Effect of Preemptive Intervention on Developmental Outcomes Among Infants Showing Early Signs of Autism: A Randomized Clinical Trial of Outcomes to Diagnosis.

Importance: Intervention for individuals with autism spectrum disorder (ASD) typically commences after diagnosis. No trial of an intervention administered to infants before diagnosis has shown an effect on diagnostic outcomes to date. Objective: To determine the efficacy of a preemptive intervention for ASD beginning during the prodromal period. Design, Setting, and Participants: This 2-site, single rater-blinded randomized clinical trial of a preemptive intervention vs usual care was conducted at 2 Australian research centers (Perth, Melbourne). Community sampling was used to recruit 104 infants aged 9 to 14 months showing early behaviors associated with later ASD, as measured by the Social Attention and Communication Surveillance-Revised. Recruitment occurred from June 9, 2016, to March 30, 2018. Final follow-up data were collected on April 15, 2020. Interventions: Infants were randomized on a 1:1 ratio to receive either a preemptive intervention plus usual care or usual care only over a 5-month period. The preemptive intervention group received a 10-session social communication intervention, iBASIS-Video Interaction to Promote Positive Parenting (iBASIS-VIPP). Usual care comprised services delivered by community clinicians. Main Outcomes and Measures: Infants were assessed at baseline (approximate age, 12 months), treatment end point (approximate age, 18 months), age 2 years, and age 3 years. Primary outcome was the combined blinded measure of ASD behavior severity (the Autism Observation Scale for Infants and the Autism Diagnostic Observation Schedule, second edition) across the 4 assessment points. Secondary outcomes were an independent blinded clinical ASD diagnosis at age 3 years and measures of child development. Analyses were preregistered and comprised 1-tailed tests with an α level of .05. Results: Of 171 infants assessed for eligibility, 104 were randomized; 50 infants (mean [SD] chronological age, 12.40 [1.93] months; 38 boys [76.0%]) received the iBASIS-VIPP preemptive intervention plus usual care (1 infant was excluded after randomization), and 53 infants (mean [SD] age, 12.38 [2.02] months; 32 boys [60.4%]) received usual care only. A total of 89 participants (45 in the iBASIS-VIPP group and 44 in the usual care group) were reassessed at age 3 years. The iBASIS-VIPP intervention led to a reduction in ASD symptom severity (area between curves, -5.53; 95% CI, -∞ to -0.28; P = .04). Reduced odds of ASD classification at age 3 years was found in the iBASIS-VIPP group (3 of 45 participants [6.7%]) vs the usual care group (9 of 44 participants [20.5%]; odds ratio, 0.18; 95% CI, 0-0.68; P = .02). Number needed to treat to reduce ASD classification was 7.2 participants. Improvements in caregiver responsiveness and language outcomes were also observed in the iBASIS-VIPP group. Conclusions and Relevance: Receipt of a preemptive intervention for ASD from age 9 months among a sample of infants showing early signs of ASD led to reduced ASD symptom severity across early childhood and reduced the odds of an ASD diagnosis at age 3 years. Trial Registration: http://anzctr.org.au identifier: ACTRN12616000819426.

History of discovery: platelet-derived growth factor.

A growth-promoting activity released from activated platelets, the platelet-derived growth factor, was discovered and characterized while the cellular and molecular mechanisms underlying the formation of the lesions of atherosclerosis were being investigated. This review provides a personal account of the different challenges we faced 3 decades ago in this undertaking and describes how our path was influenced by our focus on a disease process and by the evolving general understanding of the molecular effectors of cell proliferation.

The neurosecretory vesicle protein phogrin functions as a phosphatidylinositol phosphatase to regulate insulin secretion.

Phogrin is a transmembrane protein expressed in cells with stimulus-coupled peptide hormone secretion, including pancreatic beta cells, in which it is localized to the membrane of insulin-containing dense-core vesicles. By sequence, phogrin is a member of the family of receptor-like protein-tyrosine phosphatases, but it contains substitutions in conserved catalytic sequences, and no significant enzymatic activity for phogrin has ever been reported. We report here that phogrin is able to dephosphorylate specific inositol phospholipids, including phosphatidylinositol (PI) 3-phosphate and PI 4,5-diphosphate but not PI 3,4,5-trisphosphate. The phosphatidylinositol phosphatase (PIPase) activity of phogrin was measurable but low when evaluated by the ability of a catalytic domain fusion protein to hydrolyze soluble short-chain phosphatidylinositol phospholipids. Unlike most PIPases, which are cytoplasmic proteins that associate with membranes, mature phogrin is a transmembrane protein. When the transmembrane form of phogrin was overexpressed in mammalian cells, it reduced plasma membrane phosphatidylinositol 4,5-disphosphate levels in a dose-dependent manner. When purified and assayed in vitro, the transmembrane form had a specific activity of 142 mol/min/mol, 75-fold more active than the catalytic domain fusion protein and comparable with the specific activities of the other PIPases. The PIPase activity of phogrin depended on the catalytic site cysteine and correlated with effects on glucose-stimulated insulin secretion. We propose that phogrin functions as a phosphatidylinositol phosphatase that contributes to maintaining subcellular differences in levels of PIP that are important for regulating stimulus-coupled exocytosis of insulin.

Diabetes and aging alter bone marrow contributions to tissue maintenance.

