Aging with HIV poses unique and complex challenges, including avoidance of neurocognitive disorder. Our objective here is to identify the prevalence and predictors of successful cognitive aging (SCA) in a sample of older adults with HIV. One hundred three HIV-infected individuals aged 50 and older were recruited from the Modena HIV Metabolic Clinic in Italy. Participants were treated with combination antiretroviral therapy for at least 1 year and had suppressed plasma HIV viral load. SCA was defined as the absence of neurocognitive impairment (as defined by deficits in tasks of episodic learning, information processing speed, executive function, and motor skills) depression, and functional impairment (instrumental activities of daily living). In cross-sectional analyses, odds of SCA were assessed in relation to HIV-related clinical data, HIV-Associated Non-AIDS (HANA) conditions, multimorbidity (≥2HANA conditions), and frailty. A frailty index was calculated as the number of deficits present out of 37 health variables. SCA was identified in 38.8% of participants. Despite no differences in average chronologic age between groups, SCA participants had significantly fewer HANA conditions, a lower frailty index, and were less likely to have hypertension. In addition, hypertension (odds ratio [OR] = 0.40, p = .04), multimorbidity (OR = 0.35, p = .05), and frailty (OR = 0.64, p = .04) were significantly associated with odds of SCA. Frailty is associated with the likelihood of SCA in people living with HIV. This defines an opportunity to apply knowledge from geriatric population research to people aging with HIV to better appreciate the complexity of their health status.

Background

Despite a number of different transgenes that can mediate DNA deletion in the developing lens, each has unique features that can make a given transgenic line more or less appropriate for particular studies. The purpose of this work encompasses both a review of transgenes that lead to the expression of Cre recombinase in the lens and a comparative analysis of currently available transgenic lines with a particular emphasis on the Le-Cre and P0-3.9GFPCre lines that can mediate DNA deletion in the lens placode. Although both of these transgenes are driven by elements of the Pax6 P0 promoter, the Le-Cre transgene consistently leads to ocular abnormalities in homozygous state and can lead to ocular defects on some genetic backgrounds when hemizygous.

Result

Although both P0-3.9GFPCre and Le-Cre hemizygous transgenic mice undergo normal eye development on an FVB/N genetic background, Le-Cre homozygotes uniquely exhibit microphthalmia. Examination of the expression patterns of these two transgenes revealed similar expression in the developing eye and pancreas. However, lineage tracing revealed widespread non-ocular CRE reporter gene expression in the P0-3.9GFPCre transgenic mice that results from stochastic CRE expression in the P0-3.9GFPCre embryos prior to lens placode formation. Postnatal hemizygous Le-Cre transgenic lenses express higher levels of CRE transcript and protein than the hemizygous lenses of P0-3.9GFPCre mice. Transcriptome analysis revealed that Le-Cre hemizygous lenses deregulated the expression of 15 murine genes, several of which are associated with apoptosis. In contrast, P0-3.9GFPCre hemizygous lenses only deregulated two murine genes. No known PAX6-responsive genes or genes directly associated with lens differentiation were deregulated in the hemizygous Le-Cre lenses.

Conclusions

Although P0-3.9GFPCre transgenic mice appear free from ocular abnormalities, extensive non-ocular CRE expression represents a potential problem for conditional gene deletion studies using this transgene. The higher level of CRE expression in Le-Cre lenses versus P0-3.9GFPCre lenses may explain abnormal lens development in homozygous Le-Cre mice. Given the lack of deregulation of PAX6-responsive transcripts, we suggest that abnormal eye development in Le-Cre transgenic mice stems from CRE toxicity. Our studies reinforce the requirement for appropriate CRE-only expressing controls when using CRE as a driver of conditional gene targeting strategies.

The monocytic/macrophage system is essential for skeletal muscle homeostasis, but its dysregulation contributes to the pathogenesis of muscle degenerative disorders. Despite our increasing knowledge of the role of macrophages in degenerative disease, it still remains unclear how macrophages contribute to muscle fibrosis. Here, we used single-cell transcriptomics to determine the molecular attributes of dystrophic and healthy muscle macrophages. We identified six novel clusters. Unexpectedly, none corresponded to traditional definitions of M1 or M2 macrophage activation. Rather, the predominant macrophage signature in dystrophic muscle was characterized by high expression of fibrotic factors, galectin-3 and spp1. Spatial transcriptomics and computational inferences of intercellular communication indicated that spp1 regulates stromal progenitor and macrophage interactions during muscular dystrophy. Galectin-3 + macrophages were chronically activated in dystrophic muscle and adoptive transfer assays showed that the galectin-3 + phenotype was the dominant molecular program induced within the dystrophic milieu. Histological examination of human muscle biopsies revealed that galectin-3 + macrophages were also elevated in multiple myopathies. These studies advance our understanding of macrophages in muscular dystrophy by defining the transcriptional programs induced in muscle macrophages, and reveal spp1 as a major regulator of macrophage and stromal progenitor interactions.

Macrophages are essential for skeletal muscle homeostasis, but how their dysregulation contributes to the development of fibrosis in muscle disease remains unclear. Here, we used single-cell transcriptomics to determine the molecular attributes of dystrophic and healthy muscle macrophages. We identified six clusters and unexpectedly found that none corresponded to traditional definitions of M1 or M2 macrophages. Rather, the predominant macrophage signature in dystrophic muscle was characterized by high expression of fibrotic factors, galectin-3 (gal-3) and osteopontin (Spp1). Spatial transcriptomics, computational inferences of intercellular communication, and in vitro assays indicated that macrophage-derived Spp1 regulates stromal progenitor differentiation. Gal-3⁺ macrophages were chronically activated in dystrophic muscle, and adoptive transfer assays showed that the gal-3⁺ phenotype was the dominant molecular program induced within the dystrophic milieu. Gal-3⁺ macrophages were also elevated in multiple human myopathies. These studies advance our understanding of macrophages in muscular dystrophy by defining their transcriptional programs and reveal Spp1 as a major regulator of macrophage and stromal progenitor interactions.