greatly complicates the development of a universal effective treatment. As a process independent of the causative mutation, the inflammatory response resulting from neuronal death could represent a potential candidate for a general treatment for RP. In this context, we studied the role of TLR4, one of the main mediators of innate immunity, on the retinal degenerative process in two murine models of RP. Methods: rd10 and P23H/+ mice were used to evaluate the consequences of Tlr4 haploinsufficiency and complete deletion on retinal degeneration. Visual function was evaluated by electroretinographic recordings and optomotor test and retinal cytoarchitecture by immunohistology. The myeloid cell population (main mediators of the innate immune response) reactivity was studied by immunohistology and flow cytometry. Gene expression was assessed by RT-quantitative PCR. Results: We found that Tlr4 expression was significantly increased in the retina of both RP models. To assess the effect of Tlr4 deletion in PR progression first we confirmed that abrogation of Tlr4 expression did not impair visual function in wild-type animals. However, Tlr4 deficiency accelerated RP progression in both rd10 and P23H/+ mice. Deletion of a single Tlr4 allele reduced the retinal electroretinographic response and photoreceptor survival in both RP models. Moreover, complete abrogation of Tlr4 further exacerbates this phenotype. These results were confirmed by assessing visual acuity by optomotor test in P23H/+ mice. Microglia analysis showed higher proportion of phagocytic microglia and lower of homeostatic microglia in the photoreceptor layers upon Tlr4 total deletion. Conclusions: The TLR4 receptor exerts a neuroprotective effect on the retinal neurodegenerative process in RP, thus suggesting a potential therapeutic target for the disease.

Insulin-degrading enzyme (IDE) was named after its role as a proteolytic enzyme of insulin. However, recent findings suggest that IDE is a widely expressed, multitask protein, with both proteolytic and non-proteolytic functions. Here, we characterize the expression of IDE in the mammalian retina in both physiological and pathological conditions. We found that IDE was enriched in cone inner segments. IDE levels were downregulated in the dystrophic retina of several mouse models of retinitis pigmentosa carrying distinct mutations. In rd10 mice, a commonly studied mouse model of retinitis pigmentosa, treatment with an IDE activator (a synthetic peptide analog of preimplantation factor) delayed loss of visual function and preserved photoreceptor cells. Together, these results point to potential novel roles for IDE in retinal physiology and disease, further extending the list of diverse functions attributed to this enzyme.

Synaptic loss, neuronal death, and circuit remodeling are common features of central nervous system neurodegenerative disorders. Retinitis pigmentosa (RP), the leading cause of inherited blindness, is a group of retinal dystrophies characterized by photoreceptor dysfunction and death. The insulin receptor, a key controller of metabolism, also regulates neuronal survival and synaptic formation, maintenance, and activity. Indeed, deficient insulin receptor signaling has been implicated in several brain neurodegenerative pathologies. We present evidence linking impaired insulin receptor signaling with RP. We describe a selective decrease in the levels of the insulin receptor and its downstream effector phospho-S6 in retinal horizontal cell terminals in the rd10 mouse model of RP, as well as aberrant synapses between rod photoreceptors and the postsynaptic terminals of horizontal and bipolar cells. A gene therapy strategy to induce sustained proinsulin, the insulin precursor, production restored retinal insulin receptor signaling, by increasing S6 phosphorylation, without peripheral metabolic consequences. Moreover, proinsulin preserved photoreceptor synaptic connectivity and prolonged visual function in electroretinogram and optomotor tests. These findings point to a disease-modifying role of insulin receptor and support the therapeutic potential of proinsulin in retinitis pigmentosa.