Bone marrow-derived cells contribute to repair of injured tissue and to the maintenance of tissue homeostasis, but the extent to which perturbations of systemic homeostasis modulate this contribution is unknown. Accordingly, hematopoietic chimeras were used to determine contributions of bone marrow-derived cells to hepatocytes, skeletal muscle myocytes, and cardiomyocytes in healthy young, healthy old, and young obese diabetic mice. Mice with multiple genomic copies of a non-expressed ß-globin/pBR322 sequence served as bone marrow donors. Because detection of the integrated sequence does not involve gene expression and many copies of the sequence are present, the sensitivity of detection is high and is not influenced by the state of cell differentiation. Our data indicate that bone marrow contributes a significant fraction of hepatocytes in old and diabetic mice, but half as many in young mice. They also show that bone marrow is a significant source of new cardiomyocytes at all ages and that this contribution is unaffected by diabetes. Additionally we found that bone marrow makes a substantial contribution to skeletal myocyte replacement that decreases with age. In summary, bone marrow-derived cells contribute significantly to normal non-hematopoietic cell replacement, a contribution that is altered by overall homeostatic state in a tissue specific manner. These data are significant if we are to understand if, and if so how, bone marrow-derived cell dysfunction contributes to tissue damage and senescence.

Vasodilator-stimulated phosphoprotein regulates proliferation and growth inhibition by nitric oxide in vascular smooth muscle cells.

OBJECTIVE: Vasodilator-stimulated phosphoprotein (VASP) was identified as a substrate for cGMP-dependent protein kinase (PKG) and cAMP-dependent protein kinase (PKA). It is preferentially phosphorylated at serine239 by PKG, whereas serine157 is a preferred phosphorylation site for PKA. In addition, serine157 is phosphorylated by PKC in response to serum. We have investigated the effects of VASP and VASP phosphorylation at serine157 and serine239 on smooth muscle cell (SMC) proliferation and nitric oxide (NO)-mediated growth inhibition. METHODS AND RESULTS: Aortic SMCs derived from VASP-deficient mice were transduced with retroviral vectors encoding either wild-type VASP or VASP mutants (S157A-VASP and S239A-VASP), in which serine157 and serine239, respectively, were replaced by a nonphosphorylatable amino acid, alanine. Expression of wt-VASP and S239A-VASP significantly increased proliferation, whereas expression of S157A-VASP was inhibitory. Expression of S239A-VASP rendered SMCs less sensitive to growth inhibition by the NO donor, S-nitroso-n-acetylpenicillamine, when compared with cells expressing wt-VASP. Similar effects were observed in cultured rat SMCs in which wt-VASP, S157A-VASP, and S239A-VASP were expressed. CONCLUSIONS: Our data suggest that VASP phosphorylation at serine157 is required for the growth-stimulatory effect of VASP in SMCs, whereas VASP phosphorylation at serine239 is involved in the growth inhibitory effects of NO on SMCs.

Chimera analysis supports a predominant role of PDGFRbeta in promoting smooth-muscle cell chemotaxis after arterial injury.

The carotid artery shows a common response to many forms of injury, including a rapid activation of smooth muscle cell (SMC) proliferation in the media and migration of SMCs into the intima to form a neointima. Platelet-derived growth factor (PDGF) is believed to play a role in this response to injury, but it has proven difficult to distinguish whether it is stimulating cell migration or cell proliferation, and whether the action is direct or indirect. To determine this, we created chimeric mice composed of both wild-type (WT) and marked PDGF receptor beta (PDGFRbeta)-deficient cells, and determined the consequences of PDGFRbeta expression for SMC participation in response to ligation of the left common carotid artery. The proportion of PDGFRbeta-/- SMCs increased 4.5-fold in the media and decreased 1.8-fold during formation of the neointima, consistent with migration of WT SMCs out of the media and into the intima, leaving the PDGFRbeta-/- cells behind. The fibrotic reaction in the adventitia, which does not involve cell migration, did not result in any change in relative abundance of WT and PDGFRbeta-deficient fibroblasts. We conclude that the most significant direct role of PDGFRbeta is to mediate responses that involve cell migration rather than proliferation.

Fas and Fas-associated death domain protein regulate monocyte chemoattractant protein-1 expression by human smooth muscle cells through caspase- and calpain-dependent release of interleukin-1alpha.

We previously reported that treatment of human vascular smooth muscle cells (SMCs) with proapoptotic stimuli, including Fas ligand plus cycloheximide (FasL/Chx), or overexpression of Fas-associated death domain protein (FADD) result in increased expression of monocyte chemoattractant protein-1 (MCP-1) and other proinflammatory genes. In this study, we demonstrate that Fas/FADD-induced MCP-1 upregulation is driven by an autocrine/paracrine signaling loop in which interleukin (IL)-1alpha synthesis and release are activated through caspase- and calpain-dependent processes. Untreated SMCs contain very little IL-1alpha protein or transcript. Both were increased greatly in response to Fas/FADD activation, primarily through an autocrine/paracrine pathway in which secreted IL-1alpha stimulated additional IL-1alpha synthesis and release. Caspase 8 (Csp8) activity increased in response to FasL/Chx treatment, and Csp8 inhibitors markedly reduced IL-1alpha release and MCP-1 upregulation. In contrast, Csp8 activity was not significantly increased in response to FADD overexpression and caspase inhibitors did not effect FADD-induced MCP-1 upregulation. Both FasL/Chx treatment and FADD overexpression increased the activity of calpains. Calpain inhibitors reduced IL-1alpha release and MCP-1 upregulation in both FADD-overexpressing SMCs and FasL/Chx-treated SMCs without blocking Csp8 activity. This indicates that calpains are not required for activation of caspases and that caspase activation is not sufficient for IL-1alpha release and MCP-1 upregulation. These data suggest that calpains play a dominant role in Fas/FADD-induced IL-1alpha release and MCP-1 upregulation and that caspase activation may function to amplify the effects of calpain activation.