Although considered a rare retinal dystrophy, retinitis pigmentosa (RP) is the primary cause of hereditary blindness. Given its diverse genetic etiology (>3000 mutations in >60 genes), there is an urgent need for novel treatments that target common features of the disease. TLR2 is a key activator of innate immune response. To examine its role in RP progression we characterized the expression profile of Tlr2 and its adaptor molecules and the consequences of Tlr2 deletion in two genetically distinct models of RP: Pde6brd10/rd10 (rd10) and RhoP23H/+ (P23H/+) mice. In both models, expression levels of Tlr2 and its adaptor molecules increased in parallel with those of the proinflammatory cytokine Il1b. In rd10 mice, deletion of a single Tlr2 allele had no effect on visual function, as evaluated by electroretinography. However, in both RP models, complete elimination of Tlr2 attenuated the loss of visual function and mitigated the loss of photoreceptor cell numbers. In Tlr2 null rd10 mice, we observed decreases in the total number of microglial cells, assessed by flow cytometry, and in the number of microglia infiltrating the photoreceptor layers. Together, these results point to TLR2 as a mutation-independent therapeutic target for RP.

The aryl hydrocarbon receptor (AhR) is a ligand‐activated transcription factor, largely known for its role in xenobiotic metabolism and detoxification as well as its crucial role as a regulator of inflammation. Here, we have compared a cohort wild‐type and AhR‐null mice along aging to study the relationship between this receptor and age‐associated inflammation, termed as “inflammaging,” both at a systemic and the CNS level. Our results show that AhR deficiency is associated with a premature aged phenotype, characterized by early inflammaging, as shown by an increase in plasma cytokines levels. The absence of AhR also promotes the appearance of brain aging anatomic features, such as the loss of the white matter integrity. In addition, AhR–/– mice present an earlier spatial memory impairment and an enhanced astrogliosis in the hippocampus when compared with their age‐matched AhR+/+ controls. Importantly, we have found that AhR protein levels decrease with age in this brain structure, strongly suggesting a link between AhR and aging.—Bravo‐Ferrer, I., Cuartero, M. I., Medina, V., Ahedo‐Quero, D., Peña‐Martínez, C., Pérez‐Ruíz, A., Fernández‐Valle, M. E., Hernández‐Sánchez, C., Fernández‐Salguero, P. M., Lizasoain, I., Moro, M. A. Lack of the aryl hydrocarbon receptor accelerates aging in mice. FASEB J. 33, 12644–12654 (2019). www.fasebj.org

As an extension of the central nervous system (CNS), the retina shares with the brain certain developmental, physiological, and pathological characteristics.However, the underlying mechanisms and pathological signs common to neurodegenerative conditions of both the retina and brain have been relatively overlooked.In animal models and in human patients, marked retinal alterations have been demonstrated in Alzheimer´s disease, Parkinson´s disease, and multiple sclerosis, among other pathologies.Furthermore, neurodegeneration of the retina and brain appears to be mediated by similar mechanisms, which include protein aggregation, neuroinflammation, and cell death.Analysis of the retina, which is easily accessible to objective techniques, may therefore constitute an effective tool for the screening and follow-up of CNS neurodegeneration.Moreover, patients with retinal neurodegeneration could potentially benefit from the broad array of pharmacological compounds that have been designed and tested for the treatment of the aforementioned CNS pathologies.Supporting this view, we have shown that GSK-3 inhibitors, which have already been tested in clinical trials to treat several neurodegenerative conditions of the brain, attenuate retinal damage and vision loss in a mouse model of retinitis pigmentosa.Furthermore, systemic proinsulin treatment preserves visual and cognitive function in mouse models of retinitis pigmentosa and precocious aging, respectively.

Enzyme glycogen synthase kinase-3 (GSK-3) is a candidate pharmacological target for the treatment of neurodegenerative diseases of the brain. Given the many molecular, cellular, and functional features shared by the brain and the retina in both physiological and pathological processes, drugs originally designed to treat neurodegenerative diseases of the brain could be useful candidates for the treatment of retinal degenerative pathologies. Moreover, the accessibility of the eye to noninvasive, quantitative diagnostic techniques allows for easier evaluation of the efficacy of candidate therapies in clinical trials. In this chapter, we discuss the potential of GSK-3 inhibitors in the treatment of retinal degeneration.

Tyrosine hydroxylase (TH) catalyzes the first step in catecholamines synthesis. We studied the impact of reduced TH in brown adipose tissue (BAT) activation. In adult heterozygous (Th+/−) mice, dopamine and noradrenaline (NA) content in BAT decreased after cold exposure. This reduced catecholaminergic response did not impair cold adaptation, because these mice induced uncoupling protein 1 (UCP-1) and maintained BAT temperature to a similar extent than controls (Th+/+). Possible compensatory mechanisms implicated were studied. Prdm16 and Fgf21 expression, key genes in BAT activation, were elevated in Th+/− mice at thermoneutrality from day 18.5 of embryonic life. Likewise, plasma FGF21 and liver Fgf21 mRNA were increased. Analysis of endoplasmic reticulum (ER) stress, a process that triggers elevations in FGF21, showed higher phospho-IRE1, phospho-JNK, and CHOP in BAT of Th+/− mice at thermoneutrality. Also, increased lipolysis in BAT of cold-exposure Th+/− mice was demonstrated by increased phosphorylation of hormone-sensitive lipase (HSL), as well as diacylglycerol (DAG) and FFA content. Overall, these results indicate that the mild effects of Th haploinsufficiency on BAT function are likely due to compensatory mechanisms involving elevations in Fgf21 and Prdm16 and through adaptive changes in the lipid profile.

Aging is accompanied by impairment in the nervous, immune, and endocrine systems as well as in neuroimmunoendocrine communication. In this context, there is an age-related alteration of the physiological response to acute stress, which is modulated by catecholamine (CA), final products of the sympathetic-adreno-medullary axis. The involvement of CA in essential functions of the nervous system is consistent with the neuropsychological deficits found in mice with haploinsufficiency (hemizygous; HZ) of tyrosine hydroxylase (TH) enzyme (TH-HZ). However, other possible alterations in regulatory systems have not been studied in these animals. The aim of the present work was to analyze whether adult TH-HZ female mice presented the impairment of behavioral traits and immunological responses that occurs with aging and whether they had affected their mean lifespan. ICR-CD1 female TH-HZ and wild type (WT) mice were used in a longitudinal study. Behavioral tests were performed on adult and old mice in order to evaluate their sensorimotor abilities and exploratory capacity, as well as anxiety-like behaviors. At the ages of 2 +/- 1, 4 +/- 1, 9 +/- 1, 13 +/- 1 and 20 +/- 1 months, peritoneal leukocytes were extracted and several immune functions were assessed (phagocytic capacity, Natural Killer (NK) cytotoxicity, and lymphoproliferative response to lipopolysaccharide (LPS) and concanavalin A (ConA)). In addition, several oxidative stress parameters (catalase, glutathione reductase and glutathione peroxidase activities, and reduced glutathione (GSH) concentrations as antioxidant compounds as well as xanthine oxidase activity, oxidized glutathione (GSSG) concentrations, and GSSG/GSH ratio as oxidants) were analyzed. As inflammatory stress parameters TNF-alpha and IL-10 concentrations, and TNF-alpha/IL-10 ratios as inflammatory/anti-inflammatory markers, were measured. Animals were maintained in standard conditions until their natural death. The results indicate that adult TH-HZ mice presented worse sensorimotor abilities and exploratory capacity than their WT littermates as well as greater anxiety-like behaviors. With regards to the immune system, adult TH-HZ animals exhibited lower values of phagocytic capacity, NK cytotoxicity, and lymphoproliferative response to LPS and ConA than WT mice. Moreover, immune cells of TH-HZ mice showed higher oxidative and inflammatory stress than those of WT animals. Although these differences between TH-HZ and WT, in general, decreased with aging, this premature immunosenescence and impairment of behavior of TH-HZ mice was accompanied by a shorter mean lifespan in comparison to WT counterparts. In conclusion, haploinsufficiency of rh gene in female mice appears to provoke premature aging of the regulatory systems affecting mean lifespan. (C) 2018 Elsevier Inc. All rights reserved.

Proinsulin was first identified as the primary translation product of the insulin gene in Donald Steiner’s laboratory in 1967, and was the first prohormone to be isolated and sequenced. While its role as an insulin precursor has been extensively studied in the field of endocrinology, the bioactivity of the proinsulin molecule itself has received much less attention. Insulin binds to isoforms A and B of the insulin receptor (IR) with high affinity. Proinsulin, in contrast, binds with high affinity only to IR-A, which is present in the nervous system, among other tissues and elicits antiapoptotic and neuroprotective effects in the developing and postnatal nervous system. Proinsulin specifically exerts neuroprotection in the degenerating retina in mouse and rat models of retinitis pigmentosa (RP), delaying photoreceptor and vision loss after local administration in the eye or systemic (intramuscular) administration of an adeno-associated viral (AAV) vector that induces constitutive proinsulin release. AAV-mediated proinsulin expression also decreases the expression of neuroinflammation markers in the hippocampus and sustains cognitive performance in a mouse model of precocious brain senescence. We have therefore proposed that proinsulin should be considered a functionally distinct member of the insulin superfamily. Here, we briefly review the legacy of Steiner’s research, the neural expression of proinsulin, and the tissue expression patterns and functional characteristics of IR-A. We discuss the neuroprotective activity of proinsulin and its potential as a therapeutic tool in neurodegenerative conditions of the central nervous system, particularly in retinal dystrophies.

Background Retinitis pigmentosa (RP) is a group of hereditary retinal neurodegenerative conditions characterized by primary dysfunction and death of photoreceptor cells, resulting in visual loss and, eventually, blindness. To date, no effective therapies have been transferred to clinic. Given the diverse genetic etiology of RP, targeting common cellular and molecular retinal alterations has emerged as a potential therapeutic strategy. Methods Using the Pde6b rd10/rd10 mouse model of RP, we investigated the effects of daily intraperitoneal administration of VP3.15, a small-molecule heterocyclic GSK-3 inhibitor. Gene expression was analyzed by quantitative PCR and protein expression and phosphorylation by Western blot. Photoreceptor preservation was evaluated by histological analysis and visual function was assessed by electroretinography. Results In rd10 retinas, increased expression of pro-inflammatory markers and reactive gliosis coincided with the early stages of retinal degeneration. Compared with wild-type controls, GSK-3β expression (mRNA and protein) remained unchanged during the retinal degeneration period. However, levels of GSK-3β Ser9 and its regulator Akt Ser473 were increased in rd10 versus wild-type retinas. In vivo administration of VP3.15 reduced photoreceptor cell loss and preserved visual function. This neuroprotective effect was accompanied by a decrease in the expression of neuroinflammatory markers. Conclusions These results provide proof of concept of the therapeutic potential of VP3.15 for the treatment of retinal neurodegenerative conditions in general, and RP in particular.

ProNGF signaling through p75 NTR has been associated with neurodegenerative disorders. Retinitis pigmentosa (RP) comprises a group of inherited retinal dystrophies that causes progressive photoreceptor cell degeneration and death, at a rate dependent on the genetic mutation. There are more than 300 mutations causing RP, and this is a challenge to therapy. Our study was designed to explore a common mechanism for p75 NTR in the progression of RP, and assess its potential value as a therapeutic target. The proNGF/p75 NTR system is present in the dystrophic retina of the rd10 RP mouse model. Compared with wild-type (WT) retina, the levels of unprocessed proNGF were increased in the rd10 retina at early degenerative stages, before the peak of photoreceptor cell death. Conversely, processed NGF levels were similar in rd10 and WT retinas. ProNGF remained elevated throughout the period of photoreceptor cell loss, correlating with increased expression of α 2 -macroglobulin, an inhibitor of proNGF processing. The neuroprotective effect of blocking p75 NTR was assessed in organotypic retinal cultures from rd10 and RhoP mouse models. Retinal explants treated with p75 NTR antagonists showed significantly reduced photoreceptor cell death, as determined by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay and by preservation of the thickness of the outer nuclear layer (ONL), where photoreceptor nuclei are located. This effect was accompanied by decreased retinal-reactive gliosis and reduced TNF α secretion. Use of p75 NTR antagonist THX-B (1,3-diisopropyl-1-[2-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-purin-7-yl)-acetyl]-urea) in vivo in the rd10 and RhoP mouse models, by a single intravitreal or subconjunctival injection, afforded neuroprotection to photoreceptor cells, with preservation of the ONL. This study demonstrates a role of the p75 NTR /proNGF axis in the progression of RP, and validates these proteins as therapeutic targets in two different RP models, suggesting utility irrespective of etiology.

La salud depende del buen funcionamiento de los sistemas homeostáticos (el nervioso, endocrino e inmunitario) y de la adecuada comunicación entre ellos. Se ha comprobado que el estado funcional y redox del sistema inmunitario es un excelente marcador de salud, y que una inmunosenescencia prematura supone una menor esperanza de vida. Dado que las catecolaminas modulan la funcionalidad de las células inmunitarias, la alteración en su síntesis podría contribuir a esa inmunosenescencia. Entre las estrategias que se pueden utilizar para controlarla está el ambiente social. Comprobar si una haploinsuficiencia de la tirosina hidroxilasa (TH), enzima limitante de la síntesis de catecolaminas, generaría una inmunosenescencia prematura, y si es posible la modulación de esta por el ambiente social. Se usaron ratones machos ICR-CD1 adultos (9 ± 1 meses) hemizigotos (HZ) para la tirosina hidroxilasa (TH-HZ) y controles (WT), que fueron distribuidos en cuatro subgrupos: WT > 50% (en la jaula, la proporción de WT fue mayor al 50%), WT < 50%, TH-HZ < 50% y TH-HZ > 50%. En leucocitos peritoneales se valoró la fagocitosis, quimiotaxis y linfoproliferación en presencia de lipopolisacárido. También, la actividad de las enzimas antioxidantes glutatión reductasa y glutatión peroxidasa, y el cociente glutatión oxidado/glutatión reducido. Los TH-HZ > 50% presentaron, en leucocitos, una funcionalidad y estado redox deteriorados respecto a WT > 50 y similar a ratones viejos. Sin embargo, los TH-HZ < 50% mostraron valores similares a los WT < 50%. Una haploinsuficiencia de la enzima TH provoca una inmunosenescencia prematura, la cual puede ser compensada por la convivencia con un número apropiado de animales WT. Healthy state depends on the appropriate function of the homeostatic systems (nervous, endocrine and immune systems) and the correct communication between them. The functional and redox state of the immune system is an excellent marker of health, and animals with premature immunosenescence show a shorter lifespan. Since catecholamines modulate the function of immune cells, the alteration in their synthesis could provoke immunosenescence. The social environment could be a strategy for modulating this immunosenescence. To determine if an haploinsufficiency of tyrosine hydroxylase (TH), the limiting enzyme of synthesis of catecholamines, may produce a premature immunosenescence and if this immunosenescence could be modulated by the social environment. Adult (9 ± 1 months) male ICR-CD1 mice with deletion of a single allele (hemi-zygotic: HZ) of the tyrosine hydroxylase enzyme (TH-HZ) and wild-type (WT) mice were used. Animals were housed in four subgroups: WT > 50% (in the cage, the proportion of WT mice was higher than 50% in relation to TH-HZ), WT < 50%, TH-HZ < 50% and TH-HZ > 50%. Peritoneal leukocytes were collected and phagocytosis, chemotaxis and proliferation of lymphocytes in the presence of lipopolysaccharide were analyzed. Glutathione reductase and glutathione peroxidase activities as well as oxidized/reduced glutathione ratio were studied. TH-HZ > 50% mice showed a deteriorated function and redox state in leukocytes respect to WT > 50% and similar to old mice. However, TH-HZ < 50% animals had similar values to those found in WT < 50% mice. The haploinsufficiency of TH generates premature immunosenescence, which appears to be compensated by living together with an appropriate number of WT animals